Produced by Suzanne Lybarger, Brian Janes and the Online
Distributed Proofreading Team at http://www.pgdp.net










INDUSTRIAL POISONING

FROM FUMES, GASES AND POISONS OF MANUFACTURING PROCESSES

    BY THE SAME AUTHOR

    LEAD POISONING AND LEAD ABSORPTION:

    THE SYMPTOMS, PATHOLOGY AND PREVENTION, WITH SPECIAL REFERENCE
    TO THEIR INDUSTRIAL ORIGIN AND AN ACCOUNT OF THE PRINCIPAL
    PROCESSES INVOLVING RISK.

    By THOMAS M. LEGGE M.D. (Oxon.), D.P.H. (Cantab.), H.M. Medical
    Inspector of Factories; Lecturer on Factory Hygiene, University
    of Manchester; and KENNETH W. GOADBY, D.P.H. (Cantab.),
    Pathologist and Lecturer on Bacteriology, National Dental
    Hospital. Illustrated. viii+308 pp. 12s. 6_d._ net.

    LONDON: EDWARD ARNOLD.




                          INDUSTRIAL POISONING

                      FROM FUMES, GASES AND POISONS
                       OF MANUFACTURING PROCESSES

                                   BY
                            DR. J. RAMBOUSEK
                      PROFESSOR OF FACTORY HYGIENE,
                 AND CHIEF STATE HEALTH OFFICER, PRAGUE

                        TRANSLATED AND EDITED BY
                      THOMAS M. LEGGE, M.D., D.P.H.
                   H.M. MEDICAL INSPECTOR OF FACTORIES
          JOINT AUTHOR OF ‘LEAD POISONING AND LEAD ABSORPTION’

                           WITH ILLUSTRATIONS

                                 LONDON
                              EDWARD ARNOLD
                                  1913




TRANSLATOR’S PREFACE


I undertook the translation of Dr. Rambousek’s book because it seemed to
me to treat the subject of industrial poisons in as novel, comprehensive,
and systematic a manner as was possible within the compass of a single
volume. Having learnt much myself from Continental writings on industrial
diseases and factory hygiene, I was anxious to let others also see how
wide a field they had covered and how thorough were the regulations for
dangerous trades abroad, especially in Germany. A praiseworthy feature of
Dr. Rambousek’s book was the wealth of references to the work of foreign
writers which is made on almost every page. To have left these names
and references, however, in the text as he has done would have made the
translation tedious reading, and therefore for the sake of those who
desire to pursue inquiry further I have adopted the course of collecting
the great majority and placing them all together in an appendix at the
end of the volume.

Dr. Rambousek as a medical man, a chemist, and a government official
having control of industrial matters, is equipped with the very special
knowledge required to describe the manufacturing processes giving rise
to injurious effects, the pathology of the lesions set up, and the
preventive measures necessary to combat them. In his references to work
done in this country he has relied largely on abstracts which have
appeared in medical and technical journals published on the Continent. I
have only thought it necessary to amplify his statements when important
work carried out here on industrial poisoning,—such as that on nickel
carbonyl and on ferro-silicon—had been insufficiently noted. Such
additions are introduced in square brackets or in footnotes.

In his preface Dr. Rambousek says ‘the book is intended for all who
are, or are obliged to be, or ought to be, interested in industrial
poisoning.’ No words could better describe the scope of the book.

The work of translation would never have been begun but for the
assistance given me in Parts II and III by my sister, Miss H. Edith
Legge. To her, and to Mr. H. E. Brothers, F.I.C., who has been to the
trouble of reading the proofs and correcting many mistakes which my
technical knowledge was insufficient to enable me to detect, my best
thanks are due.

I am indebted to Messrs. Davidson & Co., Belfast, for permission to use
figs. 46 and 48; to Messrs. Locke, Lancaster & Co., Millwall, for fig.
27; to Mr. R. Jacobson, for figs. 30, 33, 37, 38, and 43; to Messrs.
Siebe, Gorman & Co., for figs. 32, 39, and 40; to Messrs. Blackman & Co.
for fig. 47; to Messrs. Matthews & Yates for fig. 54; to H.M. Controller
of the Stationery Office for permission to reproduce figs. 52, 53, and
54, and the diagrams on p. 284; and lastly to my publisher, for figs. 41,
42, 43, and 49, which are taken from the book by Dr. K. W. Goadby and
myself on ‘Lead Poisoning and Lead Absorption.’

                                                                 T. M. L.

HAMPSTEAD, _May 1913_.




CONTENTS


                                                                      PAGE

    INTRODUCTION                                                      xiii

    Part I.—Description of the industries and processes attended
    with risk of poisoning: incidence of such poisoning

    CHEMICAL INDUSTRY                                                    1
      Sulphuric acid industry (sulphur dioxide): use of sulphuric acid   4
        Its effects on health                                            9
      Hydrochloric acid, saltcake and soda industry                     14
        Their effects on health                                         20
      Use of sulphate and sulphide of soda                              22
        Ultramarine                                                     22
        Sulphonal                                                       22
        Diethyl sulphate                                                23
      Chlorine, chloride of lime and chlorates                          23
        Their effect on health                                          26
      Other chlorine compounds and their use as well as bromine,
          iodine and fluorine                                           29
        Chlorides of phosphorus                                         30
        Chlorides of sulphur                                            31
        Zinc chloride                                                   32
        Rock salt                                                       32
      Organic chlorine compounds                                        32
        Carbon oxychloride (phosgene)                                   32
        Carbon chlorine compounds (aliphatic)                           33
        Methyl chloride                                                 33
        Methylene chloride                                              34
        Carbon tetrachloride                                            34
        Ethyl chloride                                                  34
        Monochloracetic acid                                            34
        Chloral                                                         34
        Chloroform                                                      34
        Chloride of nitrogen                                            35
        Cyanogen chloride                                               35
        Chlorobenzene                                                   35
          Benzo trichloride, benzyl chloride                            35
          Nitro- and dinitro-chlorobenzene                              35
        Iodine and iodine compounds                                     36
        Bromine and bromine compounds                                   36
          Methyl iodide and methyl bromide                              36
        Fluorine compounds                                              37
          Hydrofluoric and silicofluoric acids                          38
      Manufacture and uses of nitric acid                               39
        Its effect on health                                            40
      Nitric and nitrous salts and compounds                            44
        Barium nitrate                                                  44
        Ammonium nitrate                                                44
        Lead nitrate                                                    44
        Mercurous and mercuric nitrate                                  44
        Silver nitrate                                                  45
        Sodium nitrite                                                  45
        Amyl nitrite                                                    45
      Manufacture of explosives and their effects                       45
        Fulminate of mercury                                            46
        Nitro-glycerin                                                  46
        Dynamite                                                        47
        Gun cotton                                                      48
        Collodion cotton, smokeless powder                              48
      Manufacture of phosphorus and lucifer matches and their effects   49
        Other uses of phosphorus and compounds of phosphorus            52
          Phosphor-bronze                                               52
          Sulphide of phosphorus                                        52
          Phosphoretted hydrogen                                        52
        Superphosphate and artificial manure                            53
        Basic slag                                                      54
      Chromium compounds and their uses                                 55
        Sodium and potassium bichromate                                 55
        Lead chromate and chrome colours                                55
        Their effect on health                                          56
      Manganese compounds and their effects                             58
      Mineral oil industry and the use of petroleum and benzine         59
        Chemical cleaning                                               61
        Their effect on health                                          61
      Recovery and use of sulphur                                       64
        Its effect on health                                            65
      Sulphuretted hydrogen and its effect                              65
      Preparation and use of carbon bisulphide in vulcanising, &c.      68
        Its effect on health                                            69
      Preparation of illuminating gas                                   71
        Its effect on health                                            74
      Coke ovens and risk from them                                     77
      Other kinds of power and illuminating gas                         80
        Producer gas                                                    80
        Blast furnace gas                                               82
        Water gas                                                       82
        Dowson and Mond gas                                             82
        Suction gas                                                     83
        Acetylene (calcium carbide)                                     85
        Their effect on health                                          87
      Ammonia and ammonium compounds                                    90
        Use of ammonia and its effects                                  92
      Cyanogen compounds                                                93
        Use of cyanide, and their effects                               95
      Coal tar and tar products                                         96
        Their effects on health                                        101
        Artificial organic dye stuffs (coal tar colours)               107
          Their effects on health                                      112
    RECOVERY AND USE OF METALS                                         120
      Lead poisoning in general                                        120
      Lead, silver and zinc smelting                                   122
        Spelter works                                                  125
      Lead poisoning in lead smelting and spelter works                126
      White lead and other use of lead colours                         131
        Lead poisoning in the manufacture and use of white lead
          and lead paints                                              132
      Manufacture of electric accumulators                             134
      The ceramic industry                                             135
        Coarse ware pottery                                            136
        Manufacture of stove tiles                                     137
        Stoneware and porcelain                                        138
      Lead poisoning in letterpress printing                           138
      Lead poisoning in filecutting, polishing precious stones,
          musical instrument making, &c.                               140
      Mercury (poisoning in its recovery and use)                      141
        Mercurial poisoning in water-gilding, coating mirrors, in
          felt hat making, &c.                                         142
      Arsenic (poisoning in its recovery and in use of arsenic and
          arsenic compounds)                                           143
        Recovery of arsenic and white arsenic                          143
        Poisoning by arseniuretted hydrogen gas                        145
      Antimony                                                         146
      Extraction of iron                                               146
        Ferro-silicon                                                  149
        Zinc                                                           151
        Copper, brass (brassfounders’ ague)                            151
        Metal pickling                                                 152
    OTHER INDUSTRIES                                                   153
        Treatment of stone and earths; lime burning, glass             153
        Treatment of animal products                                   154
        Preparation of vegetable foodstuffs                            154
        Poisonous woods                                                154
        Textile industry                                               156

    Part II.—Pathology and treatment of industrial poisoning

    INDUSTRIAL POISONS IN GENERAL                                      157
      Channels of absorption, classification, susceptibility,
        immunity                                                       158
      Fate of poisons in the body—absorption, cumulative action,
        excretion                                                      162
      General remarks on treatment                                     163
    INDUSTRIAL POISONS IN PARTICULAR                                   169
      Group: mineral acids, halogens, inorganic halogen compounds,
          alkalis                                                      169
        Hydrochloric acid                                              170
        Hydrofluoric and silico-fluoric acids                          171
        Sulphur dioxide and sulphuric acid                             171
        Nitrous fumes, nitric acid                                     172
        Chlorine, bromine, iodine                                      173
        Chlorides of phosphorus, sulphur and zinc                      174
        Ammonia                                                        175
        Alkalis                                                        176
      Group: Metals and metal-compounds                                176
        Lead and its compounds                                         177
        Zinc and its alloys                                            182
        Mercury and its compounds                                      183
        Manganese and its compounds                                    184
        Chromium and its compounds                                     185
        Nickel salts (nickel carbonyl)                                 186
        Copper                                                         188
        Silver and its compounds                                       188
      Group: Arsenic, Phosphorus                                       189
        Arsenic and its oxides                                         189
        Phosphorus                                                     190
        Phosphoretted hydrogen                                         191
      Group: Sulphuretted hydrogen, carbon bisulphide, and cyanogen
          (nerve poisons)                                              192
        Sulphuretted hydrogen                                          192
        Carbon bisulphide                                              193
        Cyanogen compounds                                             195
      Group: Arseniuretted hydrogen and carbonic oxide (blood
          poisons)                                                     197
      Group: Hydrocarbons of the aliphatic and aromatic series and
          their halogen and hydroxyl substitution products             202
        Sub-group: Hydrocarbons of mineral oils and their distillation
            products (benzine, paraffin, &c.)                          202
        Sub-group: Hydrocarbons of the aromatic series                 204
          Benzene and its homologues                                   204
          Naphthalene                                                  208
        Sub-group: Halogen substitution products of the aliphatic
            series (narcotic poisons)                                  208
        Sub-group: Halogen substitution products of the benzene
            series                                                     209
        Sub-group: Hydroxyl substitution products of the fatty
            series                                                     210
      Group: Nitro- and amido-derivatives of the aliphatic and
            aromatic series                                            211
        Sub-group: Nitro-derivatives of the aliphatic series           212
        Sub-group: Nitro- and amido-derivatives of the aromatic
            series                                                     212
      Turpentine, pyridene, alkaloids, nicotine, poisonous woods       215

    Part III.—Preventive measures against industrial poisoning

    GENERAL PREVENTIVE MEASURES                                        217
      International action, notification of poisoning, schedules
            of poisons                                                 218
      Special preventive measures for workers—selection, periodical
            medical examination, co-operation of workers, &c.          226
        Rescue appliances                                              230
        Washing accommodation and baths                                237
      Removal of dust and fumes by exhaust ventilation                 242
    PREVENTIVE MEASURES IN PARTICULAR INDUSTRIES                       256
      Sulphuric acid industry                                          256
      Hydrochloric acid and soda industries                            257
      Chlorine, bleaching powder, chlorine compounds                   259
      Manufacture of nitric acid and explosives                        260
      Artificial manures, basic slag                                   261
      Chromium and its compounds                                       265
      Petroleum, benzine                                               267
      Phosphorus, lucifer matches                                      268
      Bisulphide of carbon                                             271
      Illuminating gas, tar production                                 275
      Gas power plant                                                  276
        Acetylene gas installations                                    278
      Ammonia                                                          279
      Cyanogen, cyanogen compounds                                     280
      Coal tar, tar products                                           280
      Organic dye-stuffs, coal tar colours                             285
      Recovery and use of metals                                       288
        Iron                                                           289
        Lead                                                           292
          Lead smelting                                                299
          Electric accumulators                                        305
          White lead and lead colours                                  310
          Letterpress printing                                         316
          Ceramic industry                                             319
          File cutting                                                 321
          Other uses of lead                                           322
        Zinc smelting                                                  323
          Brass casting, metal pickling                                325
        Recovery and use of mercury                                    326
        Arsenic and its compounds                                      328
        Gold and silver                                                329
    PREVENTIVE MEASURES IN OTHER TRADES                                329
      Manufacture and use of varnishes                                 330
      Production of vegetable foods                                    332
      Wood working                                                     335
      Paper manufacture                                                336
      Textile industries                                               336

    APPENDIX                                                           339

    INDEX                                                              355




INTRODUCTION


The attempt to systematise from the scientific standpoint the mass of
material that has been collected about poisons is a very heavy task, even
for the toxicologist who desires to treat his subject comprehensively.
How much greater is the difficulty of writing a systematic book on
industrial poisoning keeping practical application in the forefront!

Technical considerations which are decisive in the causation and
prevention of industrial poisoning are here of especial moment, and must
naturally influence classification of the subject-matter when the object
is to assist those concerned in factory hygiene.

Bearing this in mind, I have divided the subject into three parts. The
arrangement of the first, which gives as complete a statement as possible
of the occurrence of industrial poisoning, into industries and processes
was determined on technical grounds. The second, which amplifies the
first, attempts to summarise the pathology or symptoms of the various
forms of poisoning. The references to the literature of the particular
subjects—as exhaustive as I could make them—will lighten further study.
To these two parts, following on knowledge of causation and symptoms, the
third, in which preventive measures are outlined, is linked.

The apparent drawback in use of the book is that one form of poisoning
has often to be referred to in three places. But, I hope, this is more
than counterbalanced by the completeness of the scheme which results from
the subdivision of the subject.

The pathology of industrial poisoning necessitates frequent repetition
when describing the branches of industry giving rise to the
intoxication, as one and the same form can occur in the most varied
processes. The numerous instances of actual cases of poisoning quoted
must therefore be regarded as conforming to the same pathological type.
Similarly, preventive measures require separate systematic treatment in
order to avoid constant repetition which would otherwise obscure the
general survey. Quite a number of means of prevention apply equally
to several industries in which the same cause is at work. The success
attained by thus simplifying the issues is the greater because such
common measures are the easier to carry through and to supervise.

The method therefore has been adopted only after serious reflection and
has been directed mainly by practical considerations.

Recent cases which have either been reported or come to the knowledge
of the author have been given, with particulars as exact as possible.
Cases dating back some time have been omitted intentionally so as to
exclude everything which did not correspond with the present conditions
of industry and trade. Historical facts only receive consideration in so
far as they are fundamentally important and necessary for the sake of
completeness.

The details given in Part I of actual instances will supply material for
fresh efforts, renewed investigation, and new points of attack.




INDUSTRIAL POISONING




PART I

_DESCRIPTION OF THE INDUSTRIES AND PROCESSES ATTENDED WITH RISK OF
POISONING; INCIDENCE OF SUCH POISONING_




I. THE CHEMICAL INDUSTRY


GENERAL CONSIDERATIONS AS TO INCIDENCE OF INDUSTRIAL POISONING

The chemical industry offers naturally a wide field for the occurrence of
industrial poisoning. Daily contact with the actual poisonous substances
to be prepared, used, stored, and despatched in large quantity gives
opportunity for either acute or chronic poisoning—in the former case
from sudden accidental entrance into the system of fairly large doses,
as the result of defective or careless manipulation, and, in the latter,
constant gradual absorption (often unsuspected) of the poison in small
amount.

The industry, however, can take credit for the way in which incidence
of industrial poisoning has been kept down in view of the magnitude and
variety of the risks which often threaten. This is attributable to the
comprehensive hygienic measures enforced in large chemical works keeping
abreast of modern advance in technical knowledge. A section of this
book deals with the principles underlying these measures. Nevertheless,
despite all regulations, risk of poisoning cannot be wholly banished.
Again and again accidents and illness occur for which industrial
poisoning is responsible. Wholly to prevent this is as impossible as
entirely to prevent accidents by mechanical guarding of machinery.

Owing to the unknown sources of danger, successful measures to ward it
off are often difficult. The rapid advance of this branch of industry,
the constant development of new processes and reactions, the frequent
discovery of new materials (with properties at first unknown, and for a
long time insufficiently understood, but nevertheless indispensable),
constantly give rise to new dangers and possibilities of danger, of which
an accident or some disease with hitherto unknown symptoms is the first
indication. Further, even when the dangerous effects are recognised,
there may often be difficulty in devising appropriate precautions, as
circumstances may prevent immediate recognition of the action of the
poison. We cannot always tell, for instance, with the substances used
or produced in the processes, which is responsible for the poisoning,
because, not infrequently, the substances in question are not chemically
pure, but may be either raw products, bye-products, &c., producing
mixtures of different bodies or liberating different chemical compounds
as impurities.

Hence difficulty often arises in the strict scientific explanation
of particular cases of poisoning, and, in a text-book such as this,
difficulty also of description. A rather full treatment of the technical
processes may make the task easier and help to give a connected picture
of the risks of poisoning in the chemical industry. Such a procedure may
be especially useful to readers insufficiently acquainted with chemical
technology.

We are indebted to Leymann[1] and Grandhomme[2] especially for knowledge
of incidence of industrial poisoning in this industry. The statistical
data furnished by them are the most important proof that poisoning, at
any rate in large factories, is not of very frequent occurrence.

Leymann’s statistics relate to a large modern works in which the number
employed during the twenty-three years of observation increased from
640 in the year 1891 to 1562 in 1904, giving an average of about 1000
yearly, one-half of whom might properly be defined as ‘chemical workers.’
The factory is concerned in the manufacture of sulphuric, nitric, and
hydrochloric acids, alkali, bichromates, aniline, trinitro-phenol,
bleaching powder, organic chlorine compounds, and potassium permanganate.

These statistics are usefully complemented by those of Grandhomme drawn
from the colour works at Höchst a-M. This large aniline works employs
from 2600 to 2700 workers; the raw materials are principally benzene and
its homologues, naphthalene and anthracene. The manufacture includes the
production of coal-tar colours, nitro- and dinitro-benzene, aniline,
rosaniline, fuchsine, and other aniline colours, and finally such
pharmaceutical preparations as antipyrin, dermatol, sanoform, &c. Of the
2700 employed, 1400 are chemical workers and the remainder labourers.

These two series of statistics based on exact observations and covering
allied chemical manufacture are taken together. They seek to give the
answer to the question—How many and what industrial poisonings are found?

The figures of Leymann (on an average of 1000 workers employed per annum)
show 285 cases of poisoning reported between the years 1881 and 1904. Of
these 275 were caused by aniline, toluidine, nitro- and dinitro-benzene,
nitrophenol, nitrochloro and dinitrochloro benzene. Three were fatal
and several involved lengthy invalidity (from 30 to 134 days, owing to
secondary pneumonia). Included further are one severe case of chrome
(bichromate) poisoning (with nephritis as a sequela), five cases of lead
poisoning, three of chlorine, and one of sulphuretted hydrogen gas. In
the Höchst a-M. factory (employing about 2500 workers) there were, in the
ten years 1883-92, only 129 cases of poisoning, of which 109 were due to
aniline. Later figures for the years 1893-5 showed 122 cases, of which 43
were due to aniline and 76 to lead (contracted mostly in the nitrating
house). Grandhomme mentions further hyperidrosis among persons employed
on solutions of calcium chloride, injury to health from inhalation of
methyl iodide vapour in the antipyrin department, a fatal case of benzene
poisoning (entering an empty vessel in which materials had previously
been extracted with benzene), and finally ulceration and perforation of
the septum of the nose in several chrome workers.

The number of severe cases is not large, but it must be remembered that
the factories to which the figures relate are in every respect models
of their kind, amply provided with safety appliances and arrangements
for the welfare of the workers. The relatively small amount of poisoning
is to be attributed without doubt to the precautionary measures taken.
Further, in the statistics referred to only those cases are included
in which the symptoms were definite, or so severe as to necessitate
medical treatment. Absorption of the poison in small amount without
producing characteristic symptoms, as is often the case with irritating
or corrosive fumes, and such as involve only temporary indisposition, are
not included. Leymann himself refers to this when dealing with illness
observed in the mineral acid department (especially sulphuric acid), and
calls attention to the frequency of affections of the respiratory organs
among the persons employed, attributing them rightly to the irritating
and corrosive effect of the acid vapour. Elsewhere he refers to the
frequency of digestive disturbance among persons coming into contact
with sodium sulphide, and thinks that this may be due to the action of
sulphuretted hydrogen gas.

Nevertheless, the effect of industrial poisons on the health of workers
in chemical factories ought on no account to be made light of. The
admirable results cited are due to a proper recognition of the danger,
with consequent care to guard against it. Not only have Grandhomme
and Leymann[A] rendered great services by their work, but the firms
in question also, by allowing such full and careful inquiries to be
undertaken and published.


SULPHURIC ACID (SULPHUR DIOXIDE)

MANUFACTURE.—Sulphur dioxide, generally obtained by roasting pyrites in
furnaces of various constructions, or, more rarely, by burning brimstone
or sulphur from the spent oxide of gas-works, serves as the raw material
for the manufacture of sulphuric acid. Before roasting the pyrites is
crushed, the ‘lump ore’ then separated from the ‘smalls,’ the former
roasted in ‘lump-burners’ or kilns (generally several roasting furnace
hearths united into one system), and the latter preferably in Malétra and
Malétra-Schaffner shelf-burners (fig. 1) composed of several superimposed
firebrick shelves. The pyrites is charged on to the uppermost shelf and
gradually worked downwards. Pyrites residues are not suitable for direct
recovery of iron, but copper can be recovered from residues sufficiently
rich in metal by the wet process; the residues thus freed of copper and
sulphur are then smelted for recovery of iron.

[Illustration: FIG. 1.—Pyrites Burner for Smalls (_after Lueger_)]

Utilisation for sulphuric acid manufacture of the sulphur dioxide given
off in the calcining of zinc blende (see Spelter works), impracticable in
reverberatory furnaces, has been made possible at the Rhenania factory by
introduction of muffle furnaces (several superimposed), because by this
means the gases led off are sufficiently concentrated, as they are not
diluted with the gases and smoke from the heating fires. This method,
like any other which utilises the gases from roasting furnaces, has
great hygienic, in addition to economical, advantages, because escape
of sulphur dioxide gas is avoided. Furnace gases, too poor in sulphur
dioxide to serve for direct production of sulphuric acid, can with
advantage be made to produce liquid anhydrous sulphur dioxide. Thus, the
sulphur dioxide gas from the furnaces is first absorbed by water, driven
off again by boiling, cooled, dried, and liquefied by pressure.

The gaseous sulphur dioxide obtained by any of the methods described is
converted into sulphuric acid either by (_a_) the chamber process or
(_b_) the contact process.

In the _lead chamber process_ the furnace gases pass through flues in
which the flue dust and a portion of the arsenious acid are deposited
into the Glover tower at a temperature of about 300° C., and from there
into the lead chambers where oxidation of the sulphur dioxide into
sulphuric acid takes place, in the presence of sufficient water, by
transference of the oxygen of the air through the intervention of the
oxides of nitrogen. The gases containing oxides of nitrogen, &c., which
are drawn out of the lead chambers, have the nitrous fumes absorbed
in the Gay-Lussac tower (of which there are one or two in series), by
passage through sulphuric acid which is made to trickle down the tower.
The sulphuric acid so obtained, rich in oxides of nitrogen, and the
chamber acid are led to the Glover tower for the purpose of denitration
and concentration, so that all the sulphuric acid leaves the Glover
as Glover acid of about 136-144° Tw. Losses in nitrous fumes are best
made up by addition of nitric acid at the Glover or introduction into
the first chamber. The deficiency is also frequently made good from
nitre-pots.

The lead chambers (fig. 2) are usually constructed entirely—sides,
roof, and floor—of lead sheets, which are joined together by means of a
hydrogen blowpipe. The sheets forming the roof and walls are supported,
independent of the bottom, on a framework of wood. The capacity varies
from 35,000 to 80,000 cubic feet. The floor forms a flat collecting
surface for the chamber acid which lutes the chamber from the outer air.
The necessary water is introduced into the chamber as steam or fine water
spray.

The Glover and Gay-Lussac towers are lead towers. The Glover is lined
with acid-proof bricks and filled with acid-proof packing to increase
the amount of contact. The Gay-Lussac is filled with coke over which
the concentrated sulphuric acid referred to above flows, forming, after
absorption of the nitrous fumes, nitro-sulphuric acid.

[Illustration: FIG. 2A.—Lead Chamber System—Section through X X (_after
Ost_)

FIG. 2B.—Lead Chamber System—Plan

    A Pyrites Burner
    B Glover Tower
    C Draft Regulator
    D, D´ Lead Chambers
    E Air Shaft
    F, F,´ F,´´ F´´´ Acid Reservoirs
    G Acid Egg
    H Cooler
    J Gay-Lussac Tower]

As already stated, two Gay-Lussac towers are usually connected together,
or where there are several lead-chamber systems there is, apart from the
Gay-Lussac attached to each, a central Gay-Lussac in addition, common
to the whole series. The introduction of several Gay-Lussac towers
has the advantage of preventing loss of the nitrous fumes as much as
possible—mainly on economical grounds, as nitric acid is expensive. But
this arrangement is at the same time advantageous on hygienic grounds, as
escape of poisonous gases containing nitrous fumes, &c., is effectually
avoided. The acids are driven to the top of the towers by compressed air.
The whole system—chambers and towers—is connected by means of wide lead
conduits. Frequently, for the purpose of quickening the chamber process
(by increasing the number of condensing surfaces) Lunge-Rohrmann plate
towers are inserted in the system—tall towers lined with lead in which
square perforated plates are hung horizontally, and down which diluted
sulphuric acid trickles.

To increase the draught in the whole system a chimney is usual at
the end, and, in addition, a fan of hard lead or earthenware may be
introduced in front of the first chamber or between the two Gay-Lussac
towers. Maintenance of a constant uniform draught is not only necessary
for technical reasons, but has hygienic interest, since escape of
injurious gases is avoided (see also Part III).

The chamber acid (of 110°-120° Tw. = 63-70 %) and the stronger Glover
acid (of 136°-144° Tw. = 75-82 %) contain impurities. In order to obtain
for certain purposes pure strong acid the chamber acid is purified and
concentrated. The impurities are notably arsenious and nitrous acids
(Glover acid is N free), lead, copper, and iron. Concentration (apart
from that to Glover acid in the Glover tower) is effected by evaporation
in lead pans to 140° Tw. and finally in glass balloons or platinum stills
to 168° Tw. (= 97 %). The lead pans are generally heated by utilising the
waste heat from the furnaces or by steam coils in the acid itself, or
even by direct firing.

Production of sulphuric acid by the _contact method_ depends on the fact
that a mixture of sulphur dioxide and excess of oxygen (air) combines
to form sulphur trioxide at a moderate heat in presence of a contact
substance such as platinised asbestos or oxide of iron. The sulphur
dioxide must be carefully cleaned and dried, and with the excess of air
is passed through the contact substance. If asbestos carrying a small
percentage of finely divided platinum is the contact substance, it is
generally used in the form of pipes; oxide of iron (the residue of
pyrites), if used, is charged into a furnace. Cooling by a coil of pipes
and condensation in washing towers supplied with concentrated sulphuric
acid always forms a part of the process. A fan draws the gases from the
roasting furnaces and drives them through the system. The end product
is a fuming sulphuric acid containing 20-30 per cent. SO₃. From this by
distillation a concentrated acid and a pure anhydride are obtained. From
a health point of view it is of importance to know that all sulphuric
acid derived from this anhydride is pure and free from arsenic.

The most important _uses_ of sulphuric acid are the following: as chamber
acid (110°-120° Tw.) in the superphosphate, ammonium sulphate, and alum
industries; as Glover acid (140°-150° Tw.) in the Leblanc process, i.e.
saltcake and manufacture of hydrochloric acid, and to etch metals; as
sulphuric acid of 168° Tw. in colour and explosives manufacture (nitric
acid, nitro-benzene, nitro-glycerine, gun-cotton, &c.); as concentrated
sulphuric acid and anhydride for the production of organic sulphonic
acids (for the alizarin and naphthol industry) and in the refining of
petroleum and other oils. Completely de-arsenicated sulphuric acid
is used in making starch, sugar, pharmaceutical preparations, and in
electrical accumulator manufacture.

EFFECTS ON HEALTH.—The health of sulphuric acid workers cannot in general
be described as unfavourable.

In comparison with chemical workers they have, it is said, relatively
the lowest morbidity. Although in this industrial occupation no
special factors are at work which injure in general the health of the
workers, there is a characteristic effect, without doubt due to the
occupation—namely, disease of the respiratory organs. Leymann’s figures
are sufficiently large to show that the number of cases of diseases
of the respiratory organs is decidedly greater in the sulphuric acid
industry than among other chemical workers. He attributes this to the
irritating and corrosive effect of sulphur dioxide and sulphuric acid
vapour on the mucous membrane of the respiratory tract, as inhalation
of these gases can never be quite avoided, because the draught in the
furnace and chamber system varies, and the working is not always uniform.
Strongly irritating vapours escape again in making a high percentage
acid in platinum vessels, which in consequence are difficult to keep
air-tight. Of greater importance than these injurious effects from
frequent inhalation of small quantities of acid vapours, or employment
in workrooms in which the air is slightly charged with acid, is the
accidental sudden inhalation of large quantities of acid gases, which may
arise in the manufacture, especially by careless attendance. Formerly
this was common in charging the roasting furnaces when the draught in the
furnace, on addition of the pyrites, was not strengthened at the same
time. This can be easily avoided by artificial regulation of the draught.

Accidents through inhalation of acid gases occur further when entering
the lead chambers or acid tanks, and in emptying the towers. Heinzerling
relates several cases taken from factory inspectors’ reports. Thus, in a
sulphuric acid factory the deposit (lead oxysulphate) which had collected
on the floor of a chamber was being removed: to effect this the lead
chambers were opened at the side. Two of the workers, who had probably
been exposed too long to the acid vapours evolved in stirring up the
deposit, died a short time after they had finished the work. A similar
fatality occurred in cleaning out a nitro-sulphuric acid tank, the
required neutralisation of the acid by lime before entering having been
omitted. Of the two workers who entered, one died the next day; the other
remained unaffected. The deceased had, as the post mortem showed, already
suffered previously from pleurisy. A fatality from breathing nitrous
fumes is described fully in the report of the Union of Chemical Industry
for the year 1905. The worker was engaged with two others in fixing a fan
to a lead chamber; the workers omitted to wait for the arrival of the
foreman who was to have supervised the operation. Although the men used
moist sponges as respirators, one of them inhaled nitrous fumes escaping
from the chamber in such quantity that he died the following day.

Similar accidents have occurred in cleaning out the Gay-Lussac towers.
Such poisonings have repeatedly occurred in Germany. Fatal poisoning is
recorded in the report of the Union of Chemical Industry, in the emptying
and cleaning of a Gay-Lussac tower despite careful precautions. The
tower, filled with coke, had been previously well washed with water, and
during the operation of emptying, air had been constantly blown through
by means of a Körting’s injector. The affected worker had been in the
tower about an hour; two hours later symptoms of poisoning set in which
proved fatal in an hour despite immediate medical attention. As such
accidents kept on recurring, the Union of Chemical Industry drew up
special precautions to be adopted in the emptying of these towers, which
are printed in Part III.

Naturally, in all these cases it is difficult to say exactly which of the
acid gases arising in the production of sulphuric acid was responsible
for the poisoning. In the fatal cases cited, probably nitrous fumes
played the more important part.

Poisoning has occurred in the transport of sulphuric acid. In some of
the cases, at all events, gaseous impurities, especially arseniuretted
hydrogen, were present.

Thus, in the reports of the German Union of Chemical Industry for the
year 1901, a worker succumbed through inhalation of poisonous gases in
cleaning out a tank waggon for the transport of sulphuric acid. The tank
was cleaned of the adhering mud, as had been the custom for years, by a
man who climbed into it. No injurious effects had been noted previously
at the work, and no further precautions were taken than that one worker
relieved another at short intervals, and the work was carried on under
supervision. On the occasion in question, however, there was an unusually
large quantity of deposit, although the quality of the sulphuric acid was
the same, and work had to be continued longer. The worker who remained
longest in the tank became ill on his way home and died in hospital
the following day; the other workers were only slightly affected. The
sulphuric acid used by the firm in question immediately before the
accident came from a newly built factory in which anhydrous sulphuric
acid had been prepared by a special process. The acid was Glover acid,
and it is possible that selenium and arsenic compounds were present
in the residues. Arseniuretted hydrogen might have been generated in
digging up the mud. Two similar fatalities are described in the report of
the same Union for the year 1905. They happened similarly in cleaning out
a sulphuric acid tank waggon, and in them the arsenic in the acid was the
cause. Preliminary swilling out with water diluted the remainder of the
sulphuric acid, but, nevertheless, it acted on the iron of the container.
Generation of hydrogen gas is the condition for the reduction of the
arsenious acid present in sulphuric acid with formation of arseniuretted
hydrogen. In portions of the viscera arsenic was found. Lately in the
annual reports of the Union of Chemical Industry for 1908 several cases
of poisoning are described which were caused by sulphuric acid. A worker
took a sample out of a vessel of sulphuric acid containing sulphuretted
hydrogen gas. Instead of using the prescribed cock, he opened the
man-hole and put his head inside, inhaling concentrated sulphuretted
hydrogen gas. He became immediately unconscious and died. Through
ignorance no use was made of the oxygen apparatus.

Another fatality occurred through a foreman directing some workers,
contrary to the regulations against accidents from nitrous gases, to
clean a vessel containing nitric and sulphuric acids. They wore no air
helmets: one died shortly after from inhalation of nitrous fumes. Under
certain circumstances even the breaking of carboys filled with sulphuric
acid may give rise to severe poisoning through inhalation of acid gases.
Thus a fatality[1] occurred to the occupier of a workroom next some
premises in which sulphuric acid carboys had been accidentally broken.
Severe symptoms developed the same night, and he succumbed the next
morning in spite of treatment with oxygen. A worker in the factory became
seriously ill but recovered.

A similar case is described[2] in a factory where concentrated sulphuric
acid had been spilt. The workers covered the spot with shavings,
which resulted in strong development of sulphur dioxide, leading to
unconsciousness in one worker.

The frequent observation of the injurious effect of acid gases on the
teeth of workers requires mention; inflammation of the eyes of workers
also is attributed to the effects of sulphuric acid.

Leymann’s statistics show _corrosions and burns_ among sulphuric acid
workers to be more than five times that among other classes. Such burns
happen most frequently from carelessness. Thus, in the reports of the
Union of Chemical Industry for 1901, three severe accidents are mentioned
which occurred from use of compressed air. In two cases the acid had been
introduced before the compressed air had been turned off; in the third
the worker let the compressed air into the vessel and forgot to turn off
the inlet valve. Although the valves were provided with lead guards,
some of the acid squirted into the worker’s face. In one case complete
blindness followed, in a second blindness in one eye, and in the third
blindness in one eye and impaired vision of the other.

Besides these dangers from the raw material, bye-products, and products
of the manufacture, _lead poisoning_ has been reported in the erection
and repair of lead chambers. The lead burners generally use a hydrogen
flame; the necessary hydrogen is usually made from zinc and sulphuric
acid and is led to the iron by a tube. If the zinc and sulphuric acid
contain arsenic, the very dangerous arseniuretted hydrogen is formed,
which escapes through leakages in the piping, or is burnt in the flame to
arsenious acid.

Further, the lead burners and plumbers are exposed to the danger of
chronic lead poisoning from insufficient observance of the personal
precautionary measures necessary to guard against it (see Part III).
Those who are constantly engaged in burning the lead sheets and pipes of
the chambers suffer not infrequently from severe symptoms. Unfortunately,
the work requires skill and experience, and hence alternation of
employment is hardly possible.

Finally, mention should be made of poisoning by _arseniuretted hydrogen
gas_ from vessels filled with sulphuric acid containing arsenic as an
impurity, and by sulphuretted hydrogen gas in purifying the acid itself.
In the manufacture of liquid _sulphur dioxide_, injury to health can
arise from inhalation of the acid escaping from the apparatus. The most
frequent cause for such escape of sulphur dioxide is erosion of the walls
of the compressor pumps and of the transport vessels, in consequence of
the gas being insufficiently dried, as, when moist, it attacks iron.

Sulphur dioxide will come up for further consideration when describing
the industrial processes giving rise to it, or in which it is used.


HYDROCHLORIC ACID, SALTCAKE, AND SODA

MANUFACTURE.—The production of hydrochloric acid (HCl), sodium sulphate
(Na₂SO₄), and sodium sulphide (Na₂S) forms part of the manufacture of
soda (Na₂CO₃) by the Leblanc process. The products first named increase
in importance, while the Leblanc soda process is being replaced more and
more by the manufacture of soda by the Solvay ammonia process, so much so
that on the Continent the latter method predominates and only in England
does the Leblanc process hold its ground.

Health interests have exercised an important bearing on the development
of the industries in question. At first, in the Leblanc process the
hydrochloric acid gas was allowed to escape into the atmosphere, being
regarded as a useless bye-product. Its destructive action on plant
life and the inconvenience caused to the neighbourhood, in spite of
erection of high chimneys, demanded intervention. In England the evils
led to the enactment of the Alkali Acts—the oldest classical legislative
measures bearing on factory hygiene—by which the Leblanc factories were
required to condense the vapour by means of its absorption in water, and
this solution of the acid is now a highly valued product. And, again,
production of nuisance—inconvenience to the neighbourhood through the
soda waste—was the main cause of ousting one of the oldest and most
generally used methods of chemical industrial production. Although every
effort was made to overcome the difficulties, the old classical Leblanc
process is gradually but surely yielding place to the modern Solvay
process, which has no drawback on grounds of health.

We outline next the main features of the _Leblanc soda process_, which
includes, as has been mentioned, also the manufacture of hydrochloric
acid, sodium sulphate and sulphide.

The first part of the process consists in the production of the sulphate
from salt and sulphuric acid, during which hydrochloric acid is formed;
this is carried out in two stages represented in the following formulæ:

    1. NaCl + H₂SO₄ = NaHSO₄ + HCl.
    2. NaCl + NaHSO₄ = Na₂SO₄ + HCl.

The first stage in which bisulphate is produced is carried out at a
moderate heat, the second requires a red heat. The reactions, therefore,
are made in a furnace combining a pan and muffle furnace.

This saltcake muffle furnace is so arranged that the pan can be shut
off from the muffle by a sliding-door (D). The pan (A) and muffle (E)
have separate flues for carrying off the hydrochloric acid developed (B,
F). First, common salt is treated with sulphuric (Glover) acid in the
cast-iron pan. When generation of hydrochloric acid vapour has ceased,
the sliding-door is raised and the partly decomposed mixture is pushed
through into the muffle, constructed of fire-resisting bricks and tiles,
and surrounded by the fire gases. While the muffle is being raised to
red heat, the sulphate must be repeatedly stirred with a rake in order,
finally, while still hot and giving off acid vapour, to be drawn out at
the working doors into iron boxes provided with doors, where the material
cools. The acid vapour given off when cooling is drawn through the top of
the box into the furnace.

[Illustration: FIG. 3.—Saltcake Muffle Furnace—Section _(after Ost_)

A Pan; B, F Pipes for hydrochloric acid vapour; D Shutter; E Muffle, O
Coke fire.]

Mechanical stirrers, despite their advantage from a health point of view,
have not answered because of their short life.

The valuable bye-product of the sulphate process, _hydrochloric acid_, is
led away separately from the pan and the muffle, as is seen, into one
absorption system. The reason of the separation is that the gas from the
pan is always the more concentrated. The arrangement of the absorbing
apparatus is illustrated in fig. 4.

[Illustration: FIG. 4A.—Preparation of Hydrochloric Acid—Plan (_after
Lueger_)

    A, A´ Earthenware pipes
    B, B´ Sandstone cooling towers
    C, C Series of Woulff’s bottles
    D, E Condenser wash towers

FIG. 4B.—Elevation]

The gases are led each through earthenware pipes or channels of stone
pickled with tar (A´), first into small towers of Yorkshire flags (B),
where they are cooled and freed from flue dust and impurities (sulphuric
acid) by washing. They are next led through a series (over fifty) of
Woulff bottles (bombonnes) one metre high, made of acid-resisting
stoneware. The series is laid with a slight inclination towards the
furnace, and water trickles through so that the gases coming from the
wash towers are brought into contact with water in the one case already
almost saturated, whilst the gas which is poorest in hydrochloric acid
meets with fresh water. From the bombonne situated next to the wash tower
the prepared acid is passed as a rule through another series. The last
traces of hydrochloric acid are then removed by leading the gases from
the Woulff bottles up two water towers of stoneware (D and E), which are
filled partly with earthenware trays and partly with coke; above are
tanks from which the water trickles down over the coke. The residual
gases from both sets of absorbing apparatus now unite in a large Woulff
bottle before finally being led away through a duct to the chimney stack.

Less frequently absorption of hydrochloric acid is effected without use
of Woulff bottles, principally in wash towers such as the Lunge-Rohrmann
plate tower.

In the purification of hydrochloric acid, de-arsenicating by sulphuretted
hydrogen or by barium sulphide, &c., and separation of sulphuric acid by
addition of barium chloride, have to be considered.

Another method for production of sulphate and hydrochloric acid, namely,
the Hargreaves process, is referred to later.

We return now to the further working up of the sodium sulphate into
sulphide and soda. The conversion of the sulphate into soda by the
Leblanc method is effected by heating with coal and calcium carbonate,
whereby, through the action of the coal, sodium sulphide forms first,
which next with the calcium carbonate becomes converted into sodium
carbonate and calcium sulphide.

The reactions are:

    Na₂SO₄ + 2C = Na₂S + 2CO₂
    Na₂S + CaCO₃ = Na₂CO₃ + CaS
    CaCO₃ + C = CaO + 2CO.

The reactions are carried out in small works in open reverberatory
furnaces having two platforms on the hearth, and with continuous raking
from one to the other which, as the equations show, cause escape of
carbonic acid gas and carbonic oxide.

Such handworked furnaces, apart from their drawbacks on health grounds,
have only a small capacity, and in large works their place is taken by
revolving furnaces—closed, movable cylindrical furnaces—in which handwork
is replaced by the mechanical revolution of the furnace and from which a
considerably larger output and a product throughout good in quality are
obtained.

The _raw soda_ thus obtained in the black ash furnace is subjected to
lixiviation by water in iron tanks in which the impurities or tank
waste (see below) are deposited. The crude soda liquor so obtained is
then further treated and converted into calcined soda, crystal soda, or
caustic soda. In the production of calcined soda the crude soda liquor is
first purified (‘oxidised’ and ‘carbonised’) by blowing through air and
carbonic acid gas, pressed through a filter press, and crystallised by
evaporation in pans and calcined, i.e. deprived of water by heat.

[Illustration: FIG. 5.—Revolving Black Ash Furnace—Elevation (_after
Lueger_)

A Firing hearth; B Furnace; C Dust box.]

_Crystal soda_ is obtained from well-purified tank liquor by
crystallising in cast-iron vessels.

Caustic soda is obtained by introducing lime suspended in iron cages into
the soda liquor in iron caustic pots, heating with steam, and agitating
by blowing in air.

The resulting clear solution is drawn off and evaporated in cast-iron
pans.

As already mentioned, the _tank waste_ in the Leblanc process, which
remains behind—in amount about equal to the soda produced after
lixiviation of the raw soda with water—constitutes a great nuisance.
It forms mountains round the factories, and as it consists principally
of calcium sulphide and calcium carbonate, it easily weathers under
the influence of air and rain, forming soluble sulphur compounds and
developing sulphuretted hydrogen gas—an intolerable source of annoyance
to the district.

At the same time all the sulphur introduced into the industry as
sulphuric acid is lost in the tank waste. This loss of valuable material
and the nuisance created led to attempts—partially successful—to recover
the sulphur.

The best results are obtained by the Chance-Claus method, in which the
firebrick ‘Claus-kiln’ containing ferric oxide (previously heated to
dull redness) is used. In this process calcium sulphide is acted on by
carbonic acid with evolution of gas so rich in sulphuretted hydrogen that
it can be burnt to sulphur dioxide and used in the lead chambers for
making sulphuric acid. Sulphur also as such is obtained by the method.

These sulphur-recovery processes which have hardly been tried on
the Continent—only the United Alkali Company in England employs the
Chance-Claus on a large scale—were, as has been said, not in a position
to prevent the downfall of the Leblanc soda industry. Before describing
briefly the Solvay method a word is needed as to other processes for
manufacture of sulphate and hydrochloric acid.

_Hargreaves’ process_ produces sodium sulphate (without previous
conversion of sulphur dioxide into sulphuric acid) directly by the
passage of gases from the pyrites burners, air and steam, through salt
blocks placed in vertical cast-iron retorts, a number of which are
connected in series. A fan draws the gases through the system and leads
the hydrochloric acid fumes to the condenser.

Sodium sulphate is used in the manufacture of glass, ultramarine, &c.
Further, the sulphate is converted into Glauber’s salts by dissolving the
anhydrous sulphate obtained in the muffle furnace, purifying with lime,
and allowing the clear salt solution to crystallise out in pans.

A further use of the sulphate is the preparation of sodium sulphide,
which is effected (as in the first part of the Leblanc soda process) by
melting together sulphate and coal in a reverberatory furnace. If the
acid sulphate (bisulphate) or sulphate containing bisulphate is used much
sulphur dioxide gas comes off.

The mass is then lixiviated in the usual soda liquor vats and the lye
either treated so as to obtain crystals or evaporated to strong sodium
sulphide which is poured like caustic soda into metal drums where it
solidifies.

In _Solvay’s ammonia soda process_ ammonia recovered from the waste
produced in the industry is led into a solution of salt until saturation
is complete. This is effected generally in column apparatus such as is
used in distillation of spirit. The solution is then driven automatically
by compressed air to the carbonising apparatus in which the solution
is saturated with carbonic acid; this apparatus is a cylindrical tower
somewhat similar to the series of vessels used for saturating purposes in
sugar factories through which carbonic acid gas passes. In this process
crystalline bi-carbonate of soda is first formed, which is separated
from the ammoniacal mother liquor by filtration, centrifugalisation,
and washing. The carbonate is then obtained by heating (calcining in
pans), during which carbonic acid gas escapes, and this, together with
the carbonic acid produced in the lime kilns, is utilised for further
carbonisation again. The lime formed during the production of carbonic
acid in the lime kilns serves to drive the ammonia out of the ammoniacal
mother liquor, so that the ammonia necessary for the process is recovered
and used over and over again. The waste which results from the action of
the lime on the ammonium chloride liquor is harmless—calcium chloride
liquor.

The _electrolytic_ manufacture of soda from salt requires mention, in
which chlorine (at the anode) and caustic soda (at the cathode) are
formed; the latter is treated with carbonic acid to make soda.

EFFECTS ON HEALTH.—Leymann’s observations show that in the department
concerned with the Leblanc soda process and production of sodium
sulphide, relatively more sickness is noted than, for example, in the
manufacture of sulphuric and nitric acids.

In the preparation of the sulphate, possibility of injury to health or
poisoning arises from the fumes containing hydrochloric or sulphuric acid
in operations at the muffle furnace; in Hargreaves’ process there may be
exposure to the effect of sulphur dioxide. Hydrochloric and sulphuric
acid vapours can escape from the muffle furnace when charging, from
leakages in it, and especially when withdrawing the still hot sulphate.
Large quantities of acid vapours escape from the glowing mass, especially
if coal is not added freely and if it is not strongly calcined. Persons
employed at the saltcake furnaces suffer, according to Jurisch, apart
from injury to the lungs, from defective teeth. The teeth of English
workers especially, it is said, from the practice of holding flannel in
their mouths with the idea of protecting themselves from the effect of
the vapours, are almost entirely eroded by the action of the hydrochloric
acid absorbed by the saliva. Hydrochloric acid vapour, further, can
escape from the absorbing apparatus if this is not kept entirely
sealed, and the hydrochloric acid altogether absorbed—a difficult
matter. Nevertheless, definite acute industrial poisoning from gaseous
hydrochloric acid is rare, no doubt because the workers do not inhale it
in concentrated form.

Injury to the skin from the acid absorbed in water may occur in filling,
unloading, and transport, especially when in carboys, but the burns,
if immediately washed, are very slight in comparison with those from
sulphuric or nitric acids. Injury to health or inconvenience from
sulphuretted hydrogen is at all events possible in the de-arsenicating
process by means of sulphuretted hydrogen gas. At the saltcake furnace
when worked by hand the fumes containing carbonic oxide gas may be
troublesome. In the production of caustic soda severe corrosive action on
the skin is frequent. Leymann found that 13·8 per cent. of the persons
employed in the caustic soda department were reported as suffering from
burns, and calls attention to the fact that on introducing the lime
into the hot soda lye the contents of the vessel may easily froth over.
Heinzerling refers to the not infrequent occurrence of eye injuries in
the preparation of caustic soda, due to the spurting of lye or of solid
particles of caustic soda.

The tank waste gives rise, as already stated, to inconvenience from the
presence of sulphuretted hydrogen. In the recovery of the sulphur and
treatment of the tank waste, sulphuretted hydrogen and sulphur dioxide
gases are evolved. According to Leymann, workers employed in removing
the waste and at the lye vats frequently suffer from inflammation of
the eyes. Further, disturbance of digestion has been noted in persons
treating the tank waste, which Leymann attributes to the unavoidable
development of sulphuretted hydrogen gas.

In the manufacture of sodium sulphide similar conditions prevail. Leymann
found in this branch relatively more cases of sickness than in any other;
diseases of the digestive tract especially appeared to be more numerous.
Leymann makes the suggestion that occurrence of disease of the digestive
organs is either favoured by sodium sulphide when swallowed as dust, or
that here again sulphuretted hydrogen gas plays a part. Further corrosive
effect on the skin and burns may easily arise at work with the hot
corrosive liquor.

In the Solvay ammonia process ammonia and carbonic acid gas are present,
but, so far as I know, neither injury to health nor poisoning have been
described among persons employed in the process. Indeed, the view is
unanimous that this method of manufacture with its technical advantages
has the merit also of being quite harmless. As may be seen from the
preceding description of the process there is no chance of the escape of
the gases named into the workrooms.


USE OF SULPHATE AND SULPHIDE

_Ultramarine_ is made from a mixture of clay, sulphate (Glauber’s
salts), and carbon—sulphate ultramarine; or clay, sulphur, and
soda—soda ultramarine. These materials are crushed, ground, and burnt
in muffle furnaces. On heating the mass in the furnace much sulphur
dioxide escapes, which is a source of detriment to the workmen and the
neighbourhood.

_Sulphonal_ (CH₃)₂C(SO₂C₂H₅)₂, diethylsulphone dimethylmethane,
used medically as a hypnotic, is obtained from mercaptan formed by
distillation of ethyl sulphuric acid with sodium or potassium sulphide.
The mercaptan is converted into mercaptol, and this by oxidation with
potassium permanganate into sulphonal. The volatile mercaptan has a most
disgusting odour, and clings for a long time even to the clothes of those
merely passing through the room.

_Diethyl sulphate_ ((C₂H₅)₂SO₄).—Diethyl sulphate obtained by the
action of sulphuric acid on alcohol has led to poisoning characterised
by corrosive action on the respiratory tract.[1] As the substance in
the presence of water splits up into sulphuric acid and alcohol, this
corrosive action is probably due to the acid. It is possible, however,
that the molecule of diethyl sulphate as such has corrosive action.

Contact with diethyl sulphate is described as having led to fatal
poisoning.[2]

A chemist when conducting a laboratory experiment dropped a glass flask
containing about 40 c.c. of diethyl sulphate, thereby spilling some over
his clothes. He went on working, and noticed burns after some time,
quickly followed by hoarseness and pain in the throat. He died of severe
inflammation of the lungs. A worker in another factory was dropping
diethyl sulphate and stirring it into an at first solid, and later
semi-liquid, mass for the purpose of ethylating a dye stuff. In doing
so he was exposed to fumes, and at the end of the work complained of
hoarseness and smarting of the eyes. He died of double pneumonia two days
later. Post mortem very severe corrosive action on the respiratory tract
was found, showing that the diethyl sulphuric acid had decomposed inside
the body and that nascent sulphuric acid had given rise to the severe
burns. The principal chemist who had superintended the process suffered
severely from hoarseness at night, but no serious consequences followed.

It is stated also that workmen in chemical factories coming into contact
with the fumes of diethyl sulphate ester suffer from eye affections.[3]


CHLORINE, CHLORIDE OF CALCIUM, AND CHLORATES

MANUFACTURE.—The older processes depend on the preparation of chlorine
and hydrochloric acid by an oxidation process in which the oxidising
agent is either a compound rich in oxygen—usually common manganese
dioxide (pyrolusite)—or the oxygen of the air in the presence of heated
copper chloride (as catalytic agent). The former (Weldon process) is
less used now than either the latter (Deacon process) or the electrolytic
manufacture of chlorine.

In the _Weldon process_ from the still liquors containing manganous
chloride the manganese peroxide is regenerated, and this so regenerated
Weldon mud, when mixed with fresh manganese dioxide, is used to initiate
the process. This is carried out according to the equations:

    MnO₂ + 4HCl = MnCl₄ + 2H₂O
          MnCl₄ = MnCl₂ + Cl₂.

[Illustration: FIG. 6.—Preparation of Chlorine—Diaphragm Method (_after
Ost_)]

Hydrochloric acid is first introduced into the chlorine still (vessels
about 3 m. in height, of Yorkshire flag or fireclay), next the Weldon
mud gradually, and finally steam to bring the whole to boiling; chlorine
comes off in a uniform stream. The manganous chloride still liquor is run
into settling tanks. The regeneration of the manganous chloride liquor
takes place in an oxidiser which consists of a vertical iron cylinder in
which air is blown into the heated mixture of manganous chloride and milk
of lime. The dark precipitate so formed, ‘Weldon mud,’ as described, is
used over again, while the calcium chloride liquor runs away.

The _Deacon process_ depends mainly on leading the stream of hydrochloric
acid gas evolved from a saltcake pot mixed with air and heated into a
tower containing broken bricks of the size of a nut saturated with
copper chloride. Chlorine is evolved according to the equation:

    2HCl + O = 2Cl + H₂O.

[Illustration: FIG. 7.—Preparation of Chlorine—Bell Method (_after Ost_)]

The _electrolytic production_ of chlorine with simultaneous production
of _caustic alkali_ is increasing and depends on the splitting up of
alkaline chlorides by a current of electricity. The chlorine evolved at
the anode and the alkaline liquor formed at the cathode must be kept
apart to prevent secondary formation of hypochlorite and chlorate (see
below). This separation is generally effected in one of three ways: (1)
In the diaphragm process (Griesheim-Elektron chemical works) the anode
and cathode are kept separate by porous earthenware diaphragms arranged
as illustrated in fig. 6. The anode consists of gas carbon, or is made
by pressing and firing a mixture of charcoal and tar; it lies inside the
diaphragm. The chlorine developed in the anodal cell is carried away by
a pipe. The metal vessel serves as the cathode. The alkali, which, since
it contains chloride, is recovered as caustic soda after evaporation
and crystallisation, collects in the cathodal space lying outside the
diaphragm. (2) By the Bell method (chemical factory at Aussig) the
anodal and cathodal fluids, which keep apart by their different specific
weights, are separated by a stoneware bell; the poles consist of sheet
iron and carbon. The containing vessel is of stoneware. (3) In the
mercury process (England) sodium chloride is electrolysed without a
diaphragm, mercury serving as the cathode. This takes up the sodium,
which is afterwards recovered from the amalgam formed by means of water.

If _chlorate_ or _hypochlorite_ is to be obtained electrolytically,
electrodes of the very resistant but expensive platinum iridium are used
without a diaphragm. Chlorine is developed—not free, but combined with
the caustic potash. The bleaching fluid obtained electrolytically in this
way is a rival of bleaching powder.

_Bleaching powder_ is made from chlorine obtained by the Weldon or Deacon
process. Its preparation depends on the fact that calcium hydrate takes
up chlorine in the cold with formation of calcium hypochlorite after the
equation:

    2Ca(OH)₂ + 4Cl = Ca(ClO)₂ + CaCl₂ + 2H₂O.

The resulting product contains from 35 to 36 per cent. chlorine, which is
given off again when treated with acids.

The preparation of chloride of lime takes place in bleaching powder
chambers made of sheets of lead and Yorkshire flagstones. The lime is
spread out on the floors of these and chlorine introduced. Before the
process is complete the lime must be turned occasionally.

In the manufacture of bleaching powder from Deacon chlorine, Hasenclever
has constructed a special cylindrical apparatus (fig. 8), consisting of
several superimposed cast-iron cylinders in which are worm arrangements
carrying the lime along, while chlorine gas passes over in an opposite
direction. This continuous process is, however, only possible for the
Deacon chlorine strongly diluted with nitrogen and oxygen and not for
undiluted Weldon gas.

_Liquid chlorine_ can be obtained by pressure and cooling from
concentrated almost pure Weldon chlorine gas.

_Potassium chlorate_, which, as has been said, is now mostly obtained
electrolytically, was formerly obtained by passing Deacon chlorine into
milk of lime and decomposing the calcium chlorate formed by potassium
chloride.

Chlorine and chloride of lime are used for bleaching; chlorine further
is used in the manufacture of colours; chloride of lime as a mordant in
cloth printing and in the preparation of chloroform; the chlorates are
oxidising agents and used in making safety matches. The manufacture of
organic chlorine products will be dealt with later.

[Illustration: FIG. 8.—Preparation of Bleaching Powder. Apparatus of
Hasenclever (_after Ost_)

A Hopper for slaked lime; W Worm conveying lime; Z Toothed wheels;
K Movable covers; C Entrance for chlorine gas; D Pipe for escape of
chlorine-free gas; B Outlet shoot for bleaching powder]

EFFECTS ON HEALTH.—In these industries the possibility of injury to
health and poisoning by inhalation of chlorine gas is prominent. Leymann
has shown that persons employed in the manufacture of chlorine and
bleaching powder suffer from diseases of the respiratory organs 17·8 per
cent., as contrasted with 8·8 per cent. in other workers: and this is
without doubt attributable to the injurious effect of chlorine gas, which
it is hardly possible to avoid despite the fact that Leymann’s figures
refer to a model factory. But the figures show also that as the industry
became perfected the number of cases of sickness steadily diminished.

Most cases occur from unsatisfactory conditions in the production of
chloride of lime, especially if the chloride of lime chambers leak, if
the lime is turned over while the chlorine is being let in, by too early
entrance into chambers insufficiently ventilated, and by careless and
unsuitable methods of emptying the finished bleaching powder.

The possibility of injury is naturally greater from the concentrated gas
prepared by the Weldon process than from the diluted gas of the Deacon
process—the more so as in the latter the bleaching powder is made in
the Hasenclever closed-in cylindrical apparatus in which the chlorine
is completely taken up by the lime. The safest process of all is the
electrolytic, as, if properly arranged, there should be no escape of
chlorine gas. The chlorine developed in the cells (when carried out on
the large scale) is drawn away by fans and conducted in closed pipes to
the place where it is used.

Many researches have been published as to the character of the skin
affection well known under the name of _chlorine rash_ (chlorakne).
Some maintain that it is not due to chlorine at all, but is an eczema
set up by tar. Others maintain that it is due to a combined action of
chlorine and tar. Support to this view is given by the observation that
cases of chlorine rash, formerly of constant occurrence in a factory
for electrolytic manufacture of chlorine, disappeared entirely on
substitution of magnetite at the anode for carbon.[1] The conclusion
seems justified that the constituents of the carbon or of the surrounding
material set up the condition.

Chlorine rash has been observed in an alkali works where chlorine was
not produced electrolytically, and under conditions which suggested that
compounds of tar and chlorine were the cause. In this factory for the
production of salt cake by the Hargreaves’ process cakes of rock salt
were prepared and, for the purpose of drying, conveyed on an endless
metal band through a stove. To prevent formation of crusts the band
was tarred. The salt blocks are decomposed in the usual way by sulphur
dioxide, steam, and oxygen of the air, and the hydrochloric acid vapour
led through Deacon towers in which the decomposition of the hydrochloric
acid into chlorine and water is effected by metal salts in the manner
characteristic of the Deacon process. These salts are introduced in small
earthenware trays which periodically have to be removed and renewed;
the persons engaged in doing this were those affected. The explanation
was probably that the tar sticking to the salt blocks distilled in the
saltcake furnaces and formed a compound with the chlorine which condensed
on the earthenware trays. When contact with these trays was recognised as
the cause, the danger was met by observance of the greatest cleanliness
in opening and emptying the Deacon towers.

Leymann[2] is certain that the rash is due to chlorinated products which
emanate from the tar used in the construction of the cells. And the
affection has been found to be much more prevalent when the contents of
the cells are emptied while the contents are still hot than when they are
first allowed to get cold.

Lehmann[3] has approached the subject on the experimental side, and is of
opinion that probably chlorinated tar derivatives (chlorinated phenols)
are the cause of the trouble. Both he and Roth think that the affection
is due not to external irritation of the skin, but to absorption of the
poisonous substances into the system and their elimination by way of the
glands of the skin.

In the section on manganese poisoning detailed reference is made to the
form of illness recently described in persons employed in drying the
regenerated Weldon mud.

Mercurial poisoning is possible when mercury is used in the production of
chlorine electrolytically.

In the manufacture of chlorates and hypochlorite, bleaching fluids, &c.,
injury to health from chlorine is possible in the same way as has been
described above.


OTHER CHLORINE COMPOUNDS. BROMINE, IODINE, AND FLUORINE

Chlorine is used for the production of a number of organic chlorine
compounds, and in the manufacture of bromine and iodine, processes
which give rise to the possibility of injury to health and poisoning by
chlorine; further, several of the substances so prepared are themselves
corrosive or irritating or otherwise poisonous. Nevertheless, severe
poisoning and injurious effects can be almost entirely avoided by
adoption of suitable precautions. In the factory to which Leymann’s
figures refer, where daily several thousand kilos of chlorine and organic
chlorine compounds are prepared, a relatively very favourable state of
health of the persons employed was noted. At all events the preparation
of chlorine by the electrolytic process takes place in closed vessels
admirably adapted to avoid any escape of chlorine gas except as the
result of breakage of the apparatus or pipes. When this happens, however,
the pipes conducting the gas can be immediately disconnected and the
chlorine led into other apparatus or into the bleaching powder factory.

As such complete precautionary arrangements are not everywhere to be
found, we describe briefly the most important of the industries in
question and the poisoning recognised in them.

_Chlorides of phosphorus._—By the action of dry chlorine on an excess
of heated amorphous phosphorus, trichloride is formed (PCl₃), a
liquid having a sharp smell and causing lachrymation, which fumes
in the air, and in presence of water decomposes into phosphorous
acid and hydrochloric acid. On heating with dry oxidising substances
it forms phosphorus oxychloride (see below), which is used for the
production of acid chlorides. By continuous treatment with chlorine
it becomes converted into phosphorus pentachloride (PCl₅), which also
is conveniently prepared by passing chlorine through a solution of
phosphorus in carbon bisulphide, the solution being kept cold; it is
crystalline, smells strongly, and attacks the eyes and lungs. With excess
of water it decomposes into phosphoric acid and hydrochloric acid:
with slight addition of water it forms phosphorus oxychloride (POCl₃).
On the large scale this is prepared by reduction of phosphate of lime
in the presence of chlorine with carbon or carbonic oxide. Phosphorus
oxychloride, a colourless liquid, fumes in the air and is decomposed by
water into phosphoric acid and hydrochloric acid.

In the preparation of chlorides of phosphorus, apart from the danger of
chlorine gas and hydrochloric acid, the poisonous effect of phosphorus
and its compounds (see Phosphorus) and even of carbon disulphide (as
the solvent of phosphorus) and of carbonic oxide (in the preparation of
phosphorus oxychloride) have to be taken into account.

Further, the halogen compounds of phosphorus exert irritant action on
the eyes and lungs similar to chloride of sulphur as a result of their
splitting up on the moist mucous membranes into hydrochloric acid and an
oxyacid of phosphorus.[4]

Unless, therefore, special measures are taken, the persons employed
in the manufacture of phosphorus chlorides suffer markedly from the
injurious emanations given off.[5]

Leymann[6] mentions one case of poisoning by phosphorus chloride as
having occurred in the factory described by him. By a defect in the
outlet arrangement phosphorus oxychloride flowed into a workroom.
Symptoms of poisoning (sensation of suffocation, difficulty of breathing,
lachrymation, &c.) at once attacked the occupants; before much gas had
escaped, the workers rushed out. Nevertheless, they suffered from severe
illness of the respiratory organs (bronchial catarrh and inflammation of
the lungs, with frothy, blood-stained expectoration, &c.).[7]

_Chlorides of sulphur._—Monochloride of sulphur (S₂Cl₂) is made by
passing dried, washed chlorine gas into molten heated sulphur. The oily,
brown, fuming liquid thus made is distilled over into a cooled condenser
and by redistillation purified from the sulphur carried over with it.
Sulphur monochloride can take up much sulphur, and when saturated is used
in the vulcanisation of indiarubber, and, further, is used to convert
linseed and beetroot oil into a rubber substitute. Monochloride of
sulphur is decomposed by water into sulphur dioxide, hydrochloric acid,
and sulphur. By further action of chlorine on the monochloride, sulphur
dichloride (SCl₂) and the tetrachloride (SCl₄) are formed.

In its preparation and use (see also Indiarubber Manufacture) the
injurious action of chlorine, of hydrochloric acid, and of sulphur
dioxide comes into play.

The monochloride has very irritating effects. Leymann cites an industrial
case of poisoning by it. In the German factory inspectors’ reports for
1897 a fatal case is recorded. The shirt of a worker became saturated
with the material owing to the bursting of a bottle. First aid was
rendered by pouring water over him, thereby increasing the symptoms,
which proved fatal the next day. Thus the decomposition brought about by
water already referred to aggravated the symptoms.

_Zinc chloride_ (ZnCl₂) is formed by heating zinc in presence of
chlorine. It is obtained pure by dissolving pure zinc in hydrochloric
acid and treating this solution with chlorine. Zinc chloride is
obtained on the large scale by dissolving furnace calamine (zinc
oxide) in hydrochloric acid. Zinc chloride is corrosive. It is used
for impregnating wood and in weighting goods. Besides possible injury
to health from chlorine and hydrogen chloride, risk of arseniuretted
hydrogen poisoning is present in the manufacture if the raw materials
contain arsenic. Eulenburg considers that in soldering oppressive zinc
chloride fumes may come off if the metal to be soldered is first wiped
with hydrochloric acid and then treated with the soldering iron.

_Rock salt._—Mention may be made that even to salt in combination with
other chlorides (calcium chloride, magnesium chloride, &c.) injurious
effects are ascribed. Ulcers and perforation of the septum of the nose in
salt-grinders and packers who were working in a room charged with salt
dust are described.[8] These effects are similar to those produced by the
bichromates.


Organic Chlorine Compounds

_Carbon oxychloride_ (COCl₂, carbonyl dichloride, phosgene) is produced
by direct combination of chlorine and carbonic oxide in presence of
animal charcoal. Phosgene is itself a very poisonous gas which, in
addition to the poisonous qualities of carbonic oxide (which have to be
borne in mind in view of the method of manufacture), acts as an irritant
of the mucous membranes. Commercially it is in solution in toluene and
xylene, from which the gas is readily driven off by heating. It is used
in the production of various colours, such as crystal violet, Victoria
blue, auramine, &c.

A fatal case of phosgene gas poisoning in the report of the Union of
Chemical Industry for 1905 deserves mention. The phosgene was kept in a
liquefied state in iron bottles provided with a valve under 2·3 atm.
pressure. The valve of one of these bottles leaked, allowing large escape
into the workroom. Two workers tried but failed to secure the valve. The
cylinder was therefore removed by a worker, by order of the manager,
and placed in a cooling mixture, as phosgene boils at 8° C. The man in
question wore a helmet into which air was pumped from the compressed air
supply in the factory. As the helmet became obscured through moisture
after five minutes the worker took it off. A foreman next put on the
cleaned mask, and kept the cylinder surrounded with ice and salt for
three-quarters of an hour, thus stopping the escape of gas. Meanwhile,
the first worker had again entered the room, wearing a cloth soaked in
dilute alcohol before his mouth, in order to take a sack of salt to the
foreman. An hour and a half later he complained of being very ill, became
worse during the night, and died the following morning. Although the
deceased may have been extremely susceptible, the case affords sufficient
proof of the dangerous nature of the gas, which in presence of moisture
had decomposed into carbonic acid and hydrochloric acid; the latter had
acutely attacked the mucous membrane of the respiratory passages and set
up fatal bronchitis. Further, it was found that the leaden plugs of the
valves had been eroded by the phosgene.

Three further cases of industrial phosgene poisoning have been
reported,[9] one a severe case in which there was bronchitis with
blood-stained expectoration, great dyspnœa, and weakness of the heart’s
action. The affected person was successfully treated with ether and
oxygen inhalations. Phosgene may act either as the whole molecule, or is
inhaled to such degree that the carbonic oxide element plays a part.

In another case of industrial phosgene poisoning the symptoms were those
of severe irritation of the bronchial mucous membrane and difficulty of
breathing.[10] The case recovered, although sensitiveness of the air
passages lasted a long time.

_Carbon chlorine compounds_ (_aliphatic series_).—_Methyl chloride_
(CH₃Cl) or chlormethane is prepared from methyl alcohol and hydrochloric
acid (with chloride of zinc) or methyl alcohol, salt, and sulphuric acid.
It is prepared in France on a large scale from beetroot _vinasse_ by dry
distillation of the evaporation residue. The distillate, which contains
methyl alcohol, trimethylamine, and other methylated amines, is heated
with hydrochloric acid; the methyl chloride so obtained is purified,
dried and compressed. It is used in the preparation of pure chloroform,
in the coal-tar dye industry, and in surgery (as a local anæsthetic). In
the preparation of methyl chloride there is risk from methyl alcohol,
trimethylamine, &c. Methyl chloride itself is injurious to health.

_Methylene chloride_ (CH₂Cl₂, dichlormethane) is prepared in a similar
way. It is very poisonous.

_Carbon tetrachloride_ (CCl₄, tetrachlormethane) is technically
important. It is prepared by passing chlorine gas into carbon bisulphide
with antimony or aluminium chloride. Carbon tetrachloride is a liquid
suitable for the extraction of fat or grease (as in chemical cleaning),
and has the advantage of being non-inflammable. Carbon tetrachloride, so
far as its poisonous qualities are concerned, is to be preferred to other
extractives (see Carbon Bisulphide, Benzine, &c.); for the rest it causes
unconsciousness similar to chloroform.

When manufactured industrially, in addition to the poisonous effect of
chlorine, the poisonous carbon bisulphide has also to be borne in mind.

_Ethyl chloride_ (C₂H₅Cl) is made in a way analogous to methyl chloride
by the action of hydrochloric acid on ethyl alcohol and chloride of zinc.
It is used in medicine as a narcotic.

_Monochloracetic acid._—In the preparation of monochloracetic acid
hydrochloric acid is developed in large quantity. From it and anthranilic
acid artificial indigo is prepared (according to Heuman) by means of
caustic potash.

_Chloral_ (CCl₃CHO, trichloracetaldehyde) is produced by chlorinating
alcohol. Chloral is used in the preparation of pure chloroform and (by
addition of water) of chloral hydrate (trichloracetaldehyde hydrate), the
well-known soporific.

_Chloroform_ (CHCl₃, trichlormethane).—Some methods for the preparation
of chloroform have been already mentioned (Chloral, Methyl Chloride).
Technically it is prepared by distillation of alcohol or acetone with
bleaching powder. The workers employed are said to be affected by the
stupefying vapours. Further, there is the risk of chlorine gas from use
of chloride of lime.

_Chloride of nitrogen_ (NCl₃) is an oily, volatile, very explosive,
strongly smelling substance, which irritates the eyes and nose violently
and is in every respect dangerous; it is obtained from the action of
chlorine or hypochlorous acid on sal-ammoniac. The poisonous nature of
these substances may come into play. Risk of formation of chloride of
nitrogen can arise in the production of gunpowder from nitre containing
chlorine.

_Cyanogen chloride_ (CNCl).—Cyanogen chloride is made from hydrocyanic
acid or cyanide of mercury and chlorine. Cyanogen chloride itself is an
extremely poisonous and irritating gas, and all the substances from which
it is made are also poisonous. According to Albrecht cyanogen chloride
can arise in the preparation of red prussiate of potash (by passage of
chlorine gas into a solution of the yellow prussiate) if the solution is
treated with chlorine in excess; the workers may thus be exposed to great
danger.

_Chlorobenzene._—In his paper referred to Leymann cites three cases of
poisoning by chlorobenzene, one by dinitrochlorobenzene, and, further,
three cases of burning by chlorobenzene and one by benzoyl chloride
(C₆H₅COCl). The last named is made by treating benzaldehyde with
chlorine, and irritates severely the mucous membranes, while decomposing
into hydrochloric acid and benzoic acid.[11] Benzal chloride (C₆H₅CHCl₂),
benzo trichloride (C₆H₅CCl₃), and benzyl chloride (C₆H₅CH₂Cl) are
obtained by action of chlorine on boiling toluene. The vapours of these
volatile products irritate the respiratory passages. In the manufacture
there is risk from the effect of chlorine gas and toluene vapour (see
Benzene, Toluene).

Leymann[12] describes in detail six cases of poisoning in persons
employed in a chlorobenzene industry, of which two were due to
nitrochlorobenzene. Symptoms of poisoning—headache, cyanosis, fainting,
&c.—were noted in a person working for three weeks with chlorobenzene.[13]

In Lehmann’s opinion chlorine rash, the well-recognised skin affection
of chlorine workers, may be due to contact with substances of the
chlorbenzol group.[14]

_Iodine and iodine compounds._—Formerly iodine was obtained almost
exclusively from the liquor formed by lixiviation of the ash of seaweed
(kelp, &c.); now the principal sources are the mother liquors from
Chili saltpetre and other salt industries. From the concentrated liquor
the iodine is set free by means of chlorine or oxidising substances
and purified by distillation and sublimation. Iodine is used for the
preparation of photographic and pharmaceutical preparations, especially
iodoform (tri-iodomethane, CHI₃), which is made by acting with iodine and
caustic potash on alcohol, aldehyde, acetone, &c.

Apart from possible injurious action of chlorine when used in the
preparation of iodine, workers are exposed to the possibility of chronic
iodine poisoning. According to Ascher[15] irritation effects, nervous
symptoms, and gastric ulceration occur in iodine manufacture and use.
He considers that bromide of iodine used in photography produces these
irritating effects most markedly. Layet and also Chevallier in older
literature have made the same observations.

The Swiss Factory Inspectors’ Report for 1890-1 describes two acute
cases of iodine poisoning in a factory where organic iodine compounds
were made; one terminated fatally (severe cerebral symptoms, giddiness,
diplopia, and collapse).

_Bromine and bromine compounds._—Bromine is obtained (as in the case of
iodine) principally from the mother liquors of salt works (especially
Stassfurt saline deposits) by the action of chlorine or nascent oxygen
on the bromides of the alkalis and alkaline earths in the liquors. They
are chiefly used in photography (silver bromide), in medicine (potassium
bromide, &c.), and in the coal-tar dye industry.

The danger of bromine poisoning (especially of the chronic form) is
present in its manufacture and use, but there is no positive evidence of
the appearance of the bromine rash among the workers. On the other hand,
instances are recorded of poisoning by methyl bromide, and the injurious
effect of bromide of iodine has been referred to.

_Methyl iodide and methyl bromide._—Methyl iodide (CH₃I), a volatile
fluid, is obtained by distillation of wood spirit with amorphous
phosphorus and iodine; it is used in the production of methylated
tar colours and for the production of various methylene compounds.
Grandhomme describes, in the paper already referred to, six cases, some
very severe, of poisoning by the vapour of methyl iodide among workers
engaged in the preparation of antipyrin, which is obtained by the action
of aceto-acetic ether on phenyl hydrazine, treatment of the pyrazolone
so obtained with methyl iodide, and decomposition of the product with
caustic soda. A case of methyl iodide poisoning is described in a factory
operative, who showed symptoms similar to those described for methyl
bromide except that the psychical disturbance was more marked.[16]

Three cases of methyl bromide (CH₃Br) poisoning are described in persons
preparing the compound.[17] One of these terminated fatally. There
is some doubt as to whether these cases were really methyl bromide
poisoning. But later cases of methyl bromide poisoning are known, and
hence the dangerous nature of this chemical compound is undoubted. Thus
the Report of the Union of Chemical Industry for 1904 gives the following
instance: Two workers who had to deal with an ethereal solution of methyl
bromide became ill with symptoms of alcoholic intoxication. One suffered
for a long time from nervous excitability, attacks of giddiness, and
drowsiness. Other cases of poisoning from methyl bromide vapour are
recorded with severe nervous symptoms and even collapse.

_Fluorine compounds._—_Hydrogen fluoride_ (HFl) commercially is a watery
solution, which is prepared by decomposition of powdered fluorspar by
sulphuric acid in cast-iron vessels with lead hoods. The escaping fumes
are collected in leaden condensers surrounded with water; sometimes to
get a very pure product it is redistilled in platinum vessels.

Hydrogen fluoride is used in the preparation of the fluorides of
antimony, of which antimony fluoride ammonium sulphate (SbFl₃(NH₄)₂SO₄)
has wide use in dyeing as a substitute for tartar emetic. It is produced
by dissolving oxide of antimony in hydrofluoric acid with addition of
ammonium sulphate and subsequent concentration and crystallisation.
Hydrofluoric acid is used for etching glass (see also Glass Industry).

In brewing, an unpurified silico-fluoric acid mixed with silicic acid,
clay, oxide of iron, and oxide of zinc called Salufer is used as a
disinfectant and preservative.

_Hydrofluoric acid and silicofluoric acid_ (H₂SiFl₆) arise further
in the superphosphate industry by the action of sulphuric acid on the
phosphorites whereby silicofluoric acid is obtained as a bye-product
(see also Manufacture of Artificial Manure). Hydrofluoric acid and its
derivatives both in their manufacture and use and in the superphosphate
industry affect the health of the workers.

If hydrogen fluoride or its compounds escape into the atmosphere they
attack the respiratory passages and set up inflammation of the eyes;
further, workers handling the watery solutions are prone to skin
affections (ulceration).

The following are examples of the effects produced.[18] A worker in an
art establishment upset a bottle of hydrofluoric acid and wetted the
inner side of a finger of the right hand. Although he immediately washed
his hands, a painful inflammation with formation of blisters similar to a
burn of the second degree came on within a few hours. The blister became
infected and suppurated.

A man and his wife wished to obliterate the printing on the top of
porcelain beer bottle stoppers with hydrofluoric acid. The man took a
cloth, moistened a corner of it, and then rubbed the writing off. After a
short time he noticed a slight burning sensation and stopped. His wife,
who wore an old kid glove in doing the work, suffered from the same
symptoms, the pain from which in the night became unbearable, and in
spite of medical treatment gangrene of the finger-tips ensued. Healing
took place with suppuration and loss of the finger-nails.

Injury of the respiratory passages by hydrofluoric acid has often been
reported. In one factory for its manufacture the hydrofluoric acid vapour
was so great that all the windows to a height of 8 metres were etched
dull.

Several cases of poisoning by hydrofluoric acid were noted by me when
examining the certificates of the Sick Insurance Society of Bohemia. In
1906 there were four due to inhalation of vapour of hydrofluoric acid in
a hydrofluoric acid factory, with symptoms of corrosive action on the
mucous membrane of the respiratory tract. In 1907 there was a severe case
in the etching of glass.[19]


NITRIC ACID.

MANUFACTURE AND USES.—_Nitric acid_ (HNO₃) is obtained by distillation
when Chili saltpetre (sodium nitrate) is decomposed by sulphuric acid in
cast-iron retorts according to the equation:

    NaNO₃ + H₂SO₄ = NaHSO₄ + HNO₃.

Condensation takes place in fireclay Woulff bottles connected to a
coke tower in the same way as has been described in the manufacture of
hydrochloric acid.

[Illustration: FIG. 9.—Preparation of Nitric Acid (_after Ost_)]

Lunge-Rohrmann plate towers are also used instead of the coke tower.
Earthenware fans—as is the case with acid gases generally—serve to
aspirate the nitrous fumes.

To free the nitric acid of the accompanying lower oxides of nitrogen
(as well as chlorine, compounds of chlorine and other impurities) air
is blown into the hot acid. The mixture of sodium sulphate and sodium
bisulphate remaining in the retorts is either converted into sulphate by
addition of salt or used in the manufacture of glass.

The nitric acid obtained is used either as such or mixed with sulphuric
acid or with hydrochloric acid.

Pure nitric acid cannot at ordinary atmospheric pressure be distilled
unaltered, becomes coloured on distillation, and turns red when exposed
to light. It is extremely dangerous to handle, as it sets light to straw,
for example, if long in contact with it. It must be packed, therefore, in
kieselguhr earth, and when in glass carboys forwarded only in trains for
transport of inflammable material.

Red, _fuming nitric acid_, a crude nitric acid, contains much nitrous
and nitric oxides. It is produced if in the distillation process less
sulphuric acid and a higher temperature are employed or (by reduction) if
starch meal is added.

The successful production of nitric acid from the air must be referred
to. It is effected by electric discharges in special furnaces from which
the air charged with nitrous gas is led into towers where the nitric
oxide is further oxidised (to tetroxide), and finally, by contact with
water, converted into nitric acid.

Nitric acid is used in the manufacture of phosphoric acid, arsenious
acid, and sulphuric acid, nitro-glycerin and nitrocellulose, smokeless
powder, &c. (see the section on Explosives), in the preparation of
nitrobenzenes, picric acid, and other nitro-compounds (see Tar Products,
&c.). The diluted acid serves for the solution and etching of metals,
also for the preparation of nitrates, such as the nitrates of mercury,
silver, &c.

EFFECTS ON HEALTH.—Leymann considers that the average number of cases and
duration of sickness among persons employed in the nitric acid industry
are generally on the increase; the increase relates almost entirely to
burns which can hardly be avoided with so strongly corrosive an acid. The
number of burns amounts almost to 12 per cent. according to Leymann’s
figures (i.e. on an average 12 burns per 100 workers), while among the
packers, day labourers, &c., in the same industry the proportion is only
1 per cent. Affections of the respiratory tract are fairly frequent (11·8
per cent. as compared with 8·8 per cent. of other workers), which is no
doubt to be ascribed to the corrosive action of nitrous fumes on the
mucous membranes. Escape of acid fumes can occur in the manufacture of
nitric acid though leaky retorts, pipes, &c., and injurious acid fumes
may be developed in the workrooms from the bisulphate when withdrawn from
the retorts, which is especially the case when excess of sulphuric acid
is used. The poisonous nature of these fumes is very great, as is shown
by cases in which severe poisoning has been reported from merely carrying
a vessel containing fuming nitric acid.[1]

Frequent accidents occur through the corrosive action of the acid or
from breathing the acid fumes—apart from the dangers mentioned in the
manufacture—in filling, packing, and despatching the acid—especially
if appropriate vessels are not used and they break. Of such accidents
several are reported.

Further, reports of severe poisoning from the use of nitric acid are
numerous. Inhalation of nitrous fumes (nitrous and nitric oxides, &c.)
does not immediately cause severe symptoms or death; severe symptoms tend
to come on some hours later, as the examples cited below show.

Occurrence of such poisoning has already been referred to when describing
the sulphuric acid industry. In the superphosphate industry also
poisoning has occurred by accidental development of nitric oxide fumes on
sodium nitrate mixing with very acid superphosphate.

Not unfrequently poisoning arises in pickling metals (belt making,
pickling brass; cf. the chapter on Treatment of Metals). Poisoning by
nitrous fumes has frequently been reported from the action of nitric acid
on organic substances whereby the lower oxides of nitrogen—nitrous and
nitric oxides—are given off. Such action of nitric acid or of a mixture
of nitric and sulphuric acid on organic substances is used for nitrating
purposes (see Nitroglycerin; Explosives; Nitrobenzol).

Through want of care, therefore, poisoning can arise in these industries.
Again, this danger is present on accidental contact of escaping acid with
organic substances (wood, paper, leather, &c.), as shown especially by
fires thus created.[2]

Thus, in a cellar were five large iron vessels containing a mixture of
sulphuric and nitric acids. One of the vessels was found one morning to
be leaking. The manager directed that smoke helmets should be fetched,
intending to pump out the acid, and two plumbers went into the cellar
to fix the pump, staying there about twenty-five minutes. They used
cotton waste and handkerchiefs as respirators, but did not put on the
smoke helmets. One plumber suffered only from cough, but the other died
the same evening with symptoms of great dyspnœa. At the autopsy severe
inflammation and swelling of the mucous membrane of the palate, pharynx
and air passages, and congestion of the lungs were found.

Two further fatal cases in the nitrating room are described by Holtzmann.
One of the two complained only a few hours after entering the room of
pains in the chest and giddiness. He died two days later. The other died
the day after entering the factory, where he had only worked for three
hours. In both cases intense swelling and inflammation of the mucous
membrane was found.

Holtzmann mentions cases of poisoning by nitrous fumes in the heating of
an artificial manure consisting of a mixture of saltpetre, brown coal
containing sulphur, and wool waste. Fatalities have been reported in
workers who had tried to mop up the spilt nitric acid with shavings.[3]
We quote the following other instances[4]:

(1) Fatal poisoning of a fireman who had rescued several persons from a
room filled with nitrous fumes the result of a fire occasioned by the
upsetting of a carboy. The rescued suffered from bronchial catarrh, the
rescuer dying from inflammation and congestion of the lungs twenty-nine
hours after the inhalation of the gas.

(2) At a fire in a chemical factory three officers and fifty-seven
firemen became affected from inhalation of nitrous fumes, of whom one
died.

(3) In Elberfeld on an open piece of ground fifty carboys were stored.
One burst and started a fire. As a strong wind was blowing the firemen
were little affected by the volumes of reddish fumes. Soon afterwards at
the same spot some fifty to sixty carboys were destroyed. Fifteen men
successfully extinguished the fire in a relatively still atmosphere in
less than half an hour. At first hardly any symptoms of discomfort were
felt. Three hours later all were seized with violent suffocative attacks,
which in one case proved fatal and in the rest entailed nine to ten days’
illness from affection of the respiratory organs.

The Report of the Union for Chemical Industry for 1908 describes a
similar accident in a nitro-cellulose factory.

Of those engaged in extinguishing the fire twenty-two were affected, and
in spite of medical treatment and use of the oxygen apparatus three died.

From the same source we quote the following examples:

In a denitrating installation (see Nitro-glycerin; Explosives) a man was
engaged in blowing, by means of compressed air, weak nitric acid from a
stoneware vessel sunk in the ground into a washing tower. As the whole
system was already under high pressure the vessel suddenly exploded, and
in doing so smashed a wooden vat containing similar acid, which spilt on
the ground with sudden development of tetroxide vapours. The man inhaled
much gas, but except for pains in the chest felt no serious symptoms at
the time and continued to work the following day. Death occurred the next
evening from severe dyspnœa.

A somewhat similar case occurred in the nitrating room of a dynamite
factory in connection with the cleaning of a waste acid egg; the vessel
had for several days been repeatedly washed out with water made alkaline
with unslaked lime. Two men then in turn got into the egg in order to
remove the lime and lead deposit, compressed air being continuously blown
in through the manhole. The foreman remained about a quarter of an hour
and finished the cleaning without feeling unwell. Difficulty of breathing
came on in the evening, and death ensued on the following day.

In another case a worker was engaged in washing nitroxylene when, through
a leak, a portion of the contents collected in a pit below. He then
climbed into the pit and scooped the nitroxylene which had escaped into
jars. This work took about three-quarters of an hour, and afterwards he
complained of difficulty of breathing and died thirty-six hours later.[5]

A worker again had to control a valve regulating the flow to two large
vessels serving to heat or cool the nitrated liquid. Both vessels were
provided with pressure gauges and open at the top. Through carelessness
one of the vessels ran over, and instead of leaving the room after
closing the valve, the man tried to get rid of the traces of his error,
remaining in the atmosphere charged with the fumes,[6] and was poisoned.


Nitric and Nitrous Salts and Compounds

When dissolving in nitric acid the substances necessary for making the
various nitrates, nitric and nitrous oxides escape. In certain cases
nitric and hydrochloric acids are used together to dissolve metals such
as platinum and gold and ferric oxides, when chlorine as well as nitrous
oxide escapes. Mention is necessary of the following:

_Barium nitrate_ (Ba(NO₃)₂) is prepared as a colourless crystalline
substance by acting on barium carbonate or barium sulphide with nitric
acid. Use is made of it in fireworks (green fire) and explosives. In
analogous way strontium nitrate (Sr(NO₃)₂) is made and used for red fire.

_Ammonium nitrate_ (NH₄NO₃), a colourless crystalline substance, is
obtained by neutralising nitric acid with ammonia or ammonium carbonate,
and is also made by dissolving iron or tin in nitric acid. It is used in
the manufacture of explosives.

_Lead nitrate_ (Pb(NO₃)₂), a colourless crystalline substance, is made by
dissolving lead oxide or carbonate in nitric acid. It is used in dyeing
and calico printing, in the preparation of chrome yellow and other lead
compounds, and mixed with lead peroxide (obtained by treatment of red
lead with nitric acid) in the manufacture of lucifer matches. Apart from
risk from nitrous fumes (common to all these salts) there is risk also of
chronic lead poisoning.

_Nitrate of iron_ (Fe(NO₃)₂), forming green crystals, is made by
dissolving sulphide of iron or iron in cold dilute nitric acid. The
so-called nitrate of iron commonly used in dyeing consists of basic
sulphate of iron (used largely in the black dyeing of silk).

_Copper nitrate_ (Cu(NO₃)₂), prepared in a similar way, is also used in
dyeing.

_Mercurous nitrate_ (Hg₂(NO₃)₂) is of great importance industrially, and
is produced by the action of cold dilute nitric acid on an excess of
mercury. It is used for ‘carotting’ rabbit skins in felt hat making, for
colouring horn, for etching, and for forming an amalgam with metals, in
making a black bronze on brass (art metal), in painting on porcelain, &c.

_Mercuric nitrate_ (Hg(NO₃)₂) is made by dissolving mercury in nitric
acid or by treating mercury with excess of warm nitric acid. Both the
mercurous and mercuric salts act as corrosives and are strongly poisonous
(see also Mercury and Hat Manufacture).

_Nitrate of silver_ (AgNO₃) is obtained by dissolving silver in nitric
acid and is used commercially as a caustic in the well-known crystalline
pencils (lunar caustic). Its absorption into the system leads to
accumulation of silver in the skin—the so-called argyria (see Silver).
Such cases of chronic poisoning are recorded by Lewin.[7] Argyria occurs
among photographers and especially in the silvering of glass pearls owing
to introduction of a silver nitrate solution into the string of pearls by
suction. In northern Bohemia, where the glass pearl industry is carried
on in the homes of the workers, I saw a typical case. The cases are now
rare, as air pumps are used instead of the mouth.

_Sodium nitrite_ (NaNO₂) is obtained by melting Chili saltpetre with
metallic lead in cast-iron vessels. The mass is lixiviated and the
crystals obtained on evaporation. The lead oxide produced is specially
suitable for making red lead. Cases of lead poisoning are frequent and
sometimes severe. Roth[8] mentions a factory where among 100 employed
there were 211 attacks in a year.

_Amyl nitrite_ (C₅H₁₁NO₂) is made by leading nitrous fumes into iso-amyl
alcohol and distilling amyl alcohol with potassium nitrite and sulphuric
acid. It is a yellowish fluid, the fumes of which when inhaled produce
throbbing of the bloodvessels in the head and rapid pulse.

For other nitric acid compounds see the following section on Explosives
and the section on Manufacture of Tar Products (Nitro-benzene, &c.).


Explosives

Numerous explosives are made with aid of nitric acid or a mixture of
nitric and sulphuric acids. Injury to health and poisoning—especially
through development of nitrous fumes—can be caused. Further, some
explosives are themselves industrial poisons, especially those giving off
volatile fumes or dust.

The most important are:

_Fulminate of mercury_ (HgC₂N₂O₂) is probably to be regarded as the
mercury salt of fulminic acid, an isomer of cyanic acid. It is used
to make caps for detonating gunpowder and explosives, and is made by
dissolving mercury in nitric acid and adding alcohol. The heavy white
crystals of mercury fulminate are filtered off and dried. Very injurious
fumes are produced in the reaction, containing ethyl acetate, acetic
acid, ethyl nitrate, nitrous acid, volatile hydrocyanic acid compounds,
hydrocyanic acid, ethyl cyanide, cyanic acid; death consequently can
immediately ensue on inhalation of large quantities. The fulminate is
itself poisonous, and risk is present in filtering, pressing, drying,
and granulating it. Further, in filling the caps in the huts numerous
cases of poisoning occur. Heinzerling thinks here that mercury fumes are
developed by tiny explosions in the pressing and filling. In a factory in
Nuremburg 40 per cent. of the women employed are said to have suffered
from mercurial poisoning. Several cases in a factory at Marseilles are
recorded by Neisser.[9] In addition to the risk from the salt there is
even more from nitrous fumes, which are produced in large quantity in the
fulminate department.

_Nitro-glycerin_ (C₃H₅(O—NO₂)₃, dynamite, explosive
gelatine).—Nitro-glycerin is made by action of a mixture of nitric and
sulphuric acids on anhydrous glycerin. The method of manufacture is as
follows (see fig. 10): glycerin is allowed to flow into the acid mixture
in leaden vessels; it is agitated by compressed air and care taken that
the temperature remains at about 22° C., as above 25° there may be risk.
The liquid is then run off and separates into two layers, the lighter
nitro-glycerin floating on the top of the acid. The process is watched
through glass windows. The nitro-glycerin thus separated is run off,
washed by agitation with compressed air, then neutralised (with soda
solution) and again washed and lastly filtered. The acid mixture which
was run off is carefully separated by standing, as any explosive oil
contained in it will rise up. The waste acid freed from nitro-glycerin is
recovered in special apparatus, being denitrified by hot air and steam
blown through it. The nitrous fumes are condensed to nitric acid. The
sulphuric acid is evaporated.

_Dynamite_ is made by mixing nitro-glycerin with infusorial earth
previously heated to redness and purified.

_Blasting gelatine_ is made by dissolving gun cotton (collodion wool,
nitro-cellulose) in nitro-glycerin. Both are pressed into cartridge shape.

Nitro-glycerin itself is a strong poison which can be absorbed both
through the skin and from the alimentary canal. Kobert describes a case
where the rubbing of a single drop into the skin caused symptoms lasting
for ten hours. Workmen engaged in washing out nitro-glycerin from the
kieselguhr earth, having in doing so their bare arms immersed in the
liquid, suffered. Although it be granted that nitro-glycerin workers
become to a large extent acclimatised, cases of poisoning constantly
occur in explosives factories referable to the effect of nitro-glycerin.

Persons mixing and sieving dynamite suffer from ulcers under the nails
and at the finger-tips which are difficult to heal. Further, where the
apparatus employed is not completely enclosed nitrous fumes escape and
become a source of danger. Formerly this danger was constantly present
in the nitrating house where nitration was effected in open vessels.
Now that this is usually done in closed nitrating apparatus with glass
covers the danger is mainly limited to the acid separating house, wash
house, and especially the room in which denitration of the waste acids is
effected.

[Illustration: FIG. 10.—Preparation of Nitro-glycerin. Nitrating Vessel
(_after Guttmann_)

A Glycerine reservoir; C Fume flue; D Acid supply pipe; E, G Compressed
air supply; H, J Cooling coil.]

A fatal case in a nitro-glycerin factory was reported in 1902 where,
through carelessness, a separator had overflowed. The workman who tried
to wash away the acid with water inhaled so much of the nitrous fumes
that he succumbed sixteen hours later.

Other cases of poisoning by nitrous fumes occurring in the denitrating
department are described in detail in the section on the use of nitric
acid.

One of these occurred to a man forcing dilute nitric acid from an
earthenware egg by means of compressed air into a washing tower. The egg
burst and broke an acid tank. The workman died on the following day.

A fatal case occurred in a dynamite factory in cleaning out a storage
tank for waste acid in spite of previous swilling and ventilation.

_Gun cotton_ (_pyroxyline_) and its use.—Pyroxyline is the collective
name for all products of the action of nitric acid on cellulose (cotton
wool and similar material); these products form nitric acid ester of
cellulose (nitro-cellulose).

Gun cotton is formed by the action of strong nitric acid on cellulose
(cotton wool). A mixture of sulphuric and nitric acids is allowed to act
on cotton wool (previously freed from grease, purified, and dried), with
subsequent pressing and centrifugalising. In the nitrating centrifugal
machine (in the Selvig-Lange method) both processes are effected at the
same time.

The interior of this apparatus is filled with nitric acid, cotton wool is
introduced, the acid fumes exhausted through earthenware pipes, and the
remainder of the acid removed by the centrifugal machine; the nitrated
material is then washed, teazed in teazing machines, again washed,
neutralised with calcium carbonate, again centrifugalised, and dried.
Since drying in drying stoves is a great source of danger of explosion,
dehydration is effected with alcohol, and the gun cotton intended for
the production of smokeless powder carried directly to the gelatinising
vessels (see Smokeless Powder).

Gun cotton, apart from its use for smokeless powder, is pressed in prisms
and used for charging torpedoes and sea mines.

_Collodion cotton_ is a partially nitrated cellulose. It is prepared
generally in the same way as gun cotton, except that it is treated with
a more dilute acid. It is soluble (in contradistinction to gun cotton)
in alcohol-ether, and the solution is known as collodion (as used in
surgery, photography, and to impregnate incandescent gas mantles). Mixed
with camphor and heated collodion forms celluloid.

In Chardonnet’s method for making artificial silk collodion is used by
forcing it through fine glass tubes and drawing and spinning it. The
alcohol-ether vapours are carried away by fans and the spun material is
de-nitrated by ammonium sulphide.

_Smokeless powder_ is a gun cotton powder—that is gun cotton the
explosive power of which is utilised by bringing it into a gelatinous
condition. This is effected by gelatinising the gun cotton with
alcohol-ether or acetone (sometimes with addition of camphor, resin,
&c.). A doughy, pasty mass results, which is then rolled, washed, dried,
and pressed into rods. Nobel’s nitroleum (artillery powder) consists half
of nitro-glycerin and half of collodion cotton. In the production of gun
cotton and collodion cotton the workers are affected and endangered by
nitric and nitrous fumes unless the nitrating apparatus is completely
airtight.

Erosion of the incisor teeth is general, but use of the new nitrating
apparatus, especially of the nitrating centrifugal machines already
described, has greatly diminished the evil. In making collodion,
celluloid and artificial silk, in addition to the risks referred to
in the production of gun cotton, the vapour from the solvents, ether,
alcohol, acetone, acetic-ether, and camphor, comes into consideration,
but there is no account of such poisoning in the literature of the
subject.

Other explosives which belong to the aromatic series are described in the
chapter on Tar Derivatives, especially picric acid.


PHOSPHORUS AND PHOSPHORUS MATCHES

The total production of _phosphorus_ is not large. Formerly it was
prepared from bone ash. Now it is made from phosphorite, which, as
in the super-phosphate industry, is decomposed by means of sulphuric
acid, soluble phosphate and calcium sulphate being formed; the latter
is removed, the solution evaporated, mixed with coal or coke powder,
distilled in clay retorts, and received in water.

Phosphorus is also obtained electro-chemically from a mixture of
tricalcium phosphate, carbon, and silicic acid, re-distilled for further
purification, and finally poured under water into stick form.

_Red phosphorus_ (amorphous phosphorus) is obtained by heating yellow
phosphorus in the absence of air and subsequently extracting with carbon
bisulphide.

_Phosphorus matches_ are made by first fixing the wooden splints in
frames and then dipping the ends either into paraffin or sulphur which
serve to carry the flame to the wood. Then follows dipping in the
phosphorus paste proper, for which suitable dipping machines are now
used. The phosphorus paste consists of yellow phosphorus, an oxidising
agent (red lead, lead nitrate, nitre, or manganese dioxide) and a binding
substance (dextrine, gum); finally the matches are dried and packed.

_Safety matches_ are made in the same way, except that there is no
phosphorus. The paste consists of potassium chlorate, sulphur, or
antimony sulphide, potassium bichromate, solution of gum or dextrine,
and different admixtures such as glass powder, &c. These matches are
saturated with paraffin or ammonium phosphate. To strike them a special
friction surface is required containing red phosphorus, antimony
sulphide, and dextrine. In the act of striking the heat generated
converts a trace of the red phosphorus into the yellow variety which
takes fire.

Danger to health arises from the poisonous gases evolved in the
decomposition of the calcined bones by sulphuric acid. When phosphorus is
made from phosphorite the same dangers to health are present as in the
production of super-phosphate artificial manure, which is characterised
by the generation of hydrofluoric and fluosilicic acids. In the
distillation of phosphorus phosphoretted hydrogen and phosphorus fumes
may escape and prove dangerous.

Industrial poisoning from the use of white phosphorus in the manufacture
of matches has greater interest than its occurrence in the production
of phosphorus itself. Already in 1845 chronic phosphorus poisoning
(phosphorus necrosis) had been observed by Lorinser, and carefully
described by Bibra and Geist in 1847. In the early years of its use
phosphorus necrosis must have been fairly frequent in lucifer match
factories, and not infrequently have led to death. This necessitated
preventive measures in various States (see Part III); cases became fewer,
but did not disappear altogether.

Especially dangerous is the preparation of the paste, dipping, and
manipulations connected with drying and filling the matches into boxes.
According to the reports of the Austrian factory inspectors there are
about 4500 lucifer match workers in that country, among whom seventy-four
cases of necrosis are known to have occurred between the years 1900 and
1908 inclusive.

Teleky[1] considers these figures much too small, and from inquiries
undertaken himself ascertained that 156 cases occurred in Austria
between 1896 and 1906, while factory inspectors’ reports dealt with only
seventy-five. He was of opinion that his own figures were not complete,
and thinks that in the ten years 1896 to 1905 there must have been from
350 to 400 cases of phosphorus necrosis in the whole of Austria. Despite
strict regulations, modern equipment of the factories, introduction of
improved machinery, and limitation of the white phosphorus match industry
to large factories, it has not been possible to banish the risk, and the
same is true of Bohemia, where there is always a succession of cases.
Valuable statistics of phosphorus necrosis in Hungary are available.[2]
In 1908 there were sixteen factories employing 1882 workers of whom
30 per cent. were young—children even were employed. The industry is
carried on in primitive fashion without hygienic arrangements anywhere.
It is strange that, notwithstanding these bad conditions, among a large
number of the workers examined only fourteen active cases were found, in
addition to two commencing, and fifteen cured—altogether thirty-one cases
(excluding fifty-five cases in which there was some other pathological
change in the mouth). Altogether ninety-three cases since 1900 were
traced in Hungary, and in view of the unsatisfactory situation preventive
measures, short of prohibition of the use of white phosphorus, would be
useless.

In England among 4000 lucifer match workers there were thirteen cases
in the years 1900 to 1907 inclusive. Diminution in the number was due
to improved methods of manufacture and periodical dental examination
prescribed under Special Rules.

Phosphorus necrosis is not the only sign of industrial phosphorus
poisoning, as the condition of fragilitas ossium is recognised.[3]
From what has been said it is evident that preventive measures against
phosphorus poisoning, although they diminish the number, are not able to
get rid of phosphorus necrosis, and so civilised States have gradually
been driven to prohibit the use of white phosphorus (for the history of
this see Part III).

Use of chrome salts (especially potassium bichromate) in the preparation
of the paste causes risk of poisoning in premises where ‘Swedish’
matches are made. Attention has been called to the frequency of chrome
ulceration.[4] The paste used consists of 3-6 per cent. chrome salt, so
that each match head contains about ½ mg. Wodtke found among eighty-four
workers early perforation of the septum in thirteen. Severe eczema also
has been noted.

It is even alleged that red phosphorus is not entirely free from danger.
Such cachexia as has been noted may be referable to the absorption of
potassium chlorate.


Other Uses of Phosphorus and Compounds of Phosphorus

Isolated cases of phosphorus poisoning have been observed in the
manufacture of phosphor-bronze. This consists of 90 parts copper, 9 parts
tin, and 0·5 to 0·75 phosphorus.

_Sulphides of phosphorus_ (P₂S₅, P₄S₃, P₂S₃) are made by melting together
red phosphorus and sulphur. They make a satisfactory substitute for the
poisonous yellow phosphorus and are considered non-poisonous, but the
fact remains that they give off annoying sulphuretted hydrogen gas.

_Phosphoretted hydrogen gas_ (PH₃) rarely gives rise to industrial
poisoning. It may come off in small amounts in the preparation of
acetylene and in the preparation of, and manipulations with, white
phosphorus. It is stated that in acetylene made of American calcium
carbide 0·04 per cent. of phosphoretted hydrogen is present, and in
acetylene from Swedish calcium carbide 0·02 per cent.; Lunge and
Cederkreutz found an acetylene containing 0·06 per cent. These amounts
might cause poisoning if the gas were diffused in confined spaces.
Poisoning, in part attributable to phosphoretted hydrogen gas, is brought
about through ferro-silicon (see under Ferro-silicon).


Superphosphate and Artificial Manure

_Superphosphate_, an artificial manure, is prepared from various
raw materials having a high proportion of insoluble basic calcium
phosphate (tricalcium phosphate), which by treatment with sulphuric
acid are converted into the soluble acid calcium phosphate (monocalcium
phosphate) and calcium sulphate. Mineral substances such as phosphorites,
coprolites, guano, bone ash, &c., serve as the starting-point. Chamber
acid, or sometimes the waste acid from the preparation of nitro-benzene
or purification of petroleum, are used in the conversion. The raw
materials are ground in closed-in apparatus, under negative pressure,
and mixed with the sulphuric acid in wooden lead-lined boxes or walled
receptacles. The product is then stored until the completion of the
reaction in ‘dens,’ dried, and pulverised in disintegrators.

In the manufacture of bone meal extraction of the fat from the bones with
benzine precedes treatment with acid.

A further source of artificial manure is _basic slag_—the slag left in
the manufacture of steel by the Gilchrist-Thomas method—which contains
10-25 per cent. of readily soluble phosphoric acid. It requires,
therefore, only to be ground into a very fine powder to serve as a
suitable manure.

Owing to the considerable heat generated by the action of the sulphuric
acid when mixed with the pulverised raw materials (especially in the
conversion of the phosphorites) hydrofluoric and silicofluoric acid
vapours are evolved in appreciable amount, and also carbonic and
hydrochloric acid vapours, sulphur dioxide, and sulphuretted hydrogen
gas. These gases—notably such as contain fluorine—if not effectually
dealt with by air-tight apparatus and exhaust ventilation—may lead to
serious annoyance and injury to the persons employed. Further, there is
risk of erosion of the skin from contact with the acid, &c.

A case is described of pustular eczema on the scrotum of a worker engaged
in drying sodium silicofluoride, due probably to conveyance of irritating
matter by the hands. After the precaution of wearing gloves was adopted
the affection disappeared.

A marked case of poisoning by nitrous fumes even is recorded in the
manufacture of artificial manure from mixing Chili saltpetre with a very
acid superphosphate.

Injurious fumes can be given off in the rooms where bones are stored and,
in the absence of efficient ventilation, carbonic acid gas can accumulate
to an amount that may be dangerous.

The fine dust produced in the grinding of _basic slag_ has, if inhaled, a
markedly corrosive action on the respiratory mucous membrane attributed
by some to the high proportion (about 50 per cent.) in it of quicklime.
As a matter of fact numerous small ulcers are found on the mucous
membranes of basic slag grinders and ulceration of the lung tissue has
been observed. The opinion is expressed that this is due to corrosive
action of the dust itself, and not merely to the sharp, jagged edged
particles of dust inhaled. And in support of this view is cited the
frequency with which epidemics of pneumonia have been noted among
persons employed in basic slag works. Thus in Nantes thirteen cases of
severe pneumonia followed one another in quick succession. And similar
association has been noted in Middlesbrough, where the action of the
basic slag dust was believed to injure the lung tissue and therefore to
provide a favourable soil for the development of the pneumonia bacillus.
Statistics collected by the Imperial Health Office showed that in the
three years 1892, 1893, and 1894, 91·1 per cent., 108·9 per cent., and
91·3 per cent. respectively of the workers became ill, the proportion
of respiratory diseases being 56·4 per cent., 54·4 per cent., and 54·3
per cent. respectively. A case of severe inflammation of the lungs is
described in a labourer scattering basic slag in a high wind which drove
some of it back in his face.

Lewin has described a case in which a worker scattering a mixture of
basic slag and ammonium superphosphate suffered from an eczematous
ulceration which, on being scratched by the patient, became infected and
led to death from general blood poisoning. Lewin regarded the fatal issue
as the sequela of the scattering of the manure.

Inflammation of the conjunctiva and of the eyelids has been recorded.


CHROMIUM COMPOUNDS AND THEIR USES

Chrome ironstone, lime, and soda are ground and intimately mixed. They
are next roasted in reverberatory furnaces, neutral _sodium chromate_
being formed. This is lixiviated and converted into sodium bichromate
(Na₂Cr₂O₇) by treatment with sulphuric acid. Concentration by evaporation
follows; the concentrated liquor is crystallised in cast-iron tanks. The
crystals are centrifugalised, dried, and packed. _Potassium bichromate_
may be made in the same way, or, as is usually the case, out of sodium
bichromate and potassium chloride.

The bichromates are used in the preparation and oxidation of chrome
colours, but their principal use is in dyeing and calico printing,
bleaching palm oil, purifying wood spirit and brandy, in the preparation
of ‘Swedish’ matches, in the manufacture of glass, in photography, in
dyeing, in tanning, and in oxidation of anthracene to anthraquinone.


Lead Chromate and Chrome Colours

_Chrome yellow_ is neutral lead chromate (PbCrO₄). It is obtained by
precipitating a solution of potassium bichromate with lead acetate or
lead nitrate, or by digesting the bichromate solution with lead sulphate,
and is used as a paint and in calico and cloth printing. With Paris or
Berlin blue it forms a _chrome green_. _Chrome orange_, i.e. basic lead
chromate (PbCrO₄Pb(OH)₂) is made by adding milk of lime to lead chromate
and boiling.

_Chromium_ and _chromic acid salts_ are widely used in dyeing and
printing, both as mordants and oxidising agents and as dyes (chrome
yellow, chrome orange). In mordanting wool with potassium chromate the
wool is boiled in a potassium chromate solution to which acids such as
sulphuric, lactic, oxalic, or acetic are added.

In dyeing with chrome yellow, for instance, the following is the process.
Cotton wool is saturated with nitrate or acetate of lead and dried,
passed through lime water, ammonia, or sodium sulphate, and soaked in a
warm solution of potassium bichromate. The yellow is converted into the
orange colour by subsequent passage through milk of lime.

_Chrome tanning._—This method of producing chrome leather, first patented
in America, is carried out by either the single or two bath process.

In the two bath process the material is first soaked in a saturated
solution of bichromate and then treated with an acid solution of
thiosulphate (sodium hyposulphite) so as to reduce completely the chromic
acid. The process is completed even with the hardest skins in from two to
three days.

In the single bath method basic chrome salts are used in highly
concentrated form. The skins are passed from dilute into strong
solutions. In this process also tanning is quickly effected.

EFFECTS ON HEALTH.—Among the persons employed in the bichromate factory
of which Leymann has furnished detailed particulars, the number of sick
days was greater than that among other workers.

Further, _erosion of the skin_ (_chrome holes_) is characteristic of
the manufacture of bichromates. These are sluggish ulcers taking a long
time to heal. This is the main cause of the increased general morbidity
that has been observed. The well-known perforation of the septum of the
nose without, however, causing ulterior effects, was observed by Leymann
in all the workers in the factory. This coincides with the opinion of
others who have found the occurrence of chrome holes, and especially
perforation of the septum, as an extraordinarily frequent occurrence.
Many such observations are recorded,[1] and also in workers manufacturing
‘Swedish’ matches. Thus of 237 bichromate workers, ulcers were present
in 107 and perforation in 87. According to Lewin, who has paid special
attention to the poisonous nature of chromium compounds, they can act in
two ways: first, on the skin and mucous membrane, where the dust alights,
on the alimentary tract by swallowing, and on the pharynx by inhalation.
Secondly, by absorption into the blood, kidney disease may result.

The opinion that chromium, in addition to local, can have constitutional
effect is supported by other authorities. Leymann describes a case
of severe industrial chrome poisoning accompanied by nephritis in a
worker who had inhaled and swallowed much chromate dust in cleaning
out a vessel. Regulations for the manufacture of bichromates (see Part
III) have no doubt improved the condition, but reports still show that
perforation of the septum generally takes place.

It must be borne in mind that practically all chromium compounds are not
alike poisonous. Chrome ironstone is non-poisonous, and the potassium
and sodium salts are by far the most poisonous, while the neutral
chromate salts and chromic oxide are only slightly so. Pander found that
bichromates were 100 times as poisonous as the soluble chromium oxide
compounds, and Kunkel is of opinion that poisonous effect shown by the
oxides is attributable to traces of oxidation into chromic acid.

Lewin, on the other hand, declares in a cautionary notice for chrome
workers generally that all chromium compounds are poisonous, and
therefore all the dyes made from them.[2]

In the manufacture of bichromates, chance of injury to health arises
partly from the dust, and partly from the steam, generated in pouring
water over the molten mass. The steam carries particles of chromium
compounds with it into the air. In evaporating the chromate solutions,
preparation of the bichromate, breaking the crystals, drying and packing,
the workers come into contact with the substance and the liquors. Chrome
ulceration is, therefore, most frequently found among those employed in
the crystal room and less among the furnace hands.

From 3·30 to 6·30 mg. of bichromate dust have been found in 1 c.m. of air
at breathing level in the room where chromate was crushed, and 1·57 mg.
where it was packed. Further, presence of chromium in the steam escaping
from the hot chrome liquors has been proved.[3]

Poisoning from use of chrome colours is partly attributable to lead, as,
for example, in making yellow coloured tape measures, yellow stamps, and
from the use of coloured thread. Gazaneuve[4] found 10 per cent. of lead
chromate in such thread, in wool 18 per cent., and in the dust of rooms
where such yarn was worked up 44 per cent.

Use of chrome colours and mordants is accompanied by illness which
certainly is referable to the poisonous nature of the chrome. In France
use of chromic and phosphoric acid in etching zinc plates has caused
severe ulceration.

Bichromate poisoning has been described among photographers in Edinburgh
in the process of carbon printing, in which a bichromate developer is
used.[5]

There is much evidence as to occurrence of skin eruptions and
development of pustular eczema of the hands and forearms of workers in
chrome tanneries.[6] In a large leather factory where 300 workers were
constantly employed in chrome tanning nineteen cases of chrome ulceration
were noted within a year. Injury to health was noted in a chrome tannery
in the district of Treves, where the two bath process was used, from
steam developed in dissolving the chromate in hot water.

Finally, I have found several records in 1907 and 1908 of perforation of
the septum in Bohemian glass workers.


MANGANESE COMPOUNDS

The raw material of the manganese industry is _hausmannite_ (manganese
dioxide, MnO₂). This is subjected to a crushing process, sorted, sieved,
finely ground, washed, and dried. The pure finely ground manganese
dioxide is much used in the chemical industry, especially in the
recovery of chlorine in the Weldon process and in the production of
_potassium permanganate_, which is obtained by melting manganese dioxide
with caustic soda and potassium chlorate or nitre, lixiviation and
introduction of carbonic acid, or better by treatment with ozone.

Manganese is also used in the production of colours: the natural and
artificial umbers contain it; in glass works it is used to decolourise
glass, and also in the production of coloured glass and glazes; in the
manufacture of stove tiles, and in the production of driers for the
varnish and oil industry. Manganese and compounds of manganese are
dangerous when absorbed into the system as dust.

Already in 1837 nervous disorders had been described in workmen who
ground manganese dioxide.[1] The malady was forgotten, until Jaksch[2]
in Prague in 1901 demonstrated several such cases in persons employed
in a large chemical factory in Bohemia, from the drying of Weldon mud.
In the same year three similar cases were also described in Hamburg.[3]
In 1902 Jaksch observed a fresh case of poisoning, and in the factory
in question described a condition of manganophobia among the workers,
obviously hysterical, in which symptoms of real manganese poisoning were
simulated. In all some twenty cases are known. Jaksch is of opinion that
it is manganese dust rich in manganese protoxide that is alone dangerous,
since, if the mud has been previously treated with hydrochloric acid, by
which the lower oxides are removed, no illness can be found. The most
dangerous compounds are MnO and Mn₃O₄.


PETROLEUM

OCCURRENCE AND USES.—Crude petroleum flows spontaneously from wells in
consequence of high internal pressure of gas or is pumped up. In America
and Russia also it is conveyed hundreds of miles in conduits to the ports
to be led into tank steamers.

The crude oil is a dark-coloured liquid which, in the case of
Pennsylvanian mineral oil, consists mainly of a mixture of hydrocarbons
of the paraffin series, or, in Baku oil, of those of the naphtha series.
There are in addition sulphur compounds, olefines, pyridin, &c. The
crude oil is unsuitable for illuminating purposes and is subjected to a
distillation process. It is split up into three fractions by a single
distillation, namely, (_a_) benzines (boiling-point 150° C.), (_b_)
lighting oil (boiling-point 150°-300° C.); at a temperature of 300° C.
the distillation is stopped so that (_c_) the residuum boiling above 300°
C. remains. Distillation is effected (in America) in large stills, in
which periodically benzine and lighting oil up to 300° C. is distilled
and the residuum run off. In Baku continuously working batteries of
so-called cylindrical boilers are used, into which the crude oil
streams. In the first set of boilers, the temperature in which rises to
150° C., the benzine is distilled off, and in the succeeding ones, heated
to 300° C., the illuminating petroleum oils (kerosine), the residuum
flowing continually away.

The _mineral oil residues_ are used as fuel. Heating by this means,
tried first only in Russia, is spreading, especially for the heating of
boilers, in which case the liquid fuel is blown in generally as a spray.
The combustion if rightly planned is economical and almost smokeless.

The American oil residuum, rich in paraffin, is distilled, the distillate
is cooled and separated by pressure into solid paraffin and liquid oil.
The latter and the Russian mineral oil residues which are free from
paraffin are widely used as lubricants. In the production of lubricants
the residues are distilled at low temperature (in vacuo or by aid of
superheated steam) and separated into various qualities by fractional
cooling, are then purified with sulphuric acid, and finally washed with
caustic soda solution.

In the preparation of vaseline the residum is not distilled, but purified
only with fuming sulphuric acid and decolourised with animal charcoal.

The _illuminating oil_ is next subjected to a purifying process
(refining); it is first treated with sulphuric acid and well agitated
by means of compressed air. The acid laden with the impurities is drawn
off below, and the oil freed from acid by washing first with caustic
soda and subsequently with water. It is then bleached in the sun. For
specially fine and high flash point petroleum the oil undergoes a further
distillation and purification with acid.

The fractions of crude petroleum with low boiling-point (under 150° C.)
are known commercially as raw _benzine_ or _petrol naphtha_. It is used
for cleaning, in extraction of fats and oils, and for benzine motors.

Frequently raw benzine is subjected to a purifying process and to
fractional distillation. Purification is carried out by means of
sulphuric acid and soda liquor and subsequent separation into three
fractions and a residue which remains in the retort—(_a_) _petroleum
ether_ (called gasoline, canadol, and rhigoline), which comes over
between 40° and 70° C., and serves for carburetting water gas and other
similar gases, as a solvent for resin, oil, rubber, &c.; (_b_) _purified
benzine_ (70°-120° C.) is used as motor spirit and in chemical cleaning;
(_c_) _ligroine_ (120°-135° C.), used for illuminating purposes; and
(_d_) the _residual oil_ (above 135° C.) serves for cleaning machinery
and, especially, as a solvent for lubricating oil, and instead of
turpentine in the production of lacquers, varnishes, and oil colours.

In _chemical cleaning_ works benzine is used in closed-in washing
apparatus, after which the clothes are centrifugalised and dried. In
view of the risk of fire in these manipulations, originating mainly from
frictional electricity, various substances are recommended to be added
to the benzine, of which the best known is that recommended by Richter,
consisting of a watery solution of oleate of sodium or magnesium.

EFFECTS ON HEALTH.—Industrial poisoning in the petroleum industry is
attributable to the gases given off from crude petroleum or its products
and to inhalation of naphtha dust. Poisoning occurs principally in
the recovery of petroleum and naphtha from the wells, in storage and
transport (in badly ventilated tanks on board ship, and in entering
petroleum tanks), in the refinery in cleaning out petroleum stills and
mixing vessels, and in emptying out the residues. Further cases occur
occasionally from use of benzine in chemical cleaning.

In addition to poisoning the injurious effect of petroleum and its
constituents on the skin must be borne in mind. Opinion is unanimous
that this injurious action of mineral oil is limited to the petroleum
fractions with high boiling-point and especially petroleum residues.

Statistics officially collected in Prussia show the general health of
petroleum workers to be favourable. These statistics related to 1380
persons, of whom forty-three were suffering from symptoms attributable
to their occupation. Of these forty-three, nine only were cases of
poisoning, the remainder being all cases of petroleum acne.

The conditions also in French refineries from statistics collected in
the years 1890-1903 seem satisfactory. Eighteen cases of petroleum acne
were reported, eleven of which occurred at the paraffin presses, five in
cleaning out the still residues, and two were persons filling vessels.

The conditions are clearly less favourable in the Russian petroleum
industry.[1]

The workers at the naphtha wells suffer from acute and chronic affections
of the respiratory organs. Those suffer most who cover the wells with
cast iron plates to enable the flow of naphtha to be regulated and led
into the reservoirs. In doing this they inhale naphtha spray.

Lewin[2] describes cases of severe poisoning with fatal issue among
American workers employed in petroleum tanks. One man who wished to
examine an outlet pipe showed symptoms after only two minutes. Weinberger
describes severe poisoning of two workers engaged in cleaning out a
vessel containing petroleum residue.

Interesting particulars are given of the effect of petroleum emanations
on the health of the men employed in the petroleum mines of Carpathia,
among whom respiratory affections were rarely found, but poisoning
symptoms involving unconsciousness and cerebral symptoms frequently.
These experiences undoubtedly point to differing physiological effects of
different kinds of naphtha.

This is supported by the view expressed by Sharp in America that
different kinds of American petroleum have different effects on the
health of the workers, which can be easily credited from the different
chemical composition of crude naphthas. Thus in Western Virginia, where a
natural heavy oil is obtained, asphyxia from the gas is unknown, although
transient attacks of headache and giddiness may occur, whereas in Ohio,
where light oils are obtained, suffocative attacks are not infrequent.
And it is definitely stated that some naphtha products irritate the
respiratory passages, while others affect the central nervous system.[3]

The authors mentioned refer to occurrence of cases of poisoning in the
refining of naphtha from inhalation of the vapour of the light oils
benzine and gasoline. Fatal cases have been recorded in badly ventilated
workrooms in which the products of distillation are collected. Workers
constantly employed in these rooms develop chronic poisoning, which is
reported also in the case of women employed with benzine. Intoxication is
frequently observed, it is stated, among the workmen employed in cleaning
out the railway tank waggons in which the mineral oils and petroleum are
carried.

Foulerton[4] describes severe poisoning in a workman who had climbed into
a petroleum reservoir, and two similar cases from entering naphtha tanks
are given in the Report of the Chief Inspector of Factories for 1908. Two
fatal cases are reported by the Union of Chemical Industry in Germany
in 1905 in connection with naphtha stills. Such accidents are hardly
possible, except when, through insufficient disconnection of the still
from the further system of pipes, irrespirable distillation gases pass
backwards into the opened still where persons are working. Ordinary cocks
and valves, therefore, do not afford sufficient security. Thus, several
workers engaged in repairing a still were rendered unconscious by gases
drawn in from a neighbouring still, and were only brought round after
oxygen inhalation.

Gowers describes a case of chronic poisoning following on frequent
inhalation of gases given off from a petroleum motor, the symptoms
being slurring speech, difficulty of swallowing, and weakness of the
orbicularis and facial muscles. Gowers believed this to be petroleum
gas poisoning (from incomplete combustion), especially as the symptoms
disappeared on giving up the work, only to return on resuming it again.[5]

Girls employed in glove cleaning and rubber factories are described as
having been poisoned by benzine.[6] Poisoning of chauffeurs is described
by several writers.[7]

Recent literature[8] tends to show marked increase in the number of
cases of poisoning from greater demand for benzine as a motive power for
vehicles. Such cases have been observed in automobile factories, and are
attributable to the hydrocarbons of low boiling-point which are present
as impurities in benzine.

A worker in a paraffin factory had entered an open benzine still to
scrape the walls free of crusts containing benzine. He was found
unconscious and died some hours later. It appeared that he had been in
the still several hours, having probably been overcome to such an extent
by the fumes as to be unable to effect his escape.

Attempt to wipe up benzine spilt in the storage cellar of a large
chemical cleaning works resulted in poisoning.

A night worker in a bone extracting works having turned on the steam,
instead of watching the process fell asleep on a bench. In consequence
the apparatus became so hot that the solder of a stop valve melted,
allowing fumes to escape. The man was found dead in the morning. In a
carpet cleaning establishment three workers lost consciousness and were
found senseless on the floor. They recovered on inhalation of oxygen.

One further case reported from the instances of benzine poisoning
collected recently[9] is worth quoting. A worker in a chemical factory
was put to clean a still capable of distilling 2500 litres of benzine.
It contained remains of a previous filling. As soon as he had entered
the narrow opening he became affected and fell into the benzine; he
was carried unconscious to the hospital, his symptoms being vomiting,
spastic contraction of the extremities, cyanosis, weak pulse, and loss of
reflexes, which disappeared an hour and a half later.

The occurrence of skin affections in the naphtha industry has been noted
by several observers, especially among those employed on the unpurified
mineral oils. Eruptions on the skin from pressing out the paraffin and
papillomata (warty growths) in workers cleaning out the stills are
referred to by many writers,[10] Ogston in particular.

Recent literature refers to the occurrence of petroleum eczema in a
firebrick and cement factory. The workers affected had to remove the
bricks from moulds on to which petroleum oil dropped. An eczematous
condition was produced on the inner surface of the hands, necessitating
abstention from work. The pustular eczema in those employed only a short
time in pressing paraffin in the refineries of naphtha factories is
referred to as a frequent occurrence. Practically all the workers in
three refineries in the district of Czernowitz were affected. The view
that it is due to insufficient care in washing is supported by the report
of the factory inspector in Rouen, that with greater attention in this
matter on the part of the workers marked diminution in its occurrence
followed.


SULPHUR

RECOVERY AND USE.—Sulphur, which is found principally in Sicily (also in
Spain, America, and Japan), is obtained by melting. In Sicily this is
carried out in primitive fashion by piling the rock in heaps, covering
them with turf, and setting fire to them. About a third of the sulphur
burns and escapes as sulphur dioxide, while the remainder is melted and
collects in a hole in the ground.

The crude sulphur thus wastefully produced is purified by distillation in
cast-iron retorts directly fired. It comes on the market as stick or roll
sulphur or as flowers of sulphur.

Further sources for recovery of sulphur are the Leblanc soda residues
(see Soda Production), from which the sulphur is recovered by the
Chance-Claus process, and the gas purifying material (containing up to 40
per cent.), from which the sulphur can be recovered by carbon bisulphide
(see Illuminating Gas Industry).

The health conditions of the Sicilian sulphur workers are very
unsatisfactory, due, however, less to the injurious effect of the
escaping gases (noxious alike to the surrounding vegetation) than to the
wretched social conditions, over exertion, and under feeding of these
workers.

Of importance is the risk to health from sulphuretted hydrogen gas,
from sulphur dioxide in the recovery of sulphur from the soda residues,
and from carbon bisulphide in the extraction of sulphur from the gas
purifying material.


SULPHURETTED HYDROGEN GAS

Sulphuretted hydrogen gas is used in the chemical industry especially
for the precipitation of copper in the nickel and cobalt industry, in
de-arsenicating acid (see Hydrochloric and Sulphuric Acids), to reduce
chrome salts in the leather industry, &c. In addition it arises as a
product of decomposition in various industries, such as the Leblanc soda
process, in the preparation of chloride of antimony, in the decomposition
of barium sulphide (by exposure to moist air), in the treatment of gas
liquors, and in the preparation of carbon bisulphide: it is present
in blast furnace gas, is generated in mines (especially in deep seams
containing pyrites), arises in tar distillation, from use of gas lime
in tanning, and in the preparation and use of sodium sulphide: large
quantities of the gas are generated in the putrefactive processes
connected with organic sulphur-containing matter such as glue making,
bone stores, storage of green hides, in the decomposition of waste water
in sugar manufacture and brewing, in the retting of flax, and especially
in sewers and middens.

Both _acute_ and _chronic_ poisoning are described.

The following case is reported by the Union of Chemical Industry in 1907:
Three plumbers who were employed on the night shift in a chemical factory
and had gone to sleep in a workroom were found in a dying condition two
hours later. In the factory barium sulphide solution in a series of large
saturating vessels was being converted into barium carbonate by forcing
in carbonic acid gas; the sulphuretted hydrogen gas evolved was collected
in a gasometer, burnt, and utilised for manufacture of sulphuric acid. In
the saturating vessels were test cocks, the smell from which enabled the
workers to know whether all the sulphuretted hydrogen gas had been driven
out. If this was so the contents of the retort were driven by means of
carbonic acid gas into a subsidiary vessel, and the vessel again filled
with barium sulphide liquor. From these intermediate vessels the baryta
was pumped into filter presses, the last remains of sulphuretted hydrogen
gas being carried away by a fan into a ventilating shaft. The subsidiary
vessel and ventilating shaft were situated in front of the windows of
the repairing shop. On the night in question a worker had thoughtlessly
driven the contents out of one saturating vessel before the sulphuretted
hydrogen gas had been completely removed, and the driving belt of the fan
was broken. Consequently, the sulphuretted hydrogen gas escaping from
the subsidiary vessel entered through the windows of the workshop and
collected over the floor where the victims of the unusual combination of
circumstances slept.

In another chemical works two workers suffered from severe poisoning
in the barium chloride department. The plant consisted of a closed vat
which, in addition to the openings for admitting the barium sulphide
liquor and sulphuric acid, had a duct with steam injector connected
with the chimney for taking away the sulphuretted hydrogen gas. Owing
to a breakdown the plant was at a standstill, as a result of which the
ventilating duct became blocked by ice. When the plant was set in motion
again the sulphuretted hydrogen gas escaped through the sulphuric acid
opening. One of the workers affected remained for two days unconscious.[1]

The report of the Union of Chemical Industry for 1905 cites a case
where an agitating vessel, in which, by action of acid on caustic
liquor, sulphuretted hydrogen gas was given off and drawn away by a fan,
had to be stopped to repair one of the paddles. The flow of acid and
liquor was stopped, and the cover half removed. The deposit which had
been precipitated had to be got rid of next in order to liberate the
agitator. The upper portion of the vessel was washed out with water,
and since no further evolution of sulphuretted hydrogen was possible
from any manufacturing process, the work of removing the deposit was
proceeded with. After several bucketfuls had been emptied the man inside
became unconscious and died. The casualty was no doubt due to small
nests of free caustic and acid which the spading brought into contact
and subsequent developement of sulphuretted hydrogen afresh. A case
is reported of sulphuretted hydrogen poisoning in a man attending to
the drains in a factory tanning leather by a quick process. Here, when
sulphurous acid acts on sodium sulphide, sulphuretted hydrogen is given
off. In cleaning out a trap close to the discharge outlet of a tannery
two persons were rendered unconscious, and the presence of sulphuretted
hydrogen was shown by the blackening of the white lead paint on a house
opposite and by the odour.[2]

In the preparation of ammonium salts Eulenberg[3] cites several cases
where the workers fell as though struck down, although the processes were
carried on in the open air. They quickly recovered when removed from the
spot.

Oliver cites the case where, in excavating soil for a dock, four men
succumbed in six weeks; the water contained 12 vols. per cent. of
sulphuretted hydrogen.

Not unfrequently acute poisoning symptoms result to sewer men. Probably
sulphuretted hydrogen gas is not wholly responsible for them, nor for
the chronic symptoms complained of by such workers (inflammation of the
conjunctiva, bronchial catarrh, pallor, depression).

In the distillation processes connected with the paraffin industry
fatalities have been reported.


CARBON BISULPHIDE

MANUFACTURE.—Carbon bisulphide is prepared by passing sulphur vapour over
pure coal brought to a red heat in cast-iron retorts into which pieces of
sulphur are introduced. The crude carbon bisulphide requires purification
from sulphur, sulphuretted hydrogen, and volatile organic sulphur
compounds by washing with lime water and subsequent distillation.

Use is made of it principally in the extraction of fat and oil from bones
and oleaginous seeds (cocoanut, olives, &c.), for vulcanising, and as a
solvent of rubber. It is used also to extract sulphur from gas purifying
material and for the preparation of various chemical substances (ammonium
sulphocyanide, &c.), as well as for the destruction of pests (phylloxera
and rats).

Fat and oil are extracted from seeds, bones, &c., by carbon bisulphide,
benzine, or ether, and, to avoid evaporation, the vessels are as airtight
as possible and arranged, as a rule, for continuous working.

_Vulcanisation_ is the rendering of rubber permanently elastic by its
combination with sulphur. It is effected by means of chloride of sulphur,
sulphide of barium, calcium, or antimony, and other sulphur-containing
compounds, heat and pressure, or by a cold method consisting in the
dipping of the formed objects in a mixture of carbon bisulphide and
chloride of sulphur. The process of manufacture is briefly as follows:
The raw material is first softened and washed by hot water and kneading
in rolls. The washed and dried rubber is then mixed on callender
rolls with various ingredients, such as zinc white, chalk, white
lead, litharge, cinnabar, graphite, rubber substitutes (prepared by
boiling vegetable oils, to which sulphur has been added, with chloride
of sulphur). In vulcanising by aid of heat the necessary sulphur or
sulphur compound is added. Vulcanisation with sulphur alone is only
possible with aid of steam and mechanical pressure in various kinds of
apparatus according to the nature of the article produced. In the cold
vulcanisation process the previously shaped articles are dipped for a few
seconds or minutes in the mixture of carbon bisulphide and chloride of
sulphur and subsequently dried in warm air as quickly as possible.

In view of the poisonous nature of carbon bisulphide, benzine is much
used now. In the cold method use of chloride of sulphur in benzine can
replace it altogether.

Instead of benzine other solvents are available—chlorine substitution
products of methane (dichlormethane, carbon tetrachloride). In other
processes _rubber solvents_ are largely used, for instance, acetone, oil
of turpentine, petroleum benzine, ether, and benzene. Rubber solutions
are used for waterproofing cloth and other materials.

Similar to the preparation and use of rubber is that of guttapercha. But
vulcanisation is easier by the lead and zinc thiosulphate process than by
the methods used in the case of rubber.

EFFECTS ON HEALTH OF CS₂ AND OTHER DANGERS TO HEALTH IN THE RUBBER
INDUSTRY.—In the manufacture of carbon bisulphide little or no danger is
run either to health or from fire.

In the rubber trade the poisonous nature of _benzine_ and _chloride of
sulphur_ have to be borne in mind, and also the considerable risk of
_lead poisoning_ in mixing. Cases of plumbism, especially in earlier
years, are referred to.[1]

_Benzine_ poisoning plays only a secondary part in the rubber industry.
No severe cases are recorded, only slight cases following an inhalation
of fumes.

Cases of poisoning are recorded in a motor tyre factory in Upsala.[2]
Nine women were affected, of whom four died. Whether these cases were due
to benzene or petroleum benzine is not stated. It is remarkable that two
such very different substances as benzene and benzine should be so easily
confused.

But that in the rubber industry cases of benzene poisoning do actually
occur is proved by the following recent cases: Rubber dissolved in benzol
was being laid on a spreading machine in the usual way. Of three men
employed one was rendered unconscious and died.[3]

In a rubber recovery process a worker was rendered unconscious after
entering a benzol still, also two others who sought to rescue him. Only
one was saved.

Cases of aniline poisoning are reported where aniline is used for
extracting rubber.[4]

_Chloride of sulphur_, by reason of its properties and the readiness
with which it decomposes (see Chloride of Sulphur), causes annoyance to
rubber workers, but rarely poisoning.

Much importance attaches to _chronic carbon bisulphide poisoning_ in the
rubber industry. Many scientists have experimented as to its poisonous
nature (see especially on this Part II, p. 194).

Lehmann’s[5] experiments show that a proportion of 0·50-0·7 mg. of CS₂
per litre of air causes hardly any symptoms; 1·0-1·2 mg. slight effects
which become more marked on continued exposure; 1·5 mg. produces severe
symptoms. About 1·0 mg. per litre of air is the amount which may set up
chronic effects. In vulcanising rooms this limit may easily be exceeded
unless special preventive measures are adopted.

Laudenheimer[6] has made several analyses of the proportion of CS₂ in
workrooms. Thus 0·9-1·8 mg. per litre of air were found in a room where
pouches were vulcanised; 0·5-2·4 mg. were aspirated one-half metre
distant from the dipping vessels; and 0·18-0·27 mg. in the room for
making ‘baby comforters.’

In analyses made some years ago proportions of 2·9-5·6 mg. were obtained.

Although literature contains many references to CS₂ poisoning, too
much importance ought not to be attached to them now in view of the
arrangements in modern well-equipped vulcanising premises. Laudenheimer
has collected particulars of 31 cases of brain, and 19 of nervous,
diseases among 219 persons coming into contact with CS₂ between 1874
and 1908, all of whom had been medically attended. In the last ten
years, however, the psychical symptoms were seven times less than in the
preceding period. Between 1896 and 1898 the average proportion of brain
disease in the vulcanising department was 1·95 per cent., and of nervous
diseases 0·22 per cent., as compared with 0·92 per cent. and 0·03 per
cent. in the textile. Moreover, he maintains that practically all workers
who come at all into contact with CS₂ must be to some extent affected
injuriously by it.

Studies on the injurious nature of CS₂ date from the years 1851-60, when
the French writers Pazen, Duchenne, Beaugrand, Piorry, &c., came across
cases from the Parkes’ process (cold vulcanisation by means of CS₂ and
SCl₂). Delpech[7] published in 1860 and 1863 details of twenty-four
severe cases in rubber workers, some of which were fatal, and at the
same time described the pitiable conditions under which the work was
carried on.

In Germany Hermann, Hirt and Lewin, and Eulenberg dealt with the subject,
but their work is more theoretical in character; and in Laudenheimer’s
work referred to the histories of several cases are given in detail.

Mention should be made of the injury caused to the skin by the fluids
used in extraction of fat and in vulcanising—especially by benzine
and carbon bisulphide. Perrin considers the effect due partly to the
withdrawal of heat and partly to the solvent action on the natural
grease, producing an unpleasant feeling of dryness and contraction of the
skin.


ILLUMINATING GAS

Illuminating gas is obtained by the dry distillation of coal. The
products of distillation are subjected on the gasworks to several
purifying processes, such as condensation in coolers, moist and dry
purifying, from which valuable bye-products (such as tar, ammonia,
cyanogen compounds) are obtained. The purified gas is stored in gas
holders containing on an average 49 per cent. hydrogen, 34 per cent.
methane, 8 per cent. carbonic oxide, 1 per cent. carbon dioxide, 4
per cent. nitrogen, and about 4 per cent. of the heavy hydrocarbons
(ethylene, benzene vapour, acetylene, and their homologues) to which the
illuminating properties are almost exclusively due.

The most important stages in its preparation will be shortly described.
_Distillation_ is effected in cylindrical, usually horizontal, fireclay
retorts placed in a group or setting (fig. 11), which formerly were
heated by coke but in modern works always by gas. Charging with coal and
removal of the coke takes place about every four hours, often by means of
mechanical contrivances.

Iron pipes conduct the products of distillation to the _hydraulic main_.
This is a long covered channel extending the entire length of the stack
and receiving the gas and distillate from each retort. In it the greater
part of the tar and of the ammoniacal water condense and collect under
the water which is kept in the main to act as a seal to the ends of the
dip pipes, to prevent the gas from passing back into the retort when
the latter is opened. While the liquid flows from the hydraulic main
into cisterns, the gas passes into _coolers_ or _condensers_, tall iron
cylinders, in which, as the result of air and water cooling, further
portions of the tar and ammoniacal liquor are condensed. To free it still
more from particles of tar the gas passes through the _tar separator_.

[Illustration: FIG. 11.—Manufacture of Illuminating Gas. Horizontal
fireclay retorts placed in a setting and heated by gas(_after Ost_)]

The tar which remains behind flows through a tube to the cistern. From
the tar separator the gas goes through _scrubbers_ (fig. 12), where the
gas is washed free of ammonia and part of the sulphuretted hydrogen and
carbon dioxide with water. The scrubbers are tower-like vessels filled
with coke or charcoal through which the gas passes from below upwards,
encountering a spray of water. Several scrubbers in series are used, so
that the water constantly becomes richer in ammonia. Mechanical scrubbers
are much used, so-called standard washers; they are rotating, horizontal
cylinders having several chambers filled with staves of wood half dipping
in water. In them the same principle of making the gas meet an opposing
stream of water is employed, so that the last traces of ammonia are
removed from the gas.

The various purifying apparatus through which the gas has to pass cause
considerable resistance to its flow. Escape in various ways would occur
had the gas to overcome it by its own pressure, and too long contact of
the gas with the hot walls of the retorts would be detrimental. Hence an
exhauster is applied to the system which keeps the pressure to the right
proportion in the retorts and drives on the gas.

[Illustration: FIG. 12.—Washer or Scrubber]

After purification in the scrubbers _dry purification_ follows, having
for its object especially removal of compounds of sulphur and cyanogen
and carbon dioxide. To effect this several shallow receptacles are
used, each having a false bottom upon which the purifying material is
spread out. The boxes are so arranged that the gas first passes through
purifying material which is almost saturated and finally through fresh
material, so that the material becomes richer in sulphur and cyanogen
compounds. The _gas purifying material_ formerly used was slaked lime,
and it is still frequently used, but more generally bog iron ore or
artificially prepared mixtures are used consisting mostly of oxide of
iron. The saturated purifying material is regenerated by oxidation on
spreading it out in the air and turning it frequently. After having been
thus treated some ten times the mass contains 50 per cent. sulphur, and
13 to 14 per cent. ferrocyanide.

[Illustration: FIG. 13.—Manufacture of Illuminating Gas. Diagrammatic
view (_after Lueger_) A Retort setting and hydraulic main; B Condensers
and coolers; C Exhauster; D Well; E Water tank; F Tar extractor;
G Scrubber; H Purifier; I Station meter; K Gas holder; L Pressure
regulator.]

The _naphthalene_ in illuminating gas does not separate in the condenser,
and therefore is generally treated in special apparatus by washing the
gas with heavy coal tar.

The gas purified, as has been described, is measured by a meter and
stored in gasometers. These are bells made up of sheet iron which hang
down into walled receptacles filled with water to act as a water seal,
and are raised by the pressure of the gas which streams into them. The
gas passes to the network of mains by pressure of the weight of the
gasometer, after having passed through a pressure regulating apparatus.

As to recovery of bye-products in the illuminating gas industry, see the
sections on Ammonia, Cyanogen Compounds, Tar, Benzene, &c.

EFFECT ON HEALTH.—Opinions differ as to the effect on health which
employment in gas works exerts. This is true of old as well as of modern
literature.

Hirt[1] maintains that gas workers suffer no increase in illness because
of their employment. They reach, he says, a relatively high age and their
mortality he puts down at from 0·5 to 1 per cent. (my own observations
make me conclude that the average mortality among persons insured in sick
societies in Bohemia is 1 per cent., so that Hirt’s figure is not high).

Layet[2] agreed with Hirt, but was of opinion that gas workers suffered
from anæmia and gastro-intestinal symptoms attributable to inhalation of
injurious gases. The sudden symptoms of intoxication, ‘exhaustion and
sinking suddenly into a comatose condition,’ which he attributes to the
effect of hydrocarbons and sulphuretted hydrogen gas, may well have been
the symptoms of carbonic oxide poisoning.

Goldschmidt[3] in recent literature considers manufacture of illuminating
gas by no means dangerous or unhealthy, and speaks of no specific
maladies as having been observed by him. Nevertheless, he admits with
Layet that the men employed in the condensing and purifying processes are
constantly in an atmosphere contaminated by gas, and that the cleaning
and regeneration of the purifying mass is associated with inflammation of
the eyes, violent catarrh, and inflammation of the respiratory passages,
since, on contact of the purifying mass with the air, hydrocyanic acid
gas, sulphocyanic acid gas, and fumes containing carbolic, butyric, and
valerianic acids are generated.

Other writers[4] refer to the injurious effects from manipulating the
purifying material. In general, though, they accept the view, without
however producing any figures, that work in gas works is unattended with
serious injury to health and that poisonings, especially from carbonic
oxide, are rare. Such cases are described,[5] but the authors are not
quite at one as to the healthiness or otherwise of the industry. The one
opinion is based on study of the sick club reports for several years of
a large gas works employing some 2400 workers (probably Vienna).[6] The
average frequency of sickness (sickness percentage), excluding accidents,
was 48·7 per cent. The conclusion is drawn that the health conditions
of gas workers is favourable. It is pointed out, however, that diseases
of the respiratory and digestive organs (12·8 and 10·16 per cent. of
the persons employed) are relatively high, and that the mortality (1·56
per cent.) of gas-workers is higher than that of other workers. This
is attributed to the constant inhalation of air charged with injurious
gases. Work at the retorts, coke quenching, and attending to the
purifying plant are considered especially unhealthy.

The other figures relate to the Magdeburg gas works; they are higher
than those quoted. The morbidity of the gas workers was found to be 68·5
per cent., of which 18 per cent. was due to disease of the digestive
system, 20·5 per cent. to disease of the respiratory organs, and 1 per
cent. to poisoning. No details of the cases of poisoning are given.
Carbonic oxide poisoning is said to be not infrequent, the injurious
effect of cleaning the purifiers is referred to, and poisoning by
inhalation of ammonia is reported as possible.

Still, no very unfavourable opinion is drawn as to the nature of the
work. The sickness frequency in sick clubs is about 50 per cent., and
even in well-managed chemical works Leymann has shown it to be from 65 to
80 per cent. The recently published elaborate statistics of sickness and
mortality of the Leipzig local sickness clubs[7] contain the following
figures for gas workers: Among 3028 gas workers there were on an
average yearly 2046 cases of sickness, twenty deaths, and four cases of
poisoning. The total morbidity, therefore, was 67·57 per cent., mortality
0·66 per cent., and the morbidity from poisoning 0·13 per cent. Diseases
of the respiratory tract equalled 10·63 per cent., of the digestive
tract 10·87 per cent., of the muscular system 13·10 per cent., and from
rheumatism 11·10 per cent. These figures, therefore, are not abnormally
high and the poisoning is very low.

Still, industrial cases of poisoning in gas works are recorded. Of these
the most important will be mentioned. Six persons were employed in a
sub-station in introducing a new sliding shutter into a gas main, with
the object of deviating the gas for the filling of balloons. A regulating
valve broke, and the gas escaped from a pipe 40 cm. in diameter. Five
of the men were rendered unconscious, and resuscitation by means of
oxygen inhalation failed in one case. In repairing the damage done two
other cases occurred.[8] In emptying a purifier a worker was killed from
failure to shut off the valve.

Besides poisoning from illuminating gas, industrial poisoning in gas
works is described attributable, in part at least, to ammonia. Thus the
report of the factory inspectors of Prussia for 1904 narrates how a
worker became unconscious while superintending the ammonia water well,
fell in, and was drowned.

A further case is described in the report of the Union of Chemical
Industry for 1904. In the department for concentrating the gas liquor
the foreman and an assistant on the night shift were getting rid of the
residues from a washer by means of hot water. The cover had been removed,
but, contrary to instructions, the steam had not been shut off. Ammonia
fumes rushed out and rendered both unconscious, in which condition there
were found by the workmen coming in the morning.[9]

In the preparation of ammonium sulphate, probably in consequence of
too much steam pressure, gas liquor was driven into the sulphuric acid
receiver instead of ammonia gas. The receiver overflowed, and ammonia gas
escaped in such quantity as to render unconscious the foreman and two men
who went to his assistance.[10]

The use of illuminating gas in industrial premises can give rise to
poisoning. Thus the women employed in a scent factory, where so-called
quick gas heaters were used, suffered from general gas poisoning.[11]

In Great Britain in 1907 sixteen cases of carbonic oxide poisoning from
use of gas in industrial premises were reported.


COKE OVENS

Coke is obtained partly as a residue in the retorts after the production
of illuminating gas. Such _gas coke_ is unsuitable for metallurgical
purposes, as in the blast furnace. Far larger quantities of coal are
subjected to dry distillation for metallurgical purposes in coke ovens
than in gas works. Hence their erection close to blast furnaces. In the
older form of coke oven the bye-products were lost. Those generally used
now consist of closed chambers heated from the outside, and they can be
divided into coke ovens which do, and those which do not, recover the
bye-products. These are the same as those which have been considered
under manufacture of illuminating-gas—tar, ammonia, benzene and its
homologues, cyanogen, &c. In the coke ovens in which the bye-products are
not recovered the gases and tarry vapours escaping on coking pass into
the heating flues, where, brought into contact with the air blast, they
burn and help to heat the oven, while what is unused goes to the main
chimney stack.

[Illustration: FIG. 14.—Distillation Coke Oven (_after Lueger_)

A, A´ Coal to be coked; B, B´ Standpipes; C Hydraulic main; D Condensing
apparatus; E Purified gas: F, F´ Air inlets; G G,´ G´´ Combustion
chambers.]

In the modern _distillation ovens_ with recovery of the bye-products the
gases escaping from the coal are led (air being cut off as completely as
possible) through ascending pipes into the main collector, where they are
cooled, and the tarry ingredients as well as a part of the ammonia are
absorbed by water; subsequently the gases pass through washing apparatus
with a view to as complete a recovery of the ammonia and benzene as
possible. The purified gases are now again led to the ovens and burnt
with access of air in the combustion chambers between two ovens.
Generally these ovens are so constructed as to act as non-recovery ovens
also (especially in starting the process).

The coal is charged into the ovens through charge holes on the top
and brought to a level in the chambers either by hand or mechanically.
Removal of the coke block after completion of the coking operation is
done by a shield attached to a rack and pinion jack. Afterwards the coke
is quenched with water.

Recovery of the _bye-products_ of coke distillation ovens is similar to
the method described for illuminating gas, i.e. first by condensation
with aid of air or water cooling, then direct washing with water
(generally in scrubbers), whereby tar and ammonia water are recovered.
_Recovery of benzene_ and its homologues (see Benzene later) depends on
the fact that the coke oven gases freed from tar and ammonia are brought
into the closest possible contact with the so-called wash oils, i.e. coal
tar oils with high boiling-point (250-300° C.). For this purpose several
washing towers are employed. The waste oil enriched with benzene is
recovered in stills intermittently or continuously and used again.

EFFECTS ON HEALTH.—Injury to health from work at coke ovens is similar
to that in the manufacture of illuminating gas. There is the possibility
of carbonic oxide poisoning from escape of gas from leakage in the
apparatus. As further possible sources of danger ammonia, cyanogen and
sulpho-cyanogen compounds, and benzene have to be borne in mind.

In the distillation of the wash oil severe poisoning can arise, as in a
case described, where two men were fatally poisoned in distilling tar
with wash oil.[1]

The details of the case are not without interest. The poisoning occurred
in the lavatory. The gases had escaped from the drain through the
ventilating shaft next to the closet. The gases came from distillation of
the mixture of tar and wash oil, and were driven by means of air pumps
in such a way that normally the uncondensed gases made their way to the
chimney stack. On the day of the accident the pumps were out of use, and
the gases were driven by steam injectors into the drain. Analysis showed
the gases to contain much sulphuretted hydrogen. When this was absorbed,
a gas which could be condensed was obtained containing carbon bisulphide
and hydrocarbons of unknown composition (? benzene). Only traces of
cyanogen and sulpho-cyanogen compounds were present. Physiological
experiment showed that poisoning was attributable mainly to sulphuretted
hydrogen gas, but that after this was removed by absorption a further
poisonous gas remained.


Other Kinds of Power and Illuminating Gas

_Producer gas_ or _generator gas_.—Manufacture of producer gas consists
in dealing separately with the generation of the gas and the combustion
of the gases which arise. This is effected by admitting only so much air
(primary air supply) to the fuel as is necessary to cause the gases to
come off, and then admitting further air (secondary supply) at the point
where the combustion is to take place; this secondary supply and the gas
formed in the gas producer are heated in regenerators before combustion
by bringing the gases to be burnt into contact with _Siemens’s heaters_,
of which there are four. Two of these are always heated and serve to heat
the producer gas and secondary air supply.

[Illustration: FIG. 15.—Horizontal Regenerative Grate (_after Lueger_)]

A producer gas furnace, therefore, consists of a gas producer, a gas main
leading to the furnace hearth, the heater, and the chimney.

[Illustration: FIG. 16.—Step Regenerative Grate (_after Lueger_)]

The gas producer is a combustion chamber filled with coal in which
the coal in the upper layer is burnt. Generators may have horizontal
or sloping grate (see figs. 15 and 16). The _Siemens’s_ heaters or
regenerators are chambers built of, and filled loosely with, fireclay
bricks and arranged in couples. Should the gas producers become too hot,
instead of the chambers subdivided air heaters are used, whereby the hot
furnace gases are brought into contact with a system of thin-walled,
gastight fireclay pipes, to which they give up their heat, while the
secondary air supply for the furnace is led beside these pipes and so
becomes heated indirectly. Previous heating of the producer gas is here
not necessary; no valves are needed because the three streams of gas all
pass in the same direction.

[Illustration: FIG. 17A.—Siemens’s Regenerative Furnace

L Air; G Gas

FIG. 17B.—Siemens’s Regenerative Furnace]

Such air heating arrangements are used for heating the retorts in gas
works, for melting the ‘metal’ in glass works, and very generally in
other industries, as they offer many technical and hygienic advantages.
Generator gas from coke contains 34 per cent. carbonic oxide, 0·1 per
cent. hydrogen, 1·9 per cent. carbon dioxide, and 64 per cent. nitrogen.

_Blast furnace gas._—Blast furnace gas is formed under the same
conditions as have been described for generator gas; it contains more
carbon dioxide (about 10 per cent.). (Further details are given in the
section on Iron—Blast Furnaces.)

_Water gas._—Water gas is made by the passage of steam through
incandescent coal, according to the equation:

    C + H₂O = CO + 2H.

The iron gas producer, lined with firebrick, is filled with anthracite
or coke and heated by blowing hot air through it. This causes producer
gas to escape, after which steam is blown through, causing water gas to
escape—containing hydrogen and carbonic oxide to the extent of 45-50 per
cent., carbon dioxide and nitrogen 2-6 per cent., and a little methane.

The blowing of hot air and steam is done alternately, and both kinds of
gas are led away and collected separately, the water gas being previously
purified in scrubbers, condensers, and purifiers. It serves for the
production of high temperatures (in smelting of metals). Further, when
carburetted and also when carefully purified in an uncarburetted state,
it serves as an illuminant. The producer gas generated at the same time
is used for heating purposes (generally for heating boilers).

_Dowson gas._—Dowson gas is obtained by collecting and storing together
the gases produced in the manner described for water gas. Under the
grating of the wrought-iron gas producer (lined with firebrick and
similarly filled with coke or anthracite) a mixture of air and steam,
produced in a special small boiler, is blown through by means of a
Körting’s injector.

Before storage the gas is subjected to a purifying process similar to
that in the case of water gas. The mixed gas consists of 1 vol. water gas
and 2-3 vols. producer gas, with about 10-15 vols. per cent. H, 22-27
vols. per cent. CO, 3-6 per cent. CO₂, and 50-55 per cent. N. It is an
admirable power gas for driving gas motors (fig. 18).

_Mond gas_ similarly is a mixed gas obtained by blowing much superheated
steam into coal at low temperature. Ammonia is produced at the same time.

[Illustration: FIG. 18.—Power Gas Installation (_after Lueger_)

    A Steam boiler
    a Steam injector
    B Furnace
    b Charging hopper
    c Cover g
    d Valve C
    e Cock D
    f Vent pipe
    g Steam Pipe
    C Washer
    D Coke tower
    E Sawdust purifier]

_Suction gas._—In contradistinction to the Dowson system, in which air
mixed with steam is forced into the producer by a steam injector, in the
suction gas plant the air and steam are drawn into the generator by the
apparatus itself. The whole apparatus while in action is under slight
negative pressure. A special steam boiler is unnecessary because the
necessary steam is got up in a water container surrounding or connected
with the cover of the generator. The plant is set in motion by setting
the fire in action by a fan.

[Illustration: FIG. 19.—Suction Gas Plant (_after Meyer_)]

Fig. 19 shows a suction gas plant. B is the fan. Above the generator
A and at the lower part of the feed hopper is an annular vessel for
generating steam, over the surface of which air is drawn across from
the pipe e, passing then through the pipe f into the ash box g, and
then through the incandescent fuel. The gas produced is purified in the
scrubber D, and passes then through a pipe to the purifier containing
sawdust and to the motor.

_Carburetted gas._—Gas intended for illuminating purposes is carburetted
to increase its illuminating power, i.e. enriched with heavy
hydrocarbons. Carburetting is effected either by a hot method—adding the
gases distilled from mineral or other oils—or by a cold method—allowing
the gas to come into contact with cold benzol or benzine. Coal gas as
well as water gas is subjected to the carburetting process, but it
has not the same importance now in relation to illuminating power, as
reliance is more and more being placed on the use of mantles.


ACETYLENE

_Calcium carbide._—Acetylene is prepared from calcium carbide, which on
contact with water gives off acetylene.

_Calcium carbide_ is prepared electro-chemically. A mixture of burnt lime
and coke is ground and melted up together at very high temperature in an
electric furnace, in doing which there is considerable disengagement of
carbonic oxide according to the equation:

    CaO + 3C = CaC₂ + CO.

The furnaces used in the production of calcium carbide are of different
construction. Generally the furnace is of the nature of an electric arc,
and is arranged either as a crucible furnace for intermittent work or
like a blast furnace for continuous work.

Besides these there are resistance furnaces in which the heat is created
by the resistance offered to the passage of the current by the molten
calcium carbide.

The carbonic oxide given off in the process causes difficulty. In many
furnaces it is burnt and so utilised for heating purposes. The calcium
carbide produced contains as impurities silicon carbide, ferro-silicon,
calcium sulphide, and calcium phosphide.

_Acetylene_ (C₂H₂), formed by the decomposition of calcium carbide by
means of water (CaC₂ + 2H₂O = Ca(OH)₂ + C₂H₂), furnishes when pure an
illuminating gas of great brilliancy and whiteness. Its production is
relatively easy. Used for the purpose are (1) apparatus in which water
is made to drop on the carbide, (2) apparatus in which the carbide dips
into water and is removed automatically on generation of the gas, (3)
apparatus in which the carbide is completely immersed in water, and (4)
apparatus in which the carbide in tiny lumps is thrown on to water. These
are diagrammatically represented in figs. 20A to 20D.

[Illustration: FIG. 20A.

FIG. 20B.

FIG. 20C.

FIG. 20D.

Acetylene Apparatus—diagrammatic (_after Lueger_) A Dripping; B Dipping;
C Submerging; D Throwing in]

The most important impurities of acetylene are ammonia, sulphuretted
hydrogen gas, and phosphoretted hydrogen. Before use, therefore, it
is subjected to purification in various ways. In Wolf’s method the
gas is passed through a washer (with the object of removing ammonia
and sulphuretted hydrogen gas) and a purifying material consisting
of chloride of lime and bichromate salts. In Frank’s method the gas
passes though a system of vessels containing an acid solution of copper
chloride, and also through a washer. Chloride of lime with sawdust is
used as a purifying agent. Finally, the gas is stored and thence sent to
the consumer (see fig. 21).

[Illustration: FIG. 21.—Acetylene Gas Apparatus (_after Lueger_)]

EFFECTS ON HEALTH.—Almost all the poisoning caused in the industries in
question is due to carbonic oxide gas, of which water gas contains 41 per
cent., generator gas 35 per cent., and suction and Dowson gas 25 per cent.

That industrial carbonic oxide poisoning is not rare the reports of the
certifying surgeons in Great Britain sufficiently show. In the year 1906
fifty-five persons are referred to as having suffered, with fatal issue
in four. In 1907 there were eighty-one, of which ten were fatal. Of the
1906 cases twenty resulted from inhalation of producer, Mond, or suction
gas, sixteen from coal gas (in several instances containing carburetted
water gas), seventeen from blast furnace gas, and one each from charcoal
fumes from a brazier, and from the cleaning out of an oil gas holder.

As causes of the poisoning from suction gas were (1) improper situation
of gas plant in cellar or basement, allowing gas to collect or pass
upward; (2) defective fittings; (3) starting the suction gas plant by the
fan with chimney valve closed; (4) cleaning out ‘scrubbers’ or repairing
valves, &c.; (5) defective gasometer. In the seventeen cases due to blast
furnace gas six were due to conveyance of the gas by the wind from a flue
left open for cleaning purposes into an engineering shed, two to charging
the cupola furnace, two to entering the furnace, and four to cleaning the
flues.

The following are instances taken from recent literature on gas
poisoning[1]: Several cases of poisoning by _water gas_ occurred in a
smelting works. The poisoning originated when a blowing machine driven
by water gas was started. Owing to premature opening of the gas valve
two men employed in a well underneath the machine were overcome. The
attendant who had opened the valve succeeded in lifting both from the
well; but as he was trying to lift a third man who had come to his
assistance and fallen into the well he himself fell in and was overcome.
The same fate befell the engineer and his assistant who came to the
rescue. All efforts to recover the four men by others roped together
failed, as all of them to the number of eight were rendered unconscious.
With the aid of rescue appliances (helmets, &c.) the bodies were
recovered, but efforts at artificial respiration failed.

A workman was killed by _suction gas_ while in the water-closet. It
appeared that some time previously when the plant was installed the
ventilating pipe between the purifier and motor, instead of being led
through the roof, had been led out sideways on a level with the floor
immediately above the closet.

In another case the suction gas attendant had taken out the three-way
cock between the generator and motor for repairs and had not reinserted
it properly, so that when effort was made to start the motor this
failed, as gas only and no air was drawn in. The motor was thought to
be at fault, and the fan was worked so vigorously that the gas forced
its way out through the packing of the flange connections and produced
symptoms of poisoning in the persons employed.

More dangerous than suction gas plants, in which normally no escape
takes place, are installations depending on gas _under pressure_. Such
an installation was used for heating gas irons in a Berlin laundry. The
arrangements were considered excellent. The gas jets were in stoves
from which the fumes were exhausted. The gas was made from charcoal
and contained 13 per cent. of hydrogen. No trace of carbonic oxide was
found in the ironing room on examination of the air. After having been
in use for months the mechanical ventilation got out of order, with the
result that twelve women suffered severely from symptoms of carbonic
oxide poisoning, from which they were brought round by oxygen inhalation.
The laundry reverted to the use of illuminating gas. The conclusion
to be drawn is that installations for gas heating are to be used with
caution.[2]

Industrial poisoning from _blast furnace gas_ is frequent. Two fatal
cases were reported[3] in men employed in the gas washing apparatus. They
met their death at the manhole leading to the waste-water outlet. In
another case a workman entered the gas main three hours after the gas had
been cut off to clear it of the dust which had collected. He succumbed,
showing that such accumulations can retain gas for a long time. Steps had
been taken three hours previously to ventilate the portion of gas main in
question.

A fatal case occurred in the cleaning out of a blast furnace flue which
had been ventilated for 1½ hours by opening all manholes, headplates, &c.
The foreman found the deceased with his face lying in the flue dust; both
he and a helper were temporarily rendered unconscious.

Cases of poisoning by _generator gas_ are described.[4] A workman who had
entered a gasometer containing the gas died in ten minutes, and another
remained unconscious for ten days and for another ten days suffered from
mental disturbance, showing itself in hebetude and weakness of memory.

_Acetylene_ is poisonous to only a slight extent. Impurities in it, such
as carbon bisulphide, carbonic oxide (present to the extent of 1-2 per
cent.), and especially phosphoretted hydrogen gas, must be borne in mind.

American calcium carbide[5] yields acetylene containing 0·04 per cent. of
phosphoretted hydrogen; Lunge and Cederkreutz have found as much as 0·06
per cent. in acetylene.


AMMONIA AND AMMONIUM COMPOUNDS

PREPARATION.—Ammonia and ammonium salts are now exclusively obtained as
a bye-product in the dry distillation of coal, from the ammonia water in
gas works, and as a bye-product from coke ovens.

The ammonia water of gas works contains from 2-3 per cent. of ammonia,
some of which can be recovered on boiling, but some is in a non-volatile
form, and to be recovered the compound must be decomposed. The volatile
compounds are principally ammonium carbonate and, to a less extent,
ammonium sulphide and cyanide; the non-volatile compounds are ammonium
sulphocyanide, ammonium chloride, sulphate, thiosulphate, &c. Other
noteworthy substances in ammonia water are pyridine, pyrrol, phenols,
hydrocarbons, and tarry compounds.

Decomposition of the non-volatile compounds is effected by lime. Hence
the ammonia water is distilled first alone, and then with lime. The
distillate is passed into sulphuric acid, ammonium sulphate being formed.
Distillation apparatus constructed on the principle usual in rectifying
spirit is used, so that continuous action is secured; the ammonia water
flows into the apparatus continuously and is freed of the volatile
compounds by the steam. At a later stage milk of lime is added, which
liberates the ammonia from the nonvolatile compounds.

Of the ammonium salts there require mention:

_Ammonium sulphate_ ((NH₄)₂SO₄), which serves for the production of other
ammonium salts. It is usually centrifugalised out from the sulphuric acid
tank previously described.

_Ammonium chloride_ (sal-ammoniac, NH₄Cl) is formed by bringing the
ammonia fumes given off in the process described in contact with
hydrochloric acid vapour. The crude salt so obtained is recrystallised or
sublimed.

_Ammonium phosphate_ ((NH₄)₂HPO₄) is made in an analogous manner by
leading ammonia into phosphoric acid. It is useful as an artificial
manure.

_Ammonium carbonate_ is made either by bringing together ammonia vapour
and carbonic acid or by subliming ammonium sulphate with calcium
carbonate. It is very volatile. The thick vapour is collected and
purified in leaden chambers.

[Illustration: FIG. 22.—Preparation of Ammonia. Column Apparatus of
Feldman (_after Ost_)

A, B, C Columns; D Saturator; (a) Settling tank and regulator for flow of
ammonia; (b) Economiser; (f) Milk of lime; (g) Pump]

_Caustic ammonia_ is prepared either from gas liquor or, more usually,
from ammonium sulphate by distillation with caustic alkali in a
continuous apparatus.

USE OF AMMONIA.—Ammonia is used in laundries and bleaching works in
dyeing and wool washing. It is used especially in making ammonium salts,
in the preparation of soda by the Solvay process (see Soda Manufacture),
and in making ice artificially.

It is used also in the preparation of indigo, in lacquers and colours,
and the extraction of chloride of silver, &c.

EFFECTS ON HEALTH.—Industrial ammonia poisoning is rare. It occurs
most frequently in gas works and occasionally in its use, especially
the manufacture of ammonium salts. Those engaged in subliming ammonium
carbonate incur special risk, but often it is not the ammonia vapour so
much as the escaping evil-smelling gases containing carbon bisulphide and
cyanogen compounds which are the source of trouble.

Occasionally in the production of ice through leakage or by the breaking
of carboys of ammonia accidental poisoning has occurred.

Some cases are cited from recent literature:

A worker was rendered unconscious and drowned in an ammonia water
well.[1] Two workers were poisoned (one fatally) in the concentration of
gas liquor. Three workers were gassed (one fatally) in the preparation
of ammonium sulphate in a gas works. Probably as the result of excessive
steam pressure gas water was driven over with the ammonia into the
sulphuric acid vessel.[2]

Eulenberg[3] reports the occurrence of sulphuretted hydrogen gas
poisoning in the production of ammonium salts. The workers succumbed as
though shot, although work was being carried on in the open air. They
recovered when removed from the poisonous atmosphere.

In a large room of a chemical factory phosphoric acid was being saturated
with ammonia gas water in an iron lead-lined vessel. Carbonic acid gas
and hydrogen gas were evolved, but not to such extent as to be noticeable
in the large room. A worker not employed in the room had to do something
close to the vessel, and inhaled some of the fumes given off. A few
yards from the vessel he was found lying unconscious, and although
removed into the open air failed to respond to the efforts at artificial
respiration.[4]

Lewin, in an opinion delivered to the Imperial Insurance Office,
describes poisoning in a man who during two days had been employed
repairing two ammonia retorts in a chemical factory. On the evening of
the second day he suffered from severe symptoms of catarrh, from which
he died five days later. Lewin considered the case to be one of acute
ammonia poisoning.[5]

Ammonia is frequently used in _fulling_ cloth, the fumes of which collect
on the surface after addition of sulphuric acid to the settling vats.
This is especially liable to occur on a Monday, owing to the standing
of the factory over the Sunday, so that entrance into the vats without
suitable precautions is strictly forbidden. Despite this, a worker did
go in to fetch out something that had fallen in, becoming immediately
unconscious. A rescuer succumbed also and lost his life. The first worker
recovered, but was for long incapacitated by paralytic symptoms.

Cases of poisoning in _ice factories_ and refrigerator rooms from
defective apparatus are reported.

Acute and chronic poisoning among sewer men are due mainly to
sulphuretted hydrogen gas and only partly to ammonia. The more ammonia
and the less sulphuretted hydrogen sewer gases contain the less poisonous
are they.


CYANOGEN COMPOUNDS

TREATMENT OF THE MATERIALS USED IN GAS PURIFYING.—Cyanogen compounds
are still sometimes prepared by the original method of heating to
redness nitrogenous animal refuse (blood, leather, horn, hair, &c.) with
potash and iron filings; potassium cyanide is formed from the nitrogen,
carbon, and alkali, and this with the sulphur and iron present is easily
converted into potassium ferrocyanide (yellow prussiate of potash,
K₄FeC₆N₆) by lixiviation of the molten mass. It crystallises out on
evaporation.

Cyanogen compounds are obtained in large quantity from the material
used in purifying the gas in gas works. This saturated spent material
contains, in addition to 30-40 per cent. of sulphur, 8-15 per cent. of
cyanogen compounds and 1-4 per cent. of sulphocyanogen compounds.

By lixiviation with water the soluble ammonium salts are extracted from
the purifying material. This solution furnishes _sulphocyanide of
ammonium_, from which the remaining unimportant sulphocyanide compounds
are obtained (used in cloth printing). The further treatment of the
purifying material for potassium ferrocyanide is rendered difficult
because of the sulphur, which is either removed by carbon bisulphide
and the ferrocyanide obtained by treatment with quicklime and potassium
chloride, or the mass is mixed with quicklime, steamed in closed vessels,
lixiviated with water, and decomposed by potassium chloride; ferrocyanide
of potassium and calcium separates out in crystals, and this, treated
with potash, yields potassium ferrocyanide.

The well-known non-poisonous pigment Prussian blue is obtained by
decomposing ferrocyanide of potash with chloride or oxide of iron in
solution.

_Potassium cyanide_ (KCN) is prepared from potassium ferrocyanide by
heating in absence of air, but it is difficult to separate it entirely
from the mixture of iron and carbon which remains. All the cyanogen is
more easily obtained in the form of potassium and sodium cyanide from
potassium ferrocyanide by melting it with potash and adding metallic
sodium.

The very poisonous _hydrocyanic acid_ (prussic acid, HCN) is formed by
the action of acids on potassium or sodium cyanide; small quantities
indeed come off on mere exposure of these substances to the air. The
increasing demand for potassium cyanide has led to experimental processes
for producing it synthetically.

One method consists in the production of potassium cyanide from potash
and carbon in a current of ammonia gas. Small pieces of charcoal are
freed from air, saturated with a solution of potash, dried in the absence
of air, and heated in upright iron cylinders to 100° C., while a stream
of ammonia gas is passed through.

Again, sodium cyanide is prepared from ammonia, sodium, and carbon by
introducing a definite amount of sodium and coal dust into melted sodium
cyanide and passing ammonia through. The solution is then concentrated in
vacuo and sodium cyanide crystallises out on cooling.

USE OF CYANIDES.—Potassium cyanide is principally used in the recovery
of gold, in gold and silver electroplating, in photography, for
soldering (it reduces oxides and makes metallic surfaces clean), for
the production of other cyanogen compounds, for the removal of silver
nitrate stains, &c. Hydrocyanic acid gas is given off in electroplating,
photography, in smelting fumes, in tanning (removing hair by gas lime),
&c.

EFFECTS ON HEALTH.—Industrial cyanogen poisoning is rare. Weyl[1] states
that he could find no case in any of the German factory inspectors’
reports for the twenty years prior to 1897, nor in some twenty-five
volumes of foreign factory inspectors’ reports. I have found practically
the same in my search through the modern literature.

Of the very few references to the subject I quote the most important.

A case of (presumably) chronic hydrocyanic acid poisoning is described in
a worker engaged for thirteen years in silver electroplating of copper
plates.[2] The plates were dipped in a silver cyanide solution and then
brushed. After two years he began to show signs of vomiting, nausea,
palpitation, and fatigue, which progressed and led to his death.

A case of sudden death is described[3] occurring to a worker in a sodium
cyanide factory who inhaled air mixed with hydrocyanic acid gas from a
leaky pipe situated in a cellar. The factory made sodium cyanide and
ammonium sulphate from the residue after removal of the sugar from
molasses. This is the only definite case of acute cyanogen poisoning in a
factory known to me. I believe that under modern conditions, in which the
whole process is carried on under negative pressure, chance of escape of
cyanogen gases is practically excluded.

It should be mentioned that hydrocyanic acid vapour is given off in the
burning of celluloid. In this way eight persons were killed at a fire in
a celluloid factory.[4]

Skin affections are said to be caused by contact with fluids containing
cyanogen compounds, especially in electroplating. It is stated that
workers coming into contact with solutions containing cyanides may
absorb amounts sufficient to cause symptoms, especially if the skin
has abrasions. Such cases are described.[5] In electroplating, further,
in consequence of the strong soda solutions used, deep ulceration and
fissures of the skin of the hand can be caused.


COAL TAR AND TAR PRODUCTS

Of the products of the illuminating gas industry tar has considerably the
most importance. Coal tar as such has varied use in industry, but far
greater use is made of the products obtained by fractional distillation
from it such as benzene, toluene, naphthalene, anthracene, carbolic acid,
pyridine, and the other constituents of tar, a number of which form the
starting-point in the production of the enormous coal-tar dye industry.
Especially increasing is the consumption of benzene. In Germany alone
this has increased in ten years from 20 to 70 million kilos. This is
partly due to the need of finding some cheap substitute for benzine, the
consumption and cost of which has increased, and it has in many respects
been found in benzene.

Besides benzene and its homologues, toluene, anthracene, and naphthalene
are valuable. Anthracene is used in the manufacture of alizarine and
naphthalene in that of artificial indigo and of the azo-colours. Carbolic
acid (phenol) and the homologous cresols serve not only as disinfectants
but also in the manufacture of numerous colours and in the preparation
of picric acid and salicylic acid. Further, a number of pharmaceutical
preparations and saccharin are made from the constituents of tar.

The important _constituents of tar_ are:

1. Hydrocarbons of the methane series: paraffins, olefines; hydrocarbons
of the aromatic series: benzene and its homologues, naphthalene,
anthracene, phenanthrene, &c.

2. Phenols (cresols, naphthols).

3. Sulphides: sulphuretted hydrogen, carbon bisulphide, mercaptan,
thiophene.

4. Nitrogen compounds: ammonia, methylamine, aniline, pyridine, &c.

5. Fifty to sixty per cent. of tar consists of pitch constituting a
mixture of many different substances which cannot be distilled without
decomposition.

_Crude tar_, i.e. tar which separates in the dry distillation of coal,
is employed as such for preserving all kinds of building materials,
for tarring streets, as plastic cement, as a disinfectant, in the
preparation of roofing paper or felt, lampblack, briquettes, &c.

_Brattice cloth_ and _roofing felt_ are made by passing the materials
through hot tar and incorporating sand with them; in doing this heavy
fumes are given off.

_Lampblack_ is made by the imperfect combustion of tar or tar oil by
letting them drop on to heated iron plates with as limited an air supply
as possible; the burnt gases laden with carbon particles are drawn
through several chambers or sacks in which the soot collects.

[Illustration: FIG. 23.—Tar Still (_after Krämer_)]

_Briquettes_ (patent fuel) are made by mixing small coal (coal dust) with
tar or pitch and then pressing them in moulds.

The separation and recovery of the valuable ingredients is effected by
_fractional distillation_. This is carried out by heating the tar at
gradually increasing temperature in a wrought-iron still, the bottom
of which is arched and having a cast-iron still head, or in horizontal
boilers by direct fire. Before commencing the distillation the tar is
freed as far as possible of water by storage. On gradual increase of
temperature the volatile constituents, the so-called ‘light oil,’ and
later the heavier volatile constituents come over. The constituents are
liberated in a gaseous state and are collected in fractions. The pitch
remains behind in the still. Considerable quantities of coal tar are not
distilled for pitch. Often the light oils and a portion of the heavy oils
are collected, when soft pitch remains, or, if the light oils and only
a very small portion of the heavy oils are collected, _asphalt_ remains
behind, this residue being used as a basis for the manufacture of roofing
felt. The vapours are condensed in iron coils round which cold water
circulates. The receivers in which the distillate is caught are changed
at definite times as the temperature gradually rises. If five fractions
have come over they are called (1) first runnings, (2) light oil to 170°
C., (3) middle oil (carbolic oil to 230° C.), (4) heavy oil to 270° C.,
and lastly (5) anthracene oil, which distills at over 270° C.; the pitch
remaining behind is let out of the still by an opening at the bottom.

We will briefly sketch the further treatment and use of these fractions,
so far as a knowledge of the most important processes is necessary for
our purpose.

1. The _light oils_ (including first runnings) coming over up to 170° C.
are again distilled and then purified with sulphuric acid in lead-lined
cast-iron or lead-lined wooden tanks. The dark-coloured acid used for
purifying after dilution with water, which precipitates tarry matters,
is treated for ammonium sulphate; the basic constituents of the light
oils extracted with sulphuric acid and again liberated by lime yield
_pyridine_ (C₅H₅N) and the homologous pyridine bases, a mixture of which
is used for denaturing spirit. After the light oils have been washed
with dilute caustic soda liquor, whereby the phenols are removed, they
are separated by another fractional distillation into (_a_) crude benzol
(70°-130° C.) and (_b_) solvent naphtha (boiling-point 130°-170° C.).

_Crude benzol_ (70°-140° C.) consists chiefly of benzene and toluene
and is separated into its several constituents in special rectifying
apparatus. For this production of pure benzene (boiling-point 80°-82° C.)
and pure toluene (boiling-point 110° C.) fractionating apparatus is used
(fig. 24).

The _commercial products_ in use which are obtained from the fractional
distillation of the light oil are:

(_a_) _Ninety per cent. benzol_, so called because in the distillation 90
per cent, should come over at a temperature of 100° C. It is made up of
80-85 per cent. benzene, 13-15 per cent. toluene, 2-3 per cent. xylene,
and contains, as impurities, traces of olefines, paraffins, sulphuretted
hydrogen, and other bodies.

(_b_) _Fifty per cent. benzol_ contains 50 per cent. of constituents
distilling at 100° C. and 90 per cent. at 120° C.; it is a very mixed
product, with only 40-50 per cent. of benzene.

(_c_) _Solvent naphtha_, so called because it is largely used for
dissolving rubber, is free from benzene, but contains xylene and its
homologues and other unknown hydrocarbons.

[Illustration: FIG. 24.—Column Apparatus of Hickman for Distillation of
Benzene (_after Ost_)

A Still body; B Analysing column; C Cooler; D Condenser for pure
distillate.]

Benzol is widely used. Ninety per cent. benzol is largely used in
the chemical industry, serving for the preparation of dye stuffs,
pharmaceutical preparations, scents, &c. In other industries it took the
place of benzine and also of turpentine oil, especially in the paint
industry, since it evaporates quickly and readily dissolves resins.
Hence it is used in the preparation of quick drying ship’s paints, as a
protection against rust, and as an isolating lacquer (acid proof colours)
for electrical apparatus, in the production of deck varnishes, and as a
solvent of resins.

This use of benzol in the paint industry is by no means unattended with
danger, as benzol is poisonous. Far less harmful, if not altogether
without risk, is use of benzol free solvent naphtha—but this evaporates
only slowly and hence cannot take the place of benzol.

Benzol serves further for fat extraction from bones in manure factories
and of caffein from coffee beans.

Again, it is used as a motive power in motor vehicles.

The solvent naphtha above mentioned with boiling-point above 140° C. and
all the light oils are employed in chemical cleaning and for dissolving
indiarubber (see Indiarubber).

These are known in the trade erroneously as ‘benzine,’ which
unfortunately often leads to confusion with petroleum benzine (see
Petroleum) and to mistakes in toxicological accounts of poisoning.

2. Between 150° and 200° C. the _middle oil_ comes over, from which on
cooling _naphthalene_ (C₁₀H₈) crystallises out, and is subsequently
washed with caustic soda liquor and with acid; it is re-distilled and
hot pressed. The remaining liquor yields, when extracted with caustic
soda, _phenol_ (carbolic acid, C₆H₅OH), which, on addition of sulphuric
acid or carbonic acid, separates from the solution and then—generally in
special factories—is obtained pure by distillation and special purifying
processes.

From the sodium salt of carbolic acid (sodium phenolate) _salicylic
acid_ (C₆H₄OH.COOH) is obtained by combination with compressed CO₂ at a
temperature of 150° C. _Picric acid_ (trinitrophenol, C₆H₂OH.(NO₂)₃) is
obtained by treating phenol with a mixture of sulphuric and nitric acids
(nitration). The yellow crystals of this explosive which separate are
carefully washed, recrystallised, centrifugalised, and dried.

3. The _heavy oils_ which come over between 200° and 300° C. containing
cresols, naphthols, naphthaline, quinoline bases, fluid paraffins, &c.,
are seldom separated further. The disinfectants lysol, sapocarbolic, &c.,
are obtained from such fractions.

The heavy oils are much in use for _impregnating wood_ (piles, railway
sleepers, &c.), to prevent rotting. This is done in special creosoting
installations. The wood is first freed from moisture under vacuum and
lastly the heavy oil forced in. This is a better means of preserving
timber than the analogous method by means of chloride of zinc.

4. _Anthracene oil_ or ‘green oil’ comes over between 300° and 400° C.
and contains the valuable anthracene which crystallises out, is separated
from the oil in filter presses, or dried in centrifugal machines.
_Alizarin_ dyes are made from it. Raw anthracene oil further is used
commercially as a paint under the name of carbolineum for preserving wood.

5. The _pitch_ remaining behind in the still serves (like tar) for
making varnishes, patent fuel, &c. For our purpose use of pitch in
the preparation of iron varnishes which adhere to metals and protect
them from oxidation have interest. Pitch and the heavy oils are melted
together or, if for thin varnishes, dissolved in solvent naphtha. The
volatile constituents evaporate after the coat has been applied.

EFFECTS ON HEALTH.—Severe injury to health or poisoning cases scarcely
arise through manipulations with or use of tar. Inhalation, however, of
large quantities of tar vapour is without doubt unpleasant, as a number
of poisonous substances are contained in the fumes. And the ammonia water
which separates on standing can give off unpleasantly smelling odours
from the sulphur compounds in it, especially if it comes into contact
with waste acids, with consequent development of sulphuretted hydrogen
gas.

I could not find in the literature of the subject references to any
clearly proved case of poisoning from tar emanations. But deserving of
mention in this connection are the _effects on the skin_ caused by tar.

Workers coming into contact with tar suffer from an inflammatory
affection of the skin, so-called tar eczema, which occasionally takes
on a cancerous (epithelioma) nature similar to chimney-sweep’s cancer,
having its seat predominantly on the scrotum. In lampblack workers who
tread down the soot in receptacles the malady has been observed to affect
the lower extremities and especially the toes.

In tar distillation and in the _production_ and _use_ of _benzene_
industrial poisoning frequently occurs. Many cases are recorded, but in
several the immediate exciting cause is doubtful, and consequently it is
often difficult to classify the cases.

Most frequently the manufacture and use of benzene come in question.
Besides this, in tar distillation poisoning may be caused by other
substances, such as sulphuretted hydrogen gas, carbonic oxide gas, &c. In
the production of antipyrin, aspirin, &c., and in the preparation and use
of anthracene injury to health is recognised.

From the list of recognised cases of these forms of poisoning the most
characteristic are chosen from the recent literature on the subject.

The Prussian factory inspectors’ reports for 1904 describe the following:
In cleaning out a tar still two workers were killed by inhalation of gas.
The nature of the gas was not ascertained. But what probably happened was
that the cock on the foul gas pipe collecting the gases from the stills
leaked and allowed fumes to pass over from one still to another.

A foreman and worker were rendered unconscious on entering a receiver
for heavy oil for cleaning purposes. On treatment with oxygen gas they
speedily recovered.

_Industrial benzene poisoning_ is especially frequent now in view of the
increasing use to which it is put. Several cases have proved fatal.

A worker, for instance, forgot to open the cock for the water to cool the
condenser, so that some of the benzene vapour remained uncondensed. The
case proved fatal.

The Report of the Union of Chemical Industry for 1905 stated that a
worker on night duty, whose duty it was to regulate the introduction
of steam and the cooling of the benzol plant, was found lying dead in
front of the building. Inquiry showed that he had not opened the valve
for running the distillate into the appropriate receiver. Eight thousand
litres overflowed.

In an indiarubber extracting factory a worker was rendered unconscious
while inspecting a benzol still; before entering he had omitted to
observe the instructions to drive steam through and have a mate on watch
at the manhole. Two other workmen were similarly affected who went to the
rescue without adoption of precautions. Only one survived.

In a further accident (already mentioned under ‘Coke Furnaces’) two
workmen were killed. In the factory in question the thick tar from the
coke ovens was being distilled under slight pressure. The air pumps,
however, were out of order, and temporary use was being made of Körting’s
injectors, whereby the steam and tar constituents were cooled and led
into the drain in front of the closet, near to which was a ventilating
shaft. Probably, in addition to benzene and its homologues, sulphuretted
hydrogen and cyanogen compounds were present in the poisonous gases.

In cleaning out a benzene extracting apparatus a workman was killed by
the stagnant fumes in it.

A similar case of benzene poisoning occurred in a naphthalamine works
through inspecting an extracting vessel which had contained benzene
and naphthalamine and had to be cleaned. The vessel had been empty for
twenty-two hours and had been washed and ventilated, but through a
leaking pipe benzene had dropped down into it. The workman engaged was
rendered unconscious inside the retort, but was rescued by an engineer
equipped with a breathing helmet. Others who without such apparatus tried
to effect a rescue were overcome, and one who had entered the retort
succumbed.[1]

Benzene poisoning has often occurred in the cleaning of tanks, &c., for
the transport and storage of the substance. The following examples are
taken from the Reports of the Union of Chemical Industry.

A worker during the pause for breakfast had, unknown to his employer,
cleaned out an empty truck for crude benzol. Later he was with difficulty
removed unconscious through the manhole and could not be resuscitated.
Only a short time previously a similar occurrence had taken place in the
same factory.

Two further fatal cases were reported in 1908 in the cleaning out of
railway tank waggons. The tank had previously been thoroughly sprayed
with water. The partition plates which are required in such tanks
increase the difficulty of cleaning from the manhole. After the foreman
had tested the air by putting his head inside and considered it free from
danger, a man entered to clean out the deposit; another man on watch
outside had evidently gone in for rescue purposes. Resuscitation in both
cases failed.

A worker died and several were affected in the cleaning out of a benzol
storage tank in a tar distillery. The tank had had air blown through it
several weeks before, and had been thoroughly cleaned by steam and water.
Also in the inspection the greatest care was taken in only permitting
work for short spells. This shows that, notwithstanding great care, the
last traces of benzol cannot be entirely removed and that quite small
quantities are sufficient to cause severe and even fatal poisoning.
Workers should only clean out tanks, therefore, when properly equipped
with helmets.

In the German factory inspectors’ reports for 1902 a case of intoxication
is described in a man who was engaged painting the inside of an iron
reservoir with an asphalt paint dissolved in benzol.

Of special interest is a fatal case from inhalation of benzol fumes in
a rubber factory. Rubber dissolved in benzol was being rubbed into the
cloth on a spreading machine in the usual way. The cloth then passes
under the cleaning doctor along the long heated plate to the end rolls.
Of the three men employed at the process one was found to be unconscious
and could not be brought round again.

The cases described[2] of poisoning with impure benzol in a pneumatic
tyre factory in Upsala are, perhaps, analogous. Here nine young women had
severe symptoms, four of whom died.

In reference to the cases which occurred in rubber factories it is
conceivable that carbon bisulphide played a part, since in such factories
not only are mixtures of benzol and carbon bisulphide used, but also
frequently the ‘first runnings’ of benzol, which, on account of the high
proportion (sometimes 50 per cent.) of carbon bisulphide in them, make an
excellent solvent for rubber.

From some coke ovens crude benzol was collected in two large iron
receivers. They were sunk in a pit projecting very little above the
ground. To control the valves the workmen had to mount on the receiver,
the manholes of which were kept open during filling. The pit was roofed
over and two wooden shafts served both for ventilation and as approaches
to the valves. One summer day benzol had been blown in the usual way
into a railway truck and a worker had entered the space to control the
valves. Some time afterwards he was found in a doubled-up position on
the receiver, grasping the valves, from which later he fell off down to
the bottom of the pit. Three rescuers entered, but had to retire as they
became affected. A fourth worker, in the presence of the manager, was let
down by a rope, but succumbed immediately and was dragged up a corpse.
Finally, equipped with a smoke helmet, a rescuer brought up the lifeless
body of the first man. It was believed that the benzol had distilled
over warm and had evaporated to such an extent as to fill with fumes the
unsuitably arranged and inadequately ventilated space. Possibly other
volatile compounds were responsible for the poisoning.[3]

A similar though less serious accident occurred to a foreman who forgot
to set the cooling apparatus at work at the commencement of distillation,
and became unconscious from the escaping fumes, as also did a rescuer.
The latter was brought round by oxygen inhalation, but the former,
although alive when recovered, succumbed despite efforts at artificial
respiration.

A fatal case occurred in an aniline factory where benzol fumes had
escaped owing to faulty arrangement of the valves. The worker, although
ordered at once to leave the room, was found there ten minutes later dead.

Interesting are the following cases of accidents due to use of paints
containing benzol.

In painting a retort with an anti-corrosive paint called ‘Original
Anti-corrosive,’ unconsciousness followed on completion of the painting,
but by prompt rescue and medical assistance life was saved. The accident
was attributed to benzol fumes from the paint insufficiently diluted by
the air coming in at the open manhole. A similar case arose from use
of a rust-preventing paint—‘Preolith’—and only with difficulty was the
man using it pulled out from the inside of the steam boiler. Although
resuscitated by oxygen inhalation, he was incapacitated for eight days.
Crude benzol was a constituent of ‘Preolith.’ Obviously use of such
paints in closely confined spaces is very risky.

The frequency of such poisonings caused Schaefer,[4] Inspector of
Factories in Hamburg, to go fully into the question. He lays stress on
the dangerous nature of paints containing a high proportion of benzol,
but considers use of unpurified constituents with boiling-point between
130°-170° C., such as solvent naphtha, as free from risk (cf. in Part II
the experiments on benzene and the commercial kinds of benzol). Schaefer
mentions that in 1903 and 1904 cases of unconsciousness from painting
the inside of boilers were numerous. The proportion of benzol in the
paints was 20-30 per cent. In 1905 and 1906 the cases were attributable
rather to inhalation of hydrocarbons in cleaning of apparatus. Use of
‘Dermatin’ affected two painters. One case in 1906 happened to a man
painting the double bottom of a ship in Hamburg harbour with ‘Black
Varnish Oil’ through the manhole, in doing which he inhaled much of the
fumes. This paint consisted of coal-tar pitch in light coal-tar oil, the
latter constituent (distilling at 170° C.) amounting to 31-33 per cent.
Investigation showed further that the bulk of the tar oil volatilised at
ordinary temperatures and so quickly dried. Sulphuretted hydrogen gas was
given off on slight warming. The person after using it for some time felt
poorly, and then became ill with severe inflammation of the respiratory
passages, which proved fatal after twenty-four days.

Several similar cases occurred in 1908 and 1909. Painting the inside
of a boiler with ‘Auxulin’ caused unconsciousness in four persons,
of whom three were rescuers. A fatal case was due to use of a patent
colour containing 30-40 per cent. benzol in an entirely closed-in space
(chain-well), although the worker was allowed out into fresh air at
frequent intervals.

A case of chronic industrial xylene poisoning is described in a worker
using it for impregnating indiarubber goods. The symptoms were nervous,
resembling neurasthenia.

Some of the cases of poisoning, especially when severe and fatal, in
the production of distillation constituents of coal tar are doubtless
attributable to _sulphuretted hydrogen gas_. Thus in England, in the
years 1901-3, there were eleven fatal and as many other severe cases
reported from tar distilleries, of which the majority were due to
sulphuretted hydrogen gas.

One case of _carbonic oxide_ poisoning in coal-tar distillation is
described.[5] In cleaning out pitch from a still fourteen days after the
last distillation a workman succumbed to carbonic oxide poisoning. This
is at all events a rare eventuality, since no other case is to be found
in the literature of the subject, but it is a proof that in the last
stage of coal-tar distillation carbonic oxide plays a part.

Mention must be made of the frequent occurrence of severe skin affections
in _anthracene workers_; they take the form of an eruption on the hands,
arms, feet, knees, &c., and sometimes develop into cancer.

Observations in a chemical factory since 1892 showed that of thirty thus
affected in the course of ten years twenty-two came into contact with
paraffin.


Artificial Organic Dye Stuffs (Coal-tar Colours)

MANUFACTURE.—The starting-points for the preparation of artificial
coal-tar dyes are mainly those aromatic compounds (hydrocarbons)
described in the preceding section. Besides these, however, there are the
derivatives of the fatty series such as methyl alcohol (wood spirit),
ethyl alcohol, phosgene, and, latterly, formaldehyde.

The _hydrocarbons of the benzene series_ from tar distillation are
delivered almost pure to the colour factory. Of these benzene, toluene,
xylene, naphthalene, anthracene, and the phenols, cresols, &c., have to
be considered.

Further treatment is as follows:

1. Nitration, i.e. introduction of a nitro-group by means of nitric acid.

2. Reduction of the nitrated products to amines.

3. Sulphonation, i.e. conversion to sulphonic acids by means of
concentrated sulphuric acid.

4. The sulphonic acids are converted into phenols by fusing with caustic
soda.

5. Introduction of chlorine and bromine.

_Nitro-derivatives_ are technically obtained by the action of a mixture
of nitric and concentrated sulphuric acids on the aromatic body in
question. The most important example is _nitrobenzene_.

Benzene is treated for several hours in cylindrical cast-iron pans with
nitric and concentrated sulphuric acids. The vessel is cooled externally
and well agitated. A temperature of 25° C. should not be exceeded.

[Illustration: FIG. 25.—Preparation of Intermediate Products in the
Aniline Colour Industry (Closed Apparatus), showing Arrangement for
Condensation (_after Leymann_)]

On standing the fluid separates into two layers: the lower consists of
dilute sulphuric acid in which there is still some nitric acid, and
the upper of nitrobenzene. The latter is freed of remains of acid by
washing and of water by distillation. _Toluene_ and _xylene_ are nitrated
in the same way. _Dinitro products_ (such as metadinitrobenzene) are
obtained by further action of the nitro-sulphuric acid mixture on the
mononitro-compound at higher temperature.

For conversion of phenol into _picric acid_ (trinitrophenol) the use of a
nitro-sulphuric acid mixture is necessary.

The _aromatic bases_ (aniline, toluidine, xylidine) are obtained by
reduction of the corresponding nitro-compound by means of iron filings
and acid (hydrochloric, sulphuric, or acetic). Thus in the case of
_aniline_ pure nitrobenzene is decomposed in an iron cylindrical
apparatus, provided with agitators and a condenser, and avoidance of a
too violent reaction, by means of fine iron filings and about 5 per cent.
hydrochloric acid. After completion of the reaction the contents are
rendered alkaline by addition of lime and the aniline distilled over.
Manufacture of _toluidine_ and _xylidine_ is analogous.

_Dimethylaniline_ is obtained by heating aniline, aniline hydrochloride,
and methyl alcohol.

_Diethylaniline_ is prepared in an analogous way with the use of ethyl
alcohol.

By the action of nitrous acid (sodium nitrite and hydrochloric acid) on
the acid solution of the last-named compound the _nitroso compounds_ are
formed.

_Sulphonic acids_ arise by the action of concentrated or fuming sulphuric
acid on the corresponding bodies of the aromatic series: benzene
disulphonic acid from benzene and fuming sulphuric acid, &c.

_Phenols_ and _cresols_ are obtained pure from tar distillation. The
remaining hydroxyl derivatives (resorcin, α- and β-naphthol, &c.), are
generally obtained by the action of concentrated caustic soda on aromatic
sulphonic acids.

The most important aromatic aldehyde, _benzaldehyde_, is obtained from
toluene; on introducing chlorine at boiling temperature benzyl chloride
is first formed, then benzal-chloride and finally benzo-trichloride. In
heating benzal-chloride with milk of lime (under pressure) benzaldehyde
is formed (C₆H₅COH).

_Picric acid_ and _naphthol yellow_ belong to the _nitro dyestuffs_; the
last named is obtained by sulphonating α-naphthol with fuming sulphuric
acid and by the action of nitric acid on the sulphonated mixture.

Nitroso derivatives of aromatic phenols yield (with metal oxides) the
material for production of nitroso dyestuffs. To these belong naphthol
green, &c.

The most important _azo dyestuffs_ technically are produced in principle
by the action of nitrous acid on the aromatic amines. The amido compound
is converted into the diazo salt by treatment with sodium nitrite in
acid solution. Thus diazo-benzene is made from aniline. Diazo compounds
are not usually isolated but immediately coupled with other suitable
compounds—amido derivatives, phenols—i.e. converted into azo compounds.

[Illustration: FIG. 26.—Nitrating Plant (_after Leymann_)

        I Nitric acid
       II Balance
      III Storage tank
       IV Nitrating pan
        V Waste acid tank
       VI Acid egg
      VII Hydrocarbon
     VIII Balance
       IX Storage tank
        X Washing vessel
       XI Centrifugal machine
      XII Egg
    - - - Exhaust ventilation pipe.]

The combination of the two constituents takes place at once and
quantitatively. The colour is separated from the aqueous solution by
salting-out, and is then put through a filter press. The reactions
are carried out generally in wooden vats arranged in stages. Besides
a second, a third constituent can be introduced, and in this way
naphthol—and naphthylamine sulphonic acids yield a large number of
colouring matters. A very large number of azo dyestuffs can thus be
produced by the variation of the first component (the primary base) with
the second and again with the third component, but it would carry us too
far to deal further with their preparation.

_Anthracene colours_—yielding so-called direct dyes—are prepared
from anthracene, which is converted into anthraquinone by the action
of bichromate and dilute sulphuric acid when heated; the crude
‘quinone’ is purified with concentrated sulphuric acid and converted
into anthraquinone monosulphonic acid to serve in the preparation of
_alizarin_, which is made from it by heating for several days with
concentrated caustic soda to which sodium chlorate is added. The process
is carried on in cast-iron pans provided with agitators.

_Alizarin_ is the starting-point for the alizarin dyes, but of their
production we will not speak further, as they, and indeed most of the
coal-tar dyes, are non-poisonous.

_Indigo_ to-day is generally obtained by synthesis. It is prepared from
phenylglycine or phenylglycine ortho-carboxylic acid, which on heating
with sodamide becomes converted into indoxyl or indoxyl carboxylic
acid. These in presence of an alkali in watery solution and exposure to
the oxygen of the air immediately form indigo. The necessary glycine
derivatives are obtained by the action of monochloracetic acid on aniline
or anthranilic acid, which again are derived from naphthalene (by
oxidation to phthalic acid and treatment of phthalimide with bleaching
powder and soda liquor).

_Fuchsin_ belongs to the group of triphenylmethane dyestuffs, with the
production of which the epoch of coal-tar colour manufacture began, from
the observation that impure aniline on oxidation gave a red colour. The
original method of manufacture with arsenic acid is practically given up
in consequence of the unpleasant effects which use and recovery of large
quantities of arsenic acid gave rise to. The method consisted in heating
a mixture of aniline and toluidine with a solution of arsenic acid under
agitation in cast-iron cylinders. The cooled and solidified mass from the
retorts was boiled, and from the hot solution, after filtration, the raw
fuchsin was precipitated with salt and purified by crystallisation.

Now by the usual nitrobenzene process, aniline, toluidine, nitrobenzene,
and nitrotoluene are heated with admixture of hydrochloric acid and some
iron protochloride or zinc chloride. Further treatment resembles the
arsenic process.

By alkylation, i.e. substitution of several hydrogen atoms of the
amido-groups by ethyl, &c., through the action of alkyl halogens
and others, it was found possible to convert fuchsin into other
triphenylmethane colours. But it was soon found simpler to transfer
already alkylated amines into the colours in question. Thus, for example,
to prepare _methyl violet_ dimethyl aniline was heated for a long time
with salt, copper chloride, and phenol containing cresol in iron mixing
drums. The product is freed from salt and phenol by water and calcium
hydrate, subsequently treated with sulphuretted hydrogen or sodium
sulphide, and the colour separated from copper sulphide by dissolving in
dilute acid.

Mention must be made, finally, of the _sulphur dyes_ obtained by heating
organic compounds with sulphur or sodium sulphide. For the purpose
derivatives of diphenylamine, nitro- and amido-phenols, &c., serve as the
starting-point.

EFFECTS ON HEALTH.—From what has been said of the manufacture of coal-tar
dyes it is evident that poisoning can arise from the initial substances
used (benzene, toluene, &c.), from the elements or compounds employed
in carrying out the reactions (such as chlorine, nitric acid, sulphuric
acid, arsenious acid, sodium sulphide, and sulphuretted hydrogen gas),
from the intermediate bodies formed (nitro and amido compounds, such as
nitrobenzene, dinitrobenzene, aniline, &c.), and that, finally, the end
products (the dyes themselves) can act as poisons. It has already been
said that most of the dyes are quite harmless unless contaminated with
the poisonous substances used in their manufacture.

We have seen that many of the raw substances used in the manufacture
of coal-tar dyes are poisonous, and we shall learn that several of the
intermediate products (especially the nitro and amido compounds) are so
also.

According to Grandhomme,[1] of the raw materials benzene is the one
responsible for most poisoning. He describes two fatal cases of benzene
poisoning. In one case the worker was employed for a short time in a room
charged with benzene fumes, dashed suddenly out of it, and died shortly
after. In the other, the workman was employed cleaning out a vessel in
which lixiviation with benzene had taken place. Although the vessel
had been steamed and properly cooled, so much benzene fume came off in
emptying the residue as to overcome the workman and cause death in a
short time.

Grandhomme describes no injurious effect from naphthalene nor, indeed,
from anthracene, which he considered was without effect on the workers.

Similarly, his report as to nitrobenzene was favourable. No reported case
of poisoning occurred among twenty-one men employed, in some of whom
duration of employment was from ten to twenty years. Aniline poisoning,
however, was frequent among them. In the three years there was a total
of forty-two cases of anilism, involving 193 sick days—an average of
fourteen cases a year and sixty-four sick days. None was fatal and some
were quite transient attacks.

In the fuchsin department no cases occurred, and any evil effects in the
manufacture were attributable to arsenic in the now obsolete arsenic
process. Nor was poisoning observed in the preparation of the dyes in
the remaining departments—blues, dahlias, greens, resorcin, or eosin. In
the manufacture of methylene blue Grandhomme points out the possibility
of evolution of arseniuretted hydrogen gas from use of hydrochloric acid
and zinc containing arsenic. Poisoning was absent also in the departments
where alizarine colours and pharmaceutical preparations were made.

Among the 2500-2700 workers Grandhomme records 122 cases of industrial
sickness in the three years 1893-5, involving 724 sick days. In addition
to forty-two cases of anilism there were seventy-six cases of lead
poisoning with 533 sick days. Most of these were not lead burners, but
workers newly employed in the nitrating department who neglected the
prescribed precautionary measures. Lastly, he mentions the occurrence of
chrome ulceration.

The frequency of sickness in the Höchst factory in each of the years
1893-5 was remarkably high: 126 per cent., 91 per cent., and 95 per
cent. Much less was the morbidity in the years 1899-1906—about 66 per
cent.—recorded by Leymann[2]—probably the same Höchst factory with 2000
to 2200 employed. And the cases of industrial poisoning also were less.
He cites only twenty-one in the whole of the period 1899-1906. Of these
twelve were due to aniline, involving thirty sick days, only five to lead
poisoning, with fifty-four sick days, one to chrome ulceration, one to
arseniuretted hydrogen gas (nine sick days), and one fatal case each from
sulphuretted hydrogen gas and from dimethyl sulphate. In 1899, of three
slight cases of aniline poisoning one was attributable to paranitraniline
(inhalation of dust), and the two others to spurting of aniline oil on
to the clothing, which was not at once changed. Of the four cases in
1900, one was a plumber repairing pipes conveying aniline and the others
persons whose clothes had been splashed.

In 1903 a worker employed for eleven and a half years in the aniline
department died of cancer of the bladder. Such cancerous tumours have
for some years been not infrequently observed in aniline workers, and
operations for their removal performed. Leymann thinks it very probable
that the affection is set up, or its origin favoured, by aniline. This
view must be accepted, and the disease regarded as of industrial origin.
Three slight cases in 1904 and 1905 were due partly to contamination of
clothing and partly to inhalation of fumes. Of the five cases of lead
poisoning three were referable to previous lead employment. Perforation
of the septum of the nose by bichromate dust was reported once only. A
fatal case from sulphuretted hydrogen gas and a case of poisoning by
arseniuretted hydrogen gas occurred in 1906, but their origin could not
be traced.

In large modern aniline dye factories, therefore, the health of the
workers is, on the whole, good and industrial poisoning rare. Comparison
of the two sets of statistics show that improvement in health has
followed on improved methods of manufacture. Such cases of aniline
poisoning as are reported are usually slight, and often accounted for by
carelessness on the part of the workers.

Data as to the health of workers in factories manufacturing or using
nitro compounds are given in the English factory inspectors’ reports
for 1905. Even with fortnightly medical examination in them, more than
half the workers showed signs of anæmia and slight cyanosis. Two men in
a factory employing twelve men in the manufacture of nitro compounds
were treated in hospital for cyanosis, distress of breathing, and general
weakness. One had only worked in the factory for nine days. In another
badly ventilated factory, of twenty persons examined fourteen showed
bluish-grey coloration of the lips and face, ten were distinctly anæmic,
and six showed tremor and weakness of grasp.

Nitrobenzene poisoning arises from the fumes present in aniline and
roburite factories. Acute and chronic poisoning by nitro compounds of
the benzene series are described, brought about by accident (fracture
of transport vessels) and by carelessness (splashing on to clothes).
Cases of optic neuritis (inflammation of the optic nerve) as a result of
chronic nitrobenzene poisoning are described.

Dinitrobenzene and other nitro and dinitro compounds are present
in safety explosives. Thus roburite and bellite consist of
metadinitrobenzene and ammonium nitrate; ammonite of nitronaphthalene and
ammonium nitrate; securite of the materials in roburite with ammonium
oxalate in addition. In roburite there may be also chlorinated nitro
compounds.

Leymann,[3] describing accidents in the preparation of nitrophenol
and nitrochloro compounds, mentions four fatal cases occurring in the
manufacture of black dyes from mono- and di-nitrophenols as well as
mono- and di-nitrochlorobenzene and toluene. In three of the cases
dinitrophenol was the compound at fault owing to insufficient care in
the preparation,—the result of ignorance until then of risk of poisoning
from mono- and tri-nitrophenol. One of the men had had to empty a washing
trough containing moist dinitrophenol. He suddenly became collapsed, with
pain in the chest, vomiting, fever, and convulsions, and died within
five hours. Another suffered from great difficulty of breathing, fever,
rapid pulse, dilatation of the pupils, and died within a few hours in
convulsions. Two further cases of nitrochlorobenzene poisoning are
referred to, one of which was fatal. Four chlorobenzene workers after a
bout of drinking were found unconscious in the street, and only recovered
after eight to ten hours in hospital. The symptoms were grey-blue colour
of the skin, pallor of mucous membranes, lips, nose, and conjunctivæ,
and peculiar chocolate-coloured blood.

Many cases of poisoning from roburite are recorded.[4] In the Witten
roburite factory it is stated that during the years 1890-7 almost all
the workers had been ill.[5] Only three looked healthy—all the others
suffered from more or less pallor, blue lips, and yellowish conjunctivæ.

A case of chlorobenzene poisoning was reported with symptoms of headache,
cyanosis, fainting attacks, difficulty of breathing, &c., in a man who
had worked only three weeks with the substance.[6]

In the nitrotoluene department of an explosives factory a number of
the workmen suffered from symptoms of distress in breathing, headache,
&c., of whom two, employed only a short time, died. The poisoning was
attributed, partly to nitrotoluene and partly to nitrous fumes. As a
contributing cause it was alleged that in view of shortage of hands
unsuitable persons were engaged who neglected precautions.[7]

Nitronaphthalene is said to cause inflammation and opacity of the
cornea,[8] attributable either to long-continued exposure (four to eight
months) to nitronaphthalene vapour or to spurting of the liquid into the
eye.

I could not find reference in literature to actual cases of poisoning by
picric acid. They are referred to in a general way only as causing skin
affections.

Aniline poisoning arises generally from inhalation, but absorption
through the skin and less frequently inhalation of dust of aniline
compounds cause it. We have already laid stress on the frequently severe
cases resulting from carelessness in spilling on to or splashing of,
clothes without at once changing them, breaking of vessels containing it,
and entering vessels filled with the vapour. In literature of old date
many such cases have been described, and it was stated that workers were
especially affected on hot days, when almost all showed cyanosis. Such
observations do not state fairly the conditions to-day in view of the
improvements which Grandhomme and Leymann’s observations show have taken
place in aniline factories. Still, cases are fairly frequent. Thus in a
factory with 251 persons employed, thirty-three cases involving 500 days
of sickness were reported.

The Report of the Union of Chemical Industry for 1907 cites the case of a
worker who was tightening up the leaky wooden bung of a vessel containing
aniline at a temperature of 200° C. He was splashed on the face and arms,
and although the burns were not in themselves severe he died the next day
from aniline absorption.

Cases of anilism are not infrequent among dyers. The reports of the
Swiss factory inspectors for 1905 describe a case where a workman worked
for five hours in clothes on to which aniline had spurted when opening
an iron drum. Similar cases are described in the report of the English
factory inspectors for the same year. Aniline black dyeing frequently
gives rise to poisoning, and to this Dearden[9] of Manchester especially
has called attention.

Typical aniline poisoning occurred in Bohemia in 1908 in a cloth presser
working with black dyes. While crushing aniline hydrochloride with
one hand, he ate his food with the other. That the health of persons
employed in aniline black dyeing must be affected by their work is shown
by medical examination. For instance, the English medical inspector of
factories in the summer months of 1905 found among sixty persons employed
in mixing, preparing, and ageing 47 per cent. with greyish coloration of
lips and 57 per cent. characteristically anæmic. Further, of eighty-two
persons employed in padding, washing, and drying, 34 per cent. had grey
lips, 20 per cent. were anæmic, and 14 per cent. with signs of acute or
old effects of chrome ulceration. Gastric symptoms were not infrequently
complained of. The symptoms were worse in hot weather.

Use of aniline in other industries may lead to poisoning. Thus in the
extraction of foreign resins with aniline seventeen workers suffered
(eleven severely). Interesting cases of poisoning in a laundry from use
of a writing ink containing aniline have been recorded.[10]

Reference is necessary to tumours of the bladder observed in aniline
workers. The first observations on the subject were made by Rehn of
Frankfurt, who operated in three cases. Bachfeld of Offenbach noticed in
sixty-three cases of aniline poisoning bladder affections in sixteen.
Seyberth described five cases of tumours of the bladder in workers
with long duration of employment in aniline factories.[11] In the
Höchst factory (and credit is due to the management for the step) every
suspicious case is examined with the cystoscope. In 1904 this firm
collected information from eighteen aniline factories which brought to
light thirty-eight cases, of which eighteen ended fatally. Seventeen were
operated on, and of these eleven were still alive although in three there
had been recurrence.

Tumours were found mostly in persons employed with aniline,
naphthylamine, and their homologues, but seven were in men employed with
benzidine.

Cases of benzene and toluidine poisoning in persons superintending tanks
and stills have been described.

Industrial paranitraniline poisoning has been described, and a fatal case
in the Höchst dye works was attributed by Lewin (as medical referee) to
inhalation of dust. Before his death the workman had been engaged for
five hours in hydro-extracting paranitraniline.

Paraphenylene diamine leads not unfrequently to industrial poisoning
from use of ursol as a dye. It produces skin eruptions and inflammation
of the mucous membrane of the respiratory passages.[12] No doubt the
intermediate body produced (diimine) acts as a powerful poison.

A case of metaphenylene diamine poisoning is quoted in the Report of the
Union of Chemical Industry for 1906. A worker had brought his coffee and
bread, contrary to the rules, into the workroom and hidden them under a
vessel containing the substance. Immediately after drinking his coffee he
was seized with poisoning symptoms, and died a few days later. Some of
the poison must have dropped into his coffee.

Few instances of poisoning from pure aniline colours are recorded.

At first all tar colours were looked upon as poisonous, but as they were
mostly triphenylmethane colours they would contain arsenious acid. When
the arsenic process was given up people fell into the other extreme
of regarding not only the triphenylmethane colours but all others as
non-poisonous, until experience showed that production and use of some of
the tar colours might affect the skin.

Finally, mention must be made of inflammation of the cornea caused by
methyl violet dust. The basic aniline dyes are said to damage the eye.
As opposed to this view is the fact that methyl violet and auramine are
used as anti-bactericidal agents, for treatment of malignant tumours, and
especially in ophthalmic practice.




II. SMELTING OF METALS


LEAD (ZINC, SILVER)

OCCURRENCE OF INDUSTRIAL LEAD POISONING IN GENERAL

_Chronic lead poisoning_ plays the most important rôle in industrial
metallic poisoning, and indeed in industrial poisoning generally. The
result everywhere where inquiry into industrial poisoning has been
instituted has been to place the number of cases of lead poisoning at
the top of the list; for one case of other forms of industrial poisoning
there are twenty of lead.

In the last few years a very extensive literature and one not easily
to be surveyed has grown up on the subject of chronic industrial lead
poisoning. I cannot attempt as I have done with other forms of poisoning
to do justice to all sources of literature on this subject.

As there is no obligation to notify industrial lead poisoning[B]—or
indeed any form of industrial poisoning—in many countries, the most
important source of information is wanting. Nevertheless more or less
comprehensive inquiries as to the extent of the disease in general have
been made in different countries and large cities which furnish valuable
data.

An idea of the yearly number of cases of lead poisoning occurring in
Prussia is given in the following statistics of cases treated in Prussian
hospitals for the years 1895-1901:

    +-------+--------+----------+--------+
    | Year. | Males. | Females. | Total. |
    +-------+--------+----------+--------+
    | 1895  |  1120  |    43    |  1163  |
    | 1899  |  1601  |    23    |  1624  |
    | 1900  |  1509  |    14    |  1523  |
    | 1901  |  1359  |    24    |  1383  |
    +-------+--------+----------+--------+

The occupation of these cases was as follows:

    +-------+----------------+-------------+-----------+
    | Year. | Metallic Lead. | White Lead. | Painters. |
    +-------+----------------+-------------+-----------+
    | 1895  |      364       |    312      |    347    |
    | 1899  |      551       |    310      |    460    |
    | 1900  |      516       |    360      |    378    |
    | 1901  |      498       |    282      |    339    |
    +-------+----------------+-------------+-----------+

About half the cases, therefore, are caused by use of white lead. The
report of the sick insurance societies of the Berlin painters gives
information as to the proportion treated in hospital to those treated at
home, which was as 1:4.

The industries may be classified according to risk as follows[1]:

White lead workers, 33 per cent.; red lead workers, 32 per cent.; shot
and lead pipe workers, 20 per cent.; painters, 7-10 per cent.; lead and
zinc smelters, 8-9 per cent.; printers, 0·5 per cent.

In Austria through the Labour Statistical Bureau comprehensive
information is being collected as to the occurrence of lead poisoning in
the most dangerous trades, but is not yet published. The reports of the
factory inspectors give a very incomplete picture; for example, in 1905
only fifteen cases are referred to. In the most recent report (1909)
information of lead poisoning is only given for thirty works. Teleky
has made a general survey of the occurrence of lead poisoning from the
reports of the Austrian sick insurance societies.[2] From this we gather
that in Vienna, with an average membership of 200,000, there were, in
the five year period 1902-6, 634, 656, 765, 718, 772 cases of illness
involving incapacity from mineral poisons, which Teleky assumes were
practically all cases of lead poisoning. By circularising Austrian sick
insurance societies outside Vienna with a membership of about 400,000,
Teleky obtained information of 189 cases, which he considers too few.

In 1906-1908 inquiry was made by the sick insurance societies in Bohemia
as to the extent of lead poisoning. With an average number employed of
from 700,000 to 850,000 information was obtained of 91, 147, and 132
cases in the three years in question. The increase in 1907 was probably
accounted for by the greater attention paid to the subject.[3] The
number of ascertained cases of lead poisoning treated by the societies
of Hungary was 225 in 1901 and 161 in 1902. Teleky again considers these
figures too low, which is proved by Toth’s publications as to lead
poisoning in Hungarian lead smelting works, and especially Chyzer’s on
lead poisoning among Hungarian potters. Legge has reported fully in
the second International Congress for Industrial Diseases in Brussels
(September 1910) on occurrence of industrial lead poisoning in Great
Britain in the years 1900 to 1909. During that period 6762 cases with 245
deaths occurred. The number of cases in the course of the ten years had
diminished by 50 per cent. These figures appear remarkably small, but
it has to be borne in mind that the statistics referred to related only
to cases occurring in factories and workshops, and do not include cases
among house painters and plumbers. The number of such cases which came to
the knowledge of the Factory Department in 1909 was 241 (with 47 deaths)
and 239 in 1908 (with 44 deaths).


LEAD, SILVER, AND ZINC SMELTING

_Lead_ is obtained almost entirely from galena by three different
processes. In the _roast and reaction process_ galena is first roasted at
500°-600° C. and partially converted into lead oxide and lead sulphate:
on shutting off the air supply and increase of temperature the sulphur
of the undecomposed galena unites with the oxygen of the lead oxide
and sulphate to form sulphur dioxide, while the reduced metallic lead
is tapped. In the _roast and reduction_ process the ore is completely
calcined so as to get rid of sulphur, arsenic, and antimony. The oxides
(and sulphates) formed are reduced by means of coke in a blast furnace.
This process is generally applicable and is, therefore, that most in use.
The _precipitation_ process consists chiefly in melting galena with coke
and iron flux, whereby the lead is partly freed from the sulphur, and, in
addition to lead, iron sulphide is formed, which acts on the remaining
lead sulphide, producing a lead matte which can be further treated.

[Illustration: FIG. 27.—Smelting Furnace, showing mechanical charging
and exhaust ventilation applied to slag runs, &c. (_Locke, Lancaster &
W. W. & R. Johnson & Sons, Ltd. By permission of the Controller of H.M.
Stationery Office._)]

The roast and reaction process is carried out in specially constructed
reverberatory furnaces; small furnaces with small amounts of ore and at
as low a temperature as possible are the rule in the Kärntner process.
In the English process large amounts of ore are melted in large furnaces
at high temperatures so as to oxidise the material. The so-called
Tarnowitz process combines these two—large amounts of ore are roasted
in large furnaces at a moderate temperature. In the roast and reduction
process it depends on the nature of the ore whether the roasting is done
in reverberatory or blast furnaces. Generally the ore is in the form
of powder—less often in pieces. Pyritic ore (ore with much sulphur) is
almost always roasted in blast furnaces, and the sulphur dioxide evolved
can be used in the manufacture of sulphuric acid. Open-hearth furnaces
are rarely used now. Reverberatory furnaces are employed most frequently.

The lead thus obtained contains several other metals, especially silver,
copper, arsenic, antimony, iron, zinc, bismuth, and tin. Lead containing
silver (work-lead) is next _de-silverised_, after which follows refining
to get rid of the other impurities. For de-silverising work-lead rich
in silver (containing about 10 per cent.) _cupellation_ is practised,
in which the silver lead is melted and oxidised so that the lead is
converted into _litharge_, metallic silver remaining behind. In a
cupellation furnace the flame strikes on the top of the lead bath, and
at the same time air under slight pressure is driven in; the litharge
which forms is removed through suitable openings. The litharge that is
first formed contains silver and is treated again; the remainder is ready
for market. After the litharge has run off silver appears, containing
still 5-10 per cent. of lead, and it is again submitted to an analogous
refining process. Work-lead which does not contain enough silver to be
cupelled at once is generally treated first by either the Pattinson or
the Parkes’ process.

In the _Pattinson_ crystallising process work-lead is melted in open
semi-circular pots: as the pots cool crystals of lead poor in silver form
on the surface and are transferred by a perforated ladle into the next
pot: the silver collects in the small amount of molten lead remaining
behind. Lead that has become enriched by repeated crystallisation
contains a high percentage of silver and is cupelled. The _Parkes’_
process or _zinc de-silverisation_ depends on the formation of a
lead-zinc alloy which is less fusible than lead. Work-lead is melted
and agitated with addition of pure zinc. The crust which first rises on
cooling contains gold, copper, zinc, and lead, and is removed. Further
addition of zinc is then made: the rich silver crust which separates
is subsequently freed from lead by gradual heating in a reverberatory
furnace, and from zinc, in a zinc distilling retort. Other impurities
are got rid of by oxidising in reverberatory or other furnaces. Small
quantities of antimony and arsenic are removed by stirring with fresh
green sticks.

_Zinc_ is obtained principally from blende (sulphide of zinc) and from
calamine (carbonate of zinc). The process of zinc recovery depends on the
production of zinc oxide and reduction of this by carbon to metallic zinc.

Conversion of the ore to zinc oxide is effected by roasting. Since
the temperature at which reduction takes place is higher than the
melting-point of zinc the latter is volatilised (distilled) and must be
condensed in suitable condensers.

Calamine is calcined in a blast furnace. Blende was formerly roasted in
reverberatory furnaces, but such nuisance arose to the neighbourhood from
sulphur dioxide vapour that now Hasenclever-Helbig calcining furnaces
are used. These furnaces furnish a gas so rich in sulphur dioxide that
they serve at once for the production of sulphuric acid. The Hasenclever
furnaces consist of muffles placed one above another: the finely ground
ore is charged through hoppers above and then raked down from muffle to
muffle.

Reduction is carried out in the Belgian or Silesian process by strongly
heating calcined matte with coal in retorts. The zinc as it distils is
caught in special condensing receptacles (prolongs). After distillation
is complete the residue is raked out of the muffle and the furnace
charged afresh. As zinc ores generally contain much lead, the work-zinc
is therefore refined by remelting in a reverberatory furnace, during
which process the impurities collect on the zinc as dross and are removed
by agitation with sal-ammoniac or magnesium chloride.

[Illustration: FIG. 28.—Arrangement of Spelter Furnace showing
Ventilating Hood.]

RISK OF POISONING IN LEAD, SILVER, AND ZINC SMELTING.—As the description
of the manipulations in smelting processes shows, all involve risk of
lead poisoning. As a matter of fact in lead smelting much lead passes
into the atmosphere. In the smelting works at Tarnowitz yearly some
36,000 kilos of oxidised lead escape.

Estimations[4] of the amount of lead in air samples collected in lead
smelting works have been made. Thus in a cubic metre of air immediately
over the slag run from 0·0029 to 0·0056 g. of lead were found, so
that a worker in a ten-hour day would inhale from 0·013 to 0·025 g. of
lead. In a cubic metre of air immediately above the Parkes’ melting-pot
from 0·0056 to 0·0090 g. were found, so that a worker would inhale
daily from 0·0252 to 0·0405 g. if he kept constantly close to the pot.
On the handles of a de-silveriser 0·112 g. were found. In Hungarian
lead-smelting works the water in which the hands had been washed was
found to contain 1·27 g. of lead per litre. The hands of litharge
grinders and sifters showed the highest amounts.

Work carried on in lead-smelting works may be divided into five classes
according to risk. Those most exposed to risk are the smelters at lead
hearths and reverberatory furnaces, persons employed at the lead and
slag runs, flue cleaners, and in crushing and packing flake litharge.
Next come those employed at the refining furnaces, those breaking up the
roasted ore, blast furnace workers, and those employed at the cupellation
process. Attended with danger also is the removal of lead ashes and
distillation of the zinc crust. Less dangerous are transport of material,
crushing and mixing the ore, refining the work-lead and zinc crust, and
work at the Pattinson and Parkes’ processes.

In zinc smelting risk of lead poisoning is great, no matter which process
is in question, because of the high proportion of lead in the ore and
work-zinc. Swedish blende contains as much as 9 per cent. of lead, and
Upper Silesian 2½ per cent. or less. There is risk in calcination, but it
is much less than in the distillation process.[5]

There are no quite satisfactory statistics as to the number of cases
of lead poisoning in smelting works. Nevertheless, a number of recent
publications give valuable data for certain smelting works in Germany,
Austria, and Hungary.

From details[6] of lead poisoning at Tarnowitz it would appear that the
conditions have materially improved since 1884, the cases having declined
from 32·7 per 100 employed in 1884 to 6·2 in 1894 and 1895. The following
figures show the proportion affected in the different processes in the
years 1901 and 1902:

    Process.                 Year.  No. Employed.  Cases.   Per Cent.

    Reverberatory Furnace {  1901   131            11       8·3
                          {  1902   111             4       3·6
    Blast Furnace         {  1901   152            47      30·9
                          {  1902   187            21      11·1
    Cupelling Furnace     {  1901    12             1       8·3
                          {  1902    12             1       8·3
    De-silverising        {  1901    32            10      31·2
                          {  1902    34             7      20·6
    Other Employment      {  1901   300             7       2·3
                          {  1902   350             2       0·6

In one smelting works the percentage attack rate was 17·8 in 1901, and
27·1 in 1902. Here the number of workers had increased from 73 in 1901 to
129 in 1902, and the absolute and relative increase probably has relation
to the well-known fact that newly employed untrained workers become
affected. Similar incidence according to process can be given for the
Friedrich’s smelting works during the years 1903-1905:

    Process.              Year.    No. Employed. Cases. Per Cent.

    Reverberatory Furnace { 1903       86          12     13·9
                          { 1904       87           8      9·2
                          { 1905       83          11     13·3
    Blast Furnace         { 1903      267          59     22·1
                          { 1904      232          24     10·3
                          { 1905      247          27     10·9
    De-silverising        { 1903       56          12     21·4
                          { 1904       73           4      5·5
                          { 1905       75           4      5·3
    Cupelling             { 1903       16           4     25·0
                          { 1904       15           1      6·7
                          { 1905       14           1      7·1
    Other Employment      { 1903      330           5      1·5
                          { 1904      309           4      1·3
                          { 1905      347           7      2·0

Among 3028 cases of lead poisoning treated between 1853 and 1882 in
smelting works near Freiberg (Saxony) gastric symptoms were present in
1541, rheumatic pains in 215, cerebral symptoms in 144, paralysis in 58,
and lead colic in 426.

The recent reports of the German factory inspectors point still to rather
high incidence in many lead smelting works. Thus in the district of Aix
la Chapelle in 1909 there were sixty cases involving 1047 sick days, as
compared with 58 and 878 in 1908.

In a well-arranged smelting works near Wiesbaden fifty-two and forty-two
cases were reported in 1908 and 1909 respectively, among about 400
persons employed. This relatively high number was believed to be closely
connected with frequent change in the _personnel_. Introduction of the
Huntingdon-Heberlein method is thought to have exercised an unfavourable
influence.

Other smelting works in Germany appear to have a relatively small number
of reported cases. Thus in 1909 among 550 workers employed in four
smelting works in the Hildesheim district only four cases were reported,
and in the district of Potsdam among 600 smelters only five were found
affected on medical examination. There is no doubt that many of the cases
described as gastric catarrh are attributable to lead. Full information
as to the conditions in Austria is contained in the publication of the
Imperial Labour Statistical Bureau. In this comprehensive work the
conditions in smelting works are described. In the lead smelting works
at Przibram the cases had dropped from an average of 38·2 among the
4000-5000 persons employed to twenty-two in 1894 and to six in 1903, but
only the severer cases are included. No single case has occurred among
the 350-450 persons engaged in mining the ore, as galena (lead sulphide)
is practically non-poisonous. It was found, for example, that 50 per
cent. of the furnace men had (according to their statement) suffered from
lead colic. Of eight employed in the Pattinson process, seven stated they
had suffered from colic. The lead smelting works in Gailitz showed marked
frequency of lead poisoning—here the appointed surgeon attributed anæmia
and gastric and intestinal catarrh to lead:

                             Illness of Saturnine Origin.
    Year. No.      Lead Colic.                                  Per Cent.
          Employed.      Anæmia.     Intestinal Catarrh.          due to
                              Gastric        Total Lead   Total     Lead.
                              Catarrh.        Sickness.  Sickness.
    1899    61       14    2    76     16        108      178       60·0
    1900    57        6    2    16      5         29       80       36·2
    1901    48        4    2    17      1         24       60       40·0
    1902    47        —    —    24      6         30       56       53·5
    1903    49        —    3    11      4         18       57       31·6

The diminution in the number of cases, especially of colic, is
attributable to the efforts of the appointed surgeon.

At Selmeczbanya a diminution from 196 cases in 1899 (50·7 per cent.) to
six (2·2 per cent.) in 1905 had taken place. These figures point clearly
to the success of the hygienic measures adopted in the last few years.

In the large spelter works of Upper Silesia during the years 1896-1901,
among 3780 persons employed, there were eighty-three cases of lead colic
and paralysis, that is, about 2·2 per cent. each year. The following
tables show the incidence among spelter workers in the works in question
from 1902 to 1905:

    ILLNESS AMONG ZINC SMELTERS

            Lead Colic
    Year.     and          Kidney   Gastric  Anæmia. Rheumatism.    No.
          Lead Paralysis.  Disease. Catarrh.                     Employed.

    1902       29            18        137      18      448         4417
    1903       28            21        151      24      470         4578
    1904       44            23        181      35      596         4677
    1905       50            18        223      40      612         4789

    Average   0·8%          0·5%       3·7%    0·6%     11·5%       4615

    ILLNESS AMONG CALCINERS

            Lead Colic
    Year.     and          Kidney   Gastric  Anæmia. Rheumatism.    No.
          Lead Paralysis.  Disease. Catarrh.                     Employed.

    1902        —             —          5       1       78         1149
    1903        —             —          9       —      112         1087
    1904        2             —         68       1      136         1140
    1905        1             2         47       2      134         1159

    Average  0·08%         0·05%      2·6%     0·1%     10·2%       1134

In thirty-two spelter works in the district of Oppeln in the year 1905,
among 4789 spelter workers proper, there were 50 cases of colic, 18 of
kidney disease, 223 of gastric and intestinal catarrh, 40 of anæmia, and
612 of rheumatism, and among 1159 calciners 1 case of colic, 2 of kidney
disease, 47 of gastric catarrh, 2 of anæmia, and 134 of rheumatism. Cases
are much more numerous in spelter works where Swedish blende containing
lead is worked. It is remarkable, however, that in large spelter works in
Upper Silesia, where for years no cases of lead poisoning were reported,
medical examination showed that 20·5 per cent. had signs of lead
absorption.


White Lead and Lead Colours

MANUFACTURE.—The primitive Dutch process consisted in placing lead grids
in earthenware pots containing dilute acetic acid and covering them
with tan bark. Fermentation ensued with evolution of carbonic acid gas
and increase in temperature. The acetic acid vapour forms, with aid of
atmospheric oxygen, first basic lead acetate, which, by the action of
the carbonic acid gas, becomes converted into white lead and neutral
lead acetate. The product is crushed, sieved, and dried. In the German
or Austrian process thin sheets of metallic lead are hung saddle-wise
in chambers. Acetic acid vapour and carbonic acid gas (produced by
burning coke) are led in from below. The chamber is then sealed and kept
so for a considerable time. When the chamber is ‘ripe’ the white lead
that has formed is taken out, freed from uncorroded lead by spraying,
dried, finely ground, and packed. White lead comes on the market either
as a powder or incorporated with oil. Of the remaining lead colours,
red lead (Pb₃O₄) is much used. It is produced by heating lead oxide in
reverberatory furnaces with access of air and stirring.


Lead Poisoning in the Manufacture of White Lead and Lead Colours

The manufacture by the German process may be divided into three
categories according to the degree of risk run:

1. The most dangerous processes are hanging the plates in the chambers,
work at the filter press, drying, pulverising, and packing by hand.

2. Less dangerous are transport to the washer, washing, and grinding.

3. Relatively the least dangerous are casting the plates, transport of
them to the chambers, drying, mechanical packing, and mixing with oil.

The number of cases of lead poisoning in white lead factories is often
relatively great despite regulations. Casual labourers especially run
the greatest risk. This is frequently brought out in the reports of the
German factory inspectors, who connect the high proportion of cases
directly with the large number of unskilled workers. Regulations are
really only successful in factories with regular employment.

This has been found also in Great Britain, where the Medical Inspector
of Factories showed that the cases among regular workers numbered 6 per
cent. and among casual workers 39 per cent.

The following table gives particulars as to the occurrence of lead
poisoning in the white lead factories in the district of Cologne in 1904,
some of which have admirable hygienic arrangements:

  +-----------+--------------+-----------------+---------------+--------+
  |           |              | No. Employed.   |Cases of Lead  |        |
  |           |              |                 |Poisoning.     |        |
  |           |              +-----------------+---------------+ No. of |
  |  Place.   | Manufacture. |Regular          |Regular        |Cases of|
  |           |              |     |Casual     |    |Casual    |Gastric |
  |           |              |     |     |Average   |    |Total|Catarrh.|
  +-----------+--------------+-----+-----+-----+----+----+-----+--------+
  |Cologne I. | White lead  {|  46 |  59 |  32 |  9 | 16 |  25 |   16   |
  |           |             {| 173 |  95 | 127 | 13 | 17 |  30 |   22   |
  |   ”    I. | Litharge and{|  46 |   4 |  38 |  5 |  1 |   6 |    7   |
  |           | red lead    {|  76 |  62 |  49 |  3 |  4 |   7 |   15   |
  |           | Chromate    {|  14 |   2 |  11 |  — |  — |   — |    5   |
  |           |             {|  43 |  72 |  33 |  — |  — |   — |    7   |
  |Cologne II.| White lead, {|     |     |     |    |    |     |        |
  |           | litharge,   {| 107 | 332 |  91 |  6 | 34 |  40 |   30   |
  |           | and red lead{| 102 | 332 |  76 |  9 | 19 |  28 |   38   |
  +-----------+--------------+-----+-----+-----+----+----+-----+--------+

It is worth noting that cases of lead poisoning have been reported in the
manufacture of zinc white, as, for example, in Bohemia in 1907 and 1908.


USE OF LEAD COLOURS AND PAINTS (HOUSE PAINTERS, DECORATORS, ETC.)

Use of lead colours, especially by painters and decorators, causes
relatively much lead poisoning. Apart from ignorance of danger on
the part of the worker, and lack of personal cleanliness, unsuitable
methods of working add to the danger, especially dry rubbing of painted
surfaces, which gives rise to much dust containing lead. Again, the
crushing and mixing of lumps of white lead and rubbing lead colours with
the hand are very dangerous.

The following German and Austrian figures enable conclusions to be
drawn as to the frequency of lead poisoning among painters. In the sick
insurance societies of Frankfurt-a-M. in 1903 of every 100 painters 11·6
suffered from an attack of lead poisoning. The similar sick insurance
society of painters in Berlin has kept useful statistics which are given
in the following table for the ten years 1900-9:

    +--------+----------+------------+--------------+
    |        |          |   No.      |              |
    |        | No. of   | of Cases   |  Cases per   |
    | Year.  | Members. | of Lead    | 100 Members. |
    |        |          | Poisoning. |              |
    +--------+----------+------------+--------------+
    | 1900   |   3889   |    357     |     9·18     |
    | 1901   |   3616   |    335     |     9·26     |
    | 1902   |   3815   |    308     |     8·07     |
    | 1903   |   4397   |    470     |    10·69     |
    | 1904   |   5029   |    516     |    10·26     |
    | 1905   |   5328   |    471     |     8·84     |
    | 1906   |   5355   |    347     |     6·48     |
    | 1907   |   5173   |    379     |     7·32     |
    | 1908   |   4992   |    298     |     5·97     |
    | 1909   |   4781   |    285     |     5·96     |
    +--------+----------+------------+--------------+
    |Average |   4637   |    376·6   |     8·11     |
    +--------+----------+------------+--------------+

This shows that lead poisoning among the painters of Berlin is happily
diminishing, which may be attributed to recent regulations. The society,
however, complains in its reports that not all cases of lead appear
as such in their statistics, and believes that all diseases entered
as rheumatism, gastric catarrh, nervous complaints, heart and kidney
disease, should be regarded as associated with lead. The kinds of work in
which painters suffer most are painting iron girders and machines, sheet
metal and iron furniture, railway waggons, agricultural implements, coach
painting, cabinet-making, shipbuilding, and the use of red and white
lead. The use of lead colours, _lead acetate_, and _lead chromate_ often
give rise to lead poisoning. Colours containing lead are not infrequently
used in the textile industry in dyeing, printing, and finishing. White
lead has been used for weighting the weft.

Teleky has described cases of lead poisoning in which _silk thread_ was
weighted with acetate of lead. As a consequence a number of women engaged
in sewing on fringes with the thread suffered. The English factory
inspectors’ reports describe cases from manipulating _yarn dyed with
chromate of lead_.[7]

_Chromate of lead_ and _white lead_ are used in colouring oil-cloth,
artificial flowers, paper, rubber goods, pencils, penholders, socks,
sealing-wax, candles, and stamps.


USE OF LEAD IN THE CHEMICAL INDUSTRY

Lead poisoning has been frequently observed in such branches of the
chemical industry as require large leaden or lead-lined vessels and
pipes: the persons affected are principally those engaged in lead burning.

Risk is considerable in manufacture of lead acetate. The most dangerous
processes are drying and packing the crystals.


MANUFACTURE OF ELECTRIC ACCUMULATORS

The manufacture of accumulators begins with the casting of lead plates,
which are then polished and dressed. Next follows ‘pasting,’ that is,
smearing the negative plate with a paste of litharge, the positive plate
being ‘formed’ by having an electric current passed through so that the
lead is converted into spongy peroxide. The wooden boxes in which the
plates are assembled are lead-lined.

The most dangerous processes are casting, wire-brushing, and pasting—the
latter especially when done by hand.

In the years 1908 and 1909 among about 761 workers employed in the
accumulator factories of Cologne there were fifty-six cases of lead colic
and seventy-nine of gastric and intestinal catarrh. Further figures
for German accumulator works show that in the two largest accumulator
factories in the district of Potsdam employing 142 workers there were
fifteen cases in 1904. In Great Britain, in the ten years 1900-1909, 285
cases were reported—an average of about thirty a year.


THE CERAMIC INDUSTRY

Risk is present in several branches of the ceramic industry. It is
greatest in glazing earthenware, but not infrequent also in the porcelain
and glass industries. It is impossible to deal with the extensive
literature on this subject exhaustively. A comprehensive and detailed
survey of lead poisoning in the ceramic industry on the Continent is
that by Kaup. Distinction is made between leadless glazes which melt
at high temperature and lead glazes which have the advantage of a low
melting-point. Galena and litharge are used in the preparation of glazes
for common earthenware and red and white lead for ware of better quality.
Distinction has to be made between a lead silicious glaze for pottery
ware, a lead and boric acid glaze for stoneware, and a lead and zinc
oxide glaze for ordinary faience and stoneware. Seegar, the celebrated
expert, praises the advantage of lead glaze and the use of lead in the
ceramic industry—it is indeed practically indispensable—and speaks of the
poisonous nature of lead as its only fault. The components of the glaze
must have definite relation to the hardness or softness of the body. The
higher the proportion of silicic acid in the glaze the harder the firing
it will stand; the more the flux materials are in excess the lower will
the melting point be.

The most important flux materials are, arranged in order of decreasing
fusibility, lead oxide, baryta, potash, soda, zinc oxide, chalk,
magnesia, and clay.

The _glaze_ is made by first mixing the ingredients dry, and then
either fritting them by fluxing in a reverberatory furnace and finally
grinding them very finely in water or using the raw material direct. In
the fritting process in the case of the lead glazes the soluble lead
compounds become converted into less soluble lead silicates and double
silicates.

The glaze is applied in different ways—dipping, pouring, dusting,
blowing, and volatilising. Air-dried and biscuited objects are dipped;
pouring the glaze on is practised in coarse ware, roofing-tiles, &c.;
dusting (with dry finely ground glaze, litharge, or red lead) also in
common ware; glaze-blowing (aerographing) and glaze dusting on porcelain.
In these processes machines can be used. Bricks are only occasionally
glazed with glazes of felspar, kaolin, and quartz, to which lead oxide
is often added in very large quantity. Lead poisoning in _brick works_
in view of the infrequent use of lead is not common, but when lead is
used cases are frequent. Kaup quotes several cases from the factory
inspectors’ reports: thus in three roof-tiling works examination by the
district physician showed that almost all the workers were affected.

_Coarse ware pottery_ is made of pervious non-transparent clay with
earthy fracture—only a portion of this class of ware (stoneware) is
made of raw materials which fire white. Such ware generally receives a
colourless glaze. The clay is shaped on the potter’s wheel, and is then
fired once or, in the better qualities, twice.

Grinding the ingredients of the glaze is still often done in primitive
fashion in mortars. The glaze is usually composed of lead oxide and
sand, often with addition of other lead compounds as, for example, in
quite common ware, of equal parts of litharge, clay, and coarse sand.
Sometimes, instead of litharge, galena (lead sulphide) or, with better
qualities of ware, red lead or ‘lead ashes’ are used.

The grinding of the glazes in open mills or even in mortars constitutes a
great danger which can be prevented almost entirely by grinding in ball
mills. The glaze material is next mixed with water, and the articles are
either dipped into the creamy mass or this is poured over them. In doing
this the hands, clothes, and floors are splashed. The more dangerous
dusting-on of glaze is rarely practised. Occasionally mechanical
appliances take the place of hand dipping. Placing the ware in the glost
oven is done without placing it first in saggars.

In the better qualities of pottery cooking utensils, which are fired
twice, a less fusible fritted lead glaze is generally used. Coloured
glaze contains, besides the colouring metallic oxides, 30-40 per cent. of
litharge or red lead.

As Kaup shows, Continental factory inspectors’ reports make only isolated
references to occurrence of lead poisoning in potteries. Insight into the
conditions in small potteries is obtained only from the Bavarian reports.
In Upper Bavaria ninety-three potteries employ 157 persons who come into
contact with lead glaze. Eleven cases were known to have occurred in the
last four years. Teleky found thirty-six cases of lead poisoning (mostly
among glostplacers) in the records of the Potters’ Sick Insurance Society
of Vienna.

Chyzer has described the striking conditions in Hungary. There there
are about 4000 potters, of whom 500 come into contact with lead glaze.
Chronic lead poisoning is rife among those carrying on the occupation as
a home industry. Members of the family contract the disease from the dust
in the living rooms. This dust was found to contain from 0·5 to 8·7 per
cent. of lead.

In the china and earthenware factories in Great Britain, in the ten years
1900-9, 1065 cases with fifty-seven deaths were reported.

_Manufacture of stove tiles._—The application of glaze to stove tiles is
done in different ways. The two most important kinds are (1) fired tiles
and (2) slipped tiles. In the production of fired tiles a lead-tin alloy
consisting of 100 parts lead and 30-36 parts tin—so-called ‘calcine’—are
melted together in fireclay reverberatory or muffle furnaces and raked
about when at a dull red heat so as to effect complete oxidation. The
material when cool is mixed with the same quantity of sand and some
salt, melted in the frit kiln, subsequently crushed, ground, mixed with
water, and applied to the previously fired tiles. In this process risk
is considerable. Presence of lead in the air has been demonstrated even
in well-appointed ‘calcine’ rooms. In unsuitably arranged rooms it was
estimated that in a twelve-hour day a worker would inhale 0·6 gramme of
lead oxide and that 3-8 grammes would collect on the clothes.

_Slipped tiles_ are made in Meissen, Silesia, Bavaria, and Austria by
first applying to them a mixture of clay and china clay. The glaze
applied is very rich in lead, containing 50-60 parts of red lead or
litharge. Generally the glaze is applied direct to the unfired tiles
and fired once. Figures as to occurrence of poisoning in Germany are
quoted by Kaup from the towns of Velten and Meissen. Among from 1748 to
2500 persons employed thirty-four cases were reported in the five years
1901-5. Thirteen cases were reported as occurring in the three largest
factories in Meissen in 1906.

From other districts similar occurrence of poisoning is reported. In
Bohemia in a single factory in 1906 there were fourteen cases with one
death, in another in 1907 there were fourteen, and in 1908 twelve cases;
eight further cases occurred among majolica painters in 1908.

_Stoneware and porcelain._—Hard stoneware on a base of clay, limestone,
and felspar has usually a transparent lead glaze of double earth
silicates of lead and alkalis, with generally boric acid to lower the
fusing-point; the lead is nearly always added in the form of red lead
or litharge. The portion of the glaze soluble in water is fritted, and
forms, when mixed with the insoluble portion, the glaze ready for use.
The frit according to Kaup contains from 16 to 18 per cent. of red lead,
and the added material (the mill mixing) 8-26 parts of white lead; the
glaze contains from 13 to 28 parts of lead oxide. The ware is dipped or
the glaze is sometimes aerographed on. Ware-cleaning by hand (smoothing
or levelling the surface with brushes, knives, &c.) is very dangerous
work unless carried out under an efficient exhaust. Colouring the body
itself is done with coloured metal oxides or by applying clay (slipping)
or by the direct application of colours either under or over the glaze.
Some of the under-glaze colours (by addition of chrome yellow or nitrate
of lead or red lead) contain lead and are applied with the brush or
aerograph or in the form of transfers.

_Plain earthenware_ is either not glazed or salt glazed; only when
decorated does it sometimes receive an acid lead glaze.

_Porcelain_ receives a leadless glaze of difficultly fusible silicate
(quartz sand, china clay, felspar). Risk is here confined to painting
with lead fluxes (enamel colours) containing lead. These fluxes are
readily fusible glasses made of silicic acid, boric acid, lead oxide, and
alkalis, and contain much lead (60-80 per cent. of red lead).

In the _glass industry_ lead poisoning may occur from use of red lead as
one of the essential ingredients. In Great Britain, in the years 1900-9,
forty-eight cases were reported in glass polishing from use of putty
powder.


LETTERPRESS PRINTING, ETC.

Type metal consists of about 67 per cent. lead, 27 per cent. antimony,
and 6 per cent. tin, but sometimes of 75 per cent. lead, 23 per cent.
antimony, and 2 per cent. tin.

The actual printer comes least of all in contact with lead. Use of lead
colours (white lead, chromate of lead, &c.) may be a source of danger,
especially in the preparation of printing inks from them and in cleaning
the printing rolls. A further, if slight, danger arises from the use of
bronze powder consisting of copper, zinc, and tin. The two last-named
metals contain from 0·1 to 0·5 per cent. of lead, and in the application
and brushing off of the bronze there is a slight risk.

The compositor is exposed to constant danger from handling the type and
disturbing the dust in the cases. This dust may contain from 15 to 38
per cent. of lead. Blowing the dust out of the cases with bellows is
especially dangerous, and want of cleanliness (eating and smoking in the
workroom) contributes to the risk.

Type founders and persons engaged in rubbing and preparing the type
suffer. Introduction of type-casting machines (linotype, monotype) has
lessened the danger considerably.

No lead fumes are developed, as a temperature sufficiently high to
produce them is never reached. In all the processes, therefore, it is
lead dust which has to be considered.

The following figures of the Imperial Statistical Office as to occurrence
of lead poisoning among printers in Vienna indicate the relative danger:

    +---------------------------+-----------+-----------+----------+
    |Occupation.                |Average No.|Average No.|Percentage|
    |                           |of Members,| of Cases, | of Cases,|
    |                           |1901-1906. |1901-1906. |1901-1906.|
    +---------------------------+-----------+-----------+----------+
    |Compositors                |    3182   |   90·3    |   2·8    |
    |Printers                   |     809   |   20·3    |   2·4    |
    |Casters and Stereotypers   |     241   |   15·8    |   6·6    |
    |Females employed in casting|      74   |   8·17    |  10·8    |
    +---------------------------+-----------+-----------+----------+

In Bohemia there is reference to thirty-eight cases in letterpress
printing in 1907 and twenty-seven in 1908.

Among 5693 persons treated for lead poisoning between the years 1898 and
1901 in hospitals in Prussia, 222 were letterpress printers.

Between 1900 and 1909 in Great Britain 200 cases of lead poisoning were
reported.


VARIOUS BRANCHES OF INDUSTRY

The number of industries using lead is very large. Layet as long ago as
1876 enumerated 111. We, however, limit ourselves to those in which the
risk is considerable.

Use of _lead beds_ in _file-cutting_ has given rise to many cases.
Further, to harden the file it is dipped into a bath of molten lead.
From 3 to 6 per cent. of lead has been found in the dust in rooms where
hardening is done.

Of 7000 persons employed in file-cutting in the German Empire in the
years 1901-5 on an average 30·5 or 0·43 per cent. were affected yearly.
In Great Britain 211 cases were reported in the years 1900-9.

In _polishing precious stones_ formerly many cases of lead poisoning
occurred, the reason being that the polishers come into contact with
particles of lead and fix the diamonds to be polished in a vice composed
of an alloy of lead and tin. Danger is increased when the stones are
actually polished on revolving leaden discs. In Bohemia granite polishing
used to be done in this way, but is now replaced in many factories by
carborundum (silicon carbide).

Musical instrument making in Bohemia in the years 1906-8 was found
regularly to give rise to cases of lead poisoning from use of molten lead
in filling them with a view to shaping and bending. In lead pipe and
organ pipe works, lead burning, plumbing, &c., considerable risk is run.

Often the causes of lead poisoning are difficult to discover, and, when
found, surprising. Thus shoemakers have suffered from holding leaden
nails in the mouth. Again, cases in women have been reported from cutting
out artificial flowers or paper articles with aid of lead patterns, or
counting stamps printed in lead colours.[8]


MERCURY

As metallic mercury gives off vapour even at ordinary temperatures,
poisoning can occur not only in the recovery of the metal from the ore,
but also in all processes in which it is used.

Chronic industrial poisoning occurs principally in the preparation and
use of mercury salts, in recovery of the metal itself and of other metals
with use of an amalgam, in water gilding, from use of nitrate of mercury
in the preparation of rabbit fur for felt hat making, from use of mercury
pumps in producing the vacuum in electric filament lamps, and in making
barometers and thermometers.

PREPARATION.—Mercury is obtained by roasting cinnabar (sulphide of
mercury). When cinnabar is heated with access of air the sulphide burns
to sulphur dioxide and the mercury volatilises and is subsequently
condensed. Formerly the process was carried on in open hearths; now it
is done usually in blast furnaces. The mercury is condensed in Idria
in large chambers cooled with water, while at Almaden in Spain it is
collected in a series of small earthenware receptacles (aludels), from
small openings in which the mercury flows in gutters and collects. The
mercury so recovered is usually redistilled.

On the walls of the condensers a deposit of sulphide and oxide of mercury
collects, removal of which is one of the operations most attended with
risk.

Recovery of silver or gold by amalgamation with mercury is carried on
only in America. The metallic silver or gold is taken up by the mercury,
from which it is recovered by distillation.

The conditions in the quicksilver mines of Idria in Austria have improved
of late years. Thus in the five years prior to 1886 of 500 cases of
illness more than 11 per cent. were due to chronic mercurial poisoning.
In 1906, 209 persons were employed, of whom only one-third were permanent
hands. Among these the sickness rate was very high (95-104 per cent.).
Of 741 cases of illness among the miners there were six of mercury
poisoning, and of 179 among persons employed in recovery of the metal,
twelve cases.[1]

The conditions of employment in the cinnabar mines of Monte Amiata in
Italy have recently been described in detail.[2] Here, although the
recovery of the metal is carried out in modern furnaces, thus greatly
reducing the danger, nevertheless nearly all the furnace workers suffer
from chronic poisoning.

In _silvering of mirrors_ the leaf of tinfoil was spread out on an
inclined table; mercury was poured over it and the sheet of glass laid
on the top with weights. The superfluous mercury was squeezed out and
ran away owing to the sloping position of the table. Now this process,
even in Fürth, is almost entirely replaced by the nitrate of silver and
ammonia process. Years ago the number of cases of poisoning was very
serious in places where, as in Fürth, the work was carried on as a home
industry.

In the production of _incandescent electric bulbs_ danger arises from
breaking of the glass pipes of the pumps and scattering of mercury on
the floor of the workrooms. Since there is a growing tendency to replace
mercury pumps by air pumps such cases ought to become rare.

In _water gilding_—a process little employed now—the metal objects
(military buttons, &c.) to be gilded, after treatment with a flux, are
brushed over with the mercury amalgam, and subsequently fired to drive
off the mercury. Unless careful provision is made to carry away the
vapour chronic poisoning cannot fail to occur. Even sweeps have been
affected after cleaning the chimneys of water gilders’ workshops. In
Great Britain, between 1899 and 1905, six cases were reported among water
gilders.

In the _manufacture of barometers_ and thermometers mercury poisoning is
not infrequent. Between 1899 and 1905 sixteen such cases were reported in
England; during the same period there were seventeen cases among those
putting together electrical meters.

Risk of mercurial poisoning is constantly present in _hatters’ furriers’
processes_ and in subsequent processes in felt hat factories. The risk
from use of nitrate of mercury is considerable to those brushing the
rabbit skins with the solution (carotting), and subsequently drying,
brushing, cutting, locking, and packing them. According to Hencke in
100 kilos of the carotting liquid there are 20 kilos of mercury. In
England, in the years 1899-1905, thirteen cases of mercurial poisoning
were reported in hatters’ furriers’ processes. Among eighty-one persons
so employed the medical inspector found twenty-seven with very defective
teeth as the result of the employment, and seventeen with marked tremor.

In the _manufacture of mercurial salts_ poisoning occurs chiefly when
they are made by sublimation, as in the manufacture of vermilion, of
corrosive sublimate (when mercurous sulphate is sublimed with salt), and
in the preparation of calomel (when sublimate ground with mercury or
mercurous sulphate mixed with mercury and salt is sublimed). Between 1899
and 1905 in England seven cases were reported from chemical works. As
to occurrence of mercury poisoning from _fulminate of mercury_, see the
chapter on Explosives.


ARSENIC

Chronic industrial _arsenical poisoning_, both as to origin and course,
is markedly different from the acute form.

The chronic form arises mainly from inhalation of minute quantities of
metallic arsenic or its compounds in recovery from the ore, or from the
use of arsenic compounds in the manufacture of colours, in tanyards, and
in glass making. Acute industrial _arseniuretted hydrogen poisoning_ is
especially likely to occur where metals and acids react on one another
and either the metal or the acid contains arsenic in appreciable amount.
Further, arseniuretted hydrogen may be contained in gases given off in
smelting operations and in chemical processes.

RECOVERY OF ARSENIC AND WHITE ARSENIC.—Pure arsenic is obtained from
native cobalt and arsenical pyrites by volatilisation on roasting the
ore in the absence of air. After the furnace has been charged sheet iron
condensing tubes are affixed to the mouths of the retorts, which project
out of the furnace, and to these again iron or earthenware prolongs.
Arsenic condenses on the sides of the sheet metal tubes and amorphous
arsenic, oxides, and sulphides in the prolongs. After sublimation has
been completed the contents of the prolongs are removed and used for
production of other arsenic compounds; the (generally) argentiferous
residues in the retorts are removed and further treated in silver
smelting works; finally, the crusts of crystalline arsenic (artificial
fly powder) are knocked out from the carefully unrolled sheet iron tubes.

As can be readily understood from the description opportunity of
poisoning from volatilisation of arsenic and of arsenic compounds is
considerable. Metallic arsenic is used for making hard shot, and for
increasing the brilliancy and hardness of metal alloys (type metal, &c.).

_White arsenic_ (arsenic trioxide) is obtained by roasting with access of
air in reverberatory furnaces arsenical ores and smelting residues. The
vapours of white arsenic sublime and are condensed as a powder in long
walled channels or in chambers, and are resublimed in iron cylinders.
White arsenic is used in making colours, in glass (for decolourising
purposes), as an insecticide in the stuffing of animals, &c.

INDUSTRIAL ARSENIC POISONING.—In the _extraction of arsenic_ and
preparation of arsenious acid danger is present. But reliable accounts in
literature of poisoning among those engaged in arsenic works are wanting.

Those engaged in roasting operations and packing suffer much from skin
affections. Similar poisoning is reported in the smelting of other
arsenical ores—nickel, cobalt, lead, copper, iron, and silver, from
arsenic compounds present in the fumes. This is especially the case in
the smelting of tin, which generally contains arsenical pyrites.

Danger is present also in _unhairing_ (i.e. removing the wool from sheep
skins), since the skins imported from Buenos Aires and Monte Video are
treated with a preservative which, in addition to sodium nitrate, soda,
and potash, contains generally arsenious acid.

In _tanneries_ a mixture of arsenic sulphide (realgar) and lime is used
for unhairing. Arsenic is used also for preserving and stuffing animal
furs; but although affections of the skin are described I cannot find
reference to arsenical poisoning.

The inspector for East London in 1905 refers to severe eczematous
eruptions on face, neck, and hands, affecting workers in a _sheep dip_
works—mainly in the packing of the light powder in packets.

Formerly the use of arsenic in the manufacture of colours was great,
especially of _emerald (Schweinfurter) green_. This is made by dissolving
arsenious acid in potash with addition of acetate of copper. Drying and
grinding the material constitute the main danger. Scheele’s green is
another arsenical colour.

Use of _arsenic colours_ is becoming less and less. But in colour
printing of paper and colouring of chalk they are still employed. They
are used, too, as mordants in dyeing, but cases of poisoning from these
sources in recent years are not to be found.

The dust in many glass works contains, it is stated, as much as 1·5 per
cent of white arsenic.

Despite the numerous opportunities for arsenical poisoning in industries
it is rare or, at any rate, is only rarely reported.

ARSENIURETTED HYDROGEN POISONING.—Industrial poisoning from arseniuretted
hydrogen is caused mostly by inhalation of the gases developed by the
action on one another of acids and metals which contain arsenic. Hydrogen
gas as usually prepared for filling balloons gives occasion for poisoning.

In Breslau in 1902 five workmen became affected, of whom three died from
inhalation of arseniuretted hydrogen gas in filling toy balloons.[1]

Further, use of hydrogen in lead burning may expose to risk, and also
preparation of zinc chloride flux.

Of thirty-nine recorded cases of arseniuretted hydrogen poisoning twelve
were chemists, eleven workers filling toy balloons, seven aniline
workers, five lead smelters, three balloonists, and in one the origin
could not be traced. Nineteen of these proved fatal within from three to
twenty-four days.[2]

Cases are recorded (1) in the reduction of nitroso-methylaniline with
zinc and hydrochloric acid; (2) in the preparation of zinc chloride from
zinc ashes and hydrochloric acid; (3) from manufacture of zinc sulphate
from crude sulphuric acid and zinc dust; (4) in spelter works in the
refining of silver from the zinc crust with impure hydrochloric acid; and
(5) in the formation room of accumulator factories.

The English factory inspectors’ report describes in 1906 occurrence
of three cases in an electrolytic process for the recovery of copper
in which the copper dissolved in sulphuric acid was deposited at the
cathode, and hydrogen at the lead anode. In the 1907 report mention is
made of two cases, one affecting a chemist separating bismuth from a
solution of bismuth chloride in hydrochloric acid, and the other (which
proved fatal) a man who had cleaned a vitriol tank.

The poisoning resulting from ferro-silicon is in part referable to
development of arseniuretted hydrogen gas.


ANTIMONY

It seems doubtful if industrial poisoning can really be traced to
antimony or its compounds; generally the arsenic present with the
antimony is at fault. Erben[1] considers that industrial antimony
poisoning occurs among workmen employed in smelting antimony alloys in
making tartar emetic through inhalation of fumes of oxide of antimony.

A case is cited of a workman in Hamburg engaged in pulverising pure
antimony who was attacked with vomiting which lasted for several days,
and the inspector of factories noted epistaxis (nose bleeding) and
vomiting as following on the crushing of antimony ore.

Compositors in addition to chronic lead poisoning may suffer, it is
alleged, from chronic antimony poisoning, showing itself in diminution
in the number of white blood corpuscles and marked eosinophilia. These
changes in the blood could be brought about experimentally in rabbits.
Antimony was found by the Marsh test in the stools of those affected.


IRON

_Pig iron_ is obtained by smelting iron ores in blast furnaces (fig. 29),
through the upper opening of which charges of ore, limestone or similar
material to act as a flux, and coke are fed in succession. The furnaces
are worked continuously, using a blast of heated air; carbon monoxide is
produced and effects the reduction of the ore to molten iron. The latter
accumulates in the hearth and is covered with molten slag; this flows
constantly away through an opening and is collected in slag bogies for
removal, or is sometimes cooled in water.

The crude iron is tapped from time to time, and is led in a fluid
condition into moulds called ‘pigs,’ in which it solidifies. Cast iron is
occasionally used direct from the blast furnace for the purpose of making
rough castings, but generally it is further refined before being used in
a foundry by remelting with cast iron scrap in a cupola furnace.

[Illustration: FIG. 29.

_a_ Hearth; _b_ Bosh; _c_ Shaft; _d_ Gas uptake; _e_ Down-comer; _f_
Tuyères with water cooling arrangement; _g_ Blast pipes; _h_ Tapping
hole; _k_ Supporting columns; _l_ Furnace bottom; _m_ Charging hopper;
_n_ Bell with raising and lowering arrangement.]

_Wrought iron_ is made by treating pig iron in refinery and puddling
furnaces; in these much of the carbon is removed as carbon monoxide, and
from the puddling furnace the iron is obtained as a pasty mass which can
be worked into bars, rods, or plates.

_Steel_ is made in various ways. The Acid Bessemer process consists in
forcing compressed air in numerous small streams through molten cast
iron, in iron vessels (converters) which are lined with ganister, a
silicious sandstone. These can be rotated on trunnions. Basic Bessemer
steel is made in similar converters by the Thomas-Gilchrist or basic
process, which can be applied to pig irons containing phosphorus. The
latter is removed by giving the converter a basic lining of calcined
magnesium limestone mixed with tar.

In the _Martin_ process steel is obtained by melting together pig iron
with steel scrap, wrought iron scrap, &c., on the hearth of a Siemens
regenerative furnace with a silicious lining.

In iron smelting the most important danger is from _blast furnace
gas_ rich in carbonic oxide. Sulphur dioxide, hydrocyanic acid, and
arseniuretted hydrogen gas may possibly be present.

When work was carried out in blast furnaces with open tops the workers
engaged in charging ran considerable risk. But as the blast furnace gas
is rich in carbonic oxide and has high heating capacity these gases
are now always led off and utilised; the charging point is closed by a
cup (Parry’s cup and cone charger) and only opened from time to time
mechanically, when the workers retire so far from the opening as to be
unaffected by the escaping gas. The gas is led away (fig. 29) through a
side opening into special gas mains, is subjected to a purifying process
in order to rid it of flue dust, and then used to heat the blast, fire
the boilers, or drive gas engines.

Severe blast furnace gas poisoning, however, does occur in entering the
mains for cleaning purposes. Numerous cases of the kind are quoted in the
section on Carbonic oxide poisoning.

The gases evolved on tapping and slag running can also act injuriously,
and unpleasant emanations be given off in granulating the slag (by
receiving the fluid slag in water).

In the puddling process much carbonic oxide is present. Other processes,
however, can scarcely give rise to poisoning.

The _basic slag_ produced in the Thomas-Gilchrist process is a valuable
manure on account of the phosphorus it contains; it is ground in
edge runners, and then reduced to a very fine dust in mills and
disintegrators. This dust has a corrosive action already referred to in
the chapter on Phosphorus and Artificial Manures.

The poisoning caused by _ferro-silicon_ is of interest. Iron with high
proportion of silicon has been made in recent years on a large scale
for production of steel. Some 4000 tons of ferro-silicon are annually
exported to Great Britain from France and Germany. It is made by
melting together iron ore, quartz, coke, and lime (as flux) at very
high temperature in electrical furnaces. The coke reduces the quartz
and ore to silicon and metal with the production of ferro-silicon.
Certain grades, namely those with about 50 per cent. silicon, have
the property of decomposing or disintegrating into powder on exposure
for any length of time to the air, with production of very poisonous
gases containing phosphoretted and arseniuretted hydrogen. The iron and
quartz often contain phosphates, which in presence of carbon and at the
high temperature of the electrical furnace would no doubt be converted
into phosphides combining with the lime to form calcium phosphide;
similarly any arsenic present would yield calcium arsenide. These
would be decomposed in presence of water and evolve phosphoretted and
arseniuretted hydrogen gas. In addition to its poisonous properties it
has also given rise to explosions.

[In January 1905 fifty steerage passengers were made seriously ill and
eleven of them died. In 1907 five passengers died on a Swedish steamer
as the result of poisonous gases given off from ferro-silicon, and
more recently five lives were lost on the steamer _Aston_ carrying
the material from Antwerp to Grimsby.[C] This accident led to full
investigation of the subject by Dr. Copeman, F.R.S., one of the Medical
Inspectors of the Local Government Board, Mr. S. R. Bennett, one of H.M.
Inspectors of Factories, and Dr. Wilson Hake, Ph.D., F.I.C., in which the
conclusions arrived at are summarised as follows:

    1. Numerous accidents, fatal and otherwise, have been caused
    within the last few years by the escape of poisonous and
    explosive gases from consignments of ferro-silicon, which,
    in every instance, have been found to consist of so-called
    high-grade ferro-silicon, produced in the electric furnace.

    2. These accidents, for the most part, have occurred during
    transport of the ferro-silicon by water, whether in sea-going
    vessels or in barges and canal-boats plying on inland waters.

    3. These accidents have occurred in various countries and on
    vessels of different nationalities, while the ferro-silicon
    carried has, in almost every instance, been the product of a
    different manufactory.

    4. Ferro-silicon, especially of grades containing from 40 per
    cent. to 60 per cent. of silicon, is invariably found to evolve
    considerable quantities of phosphoretted hydrogen gas, and, in
    less amount, of arseniuretted hydrogen, both of which are of a
    highly poisonous nature. A certain amount of the gas evolved
    is present, as such, in the alloy, being ‘occluded’ in minute
    spaces with which its substance is often permeated.

    5. As the result of careful investigation, it has been
    shown that certain grades of ferro-silicon—notably such as
    contain about 33 per cent., 50 per cent., and 60 per cent. of
    silicon—even when manufactured from fairly pure constituents,
    are both brittle and liable to disintegrate spontaneously, this
    latter characteristic being apt to be specially marked in the
    case of the 50 per cent. grade.

    All these grades are commonly employed at the present time.

    6. In the event of disintegration occurring, the amount of
    surface exposed will, obviously, be greater than if the mass
    were solid.

    7. Evolution of poisonous gases is greatly increased by the
    action of moisture, or of moist air, under the influence
    of which phosphoretted hydrogen is generated from calcium
    phosphide, which, in turn, is formed, in large part, at any
    rate, from the calcium phosphate present in anthracite and
    quartz, at the high temperature of the electric furnace. If
    spontaneous disintegration of the alloy also occurs, much
    larger quantities of gas would be given off from such friable
    and unstable material, other conditions being equal. The
    greater or less tendency of a given sample to evolve poisonous
    gases, and even a rough estimate of their probable amount may
    be arrived at by the use of test-papers prepared with silver
    nitrate.

    8. There is no evidence that low-grade ferro-silicon (10 to
    15 per cent.), produced in the blast-furnace, has ever given
    rise to accidents of similar character to those known to have
    been caused by the high-grade electrically produced alloy.
    Blast-furnace ferro-silicon does not evolve poisonous gases
    even in presence of moisture.

    9. As regards ferro-silicon produced in the electric furnace,
    the evidence available goes to show that certain percentage
    grades are practically quite innocuous. This statement applies
    to grades of alloy of a silicon content up to and including
    30 per cent., and probably also, though in considerably less
    degree, to those of 70 per cent. and over.

    10. In view of the fact that the use of ferro-silicon of grades
    ranging between 30 per cent. and 70 per cent. apparently is
    not essential in metallurgical operations, with the possible
    exception of basic steel manufacture, it will be advisable that
    the production of this alloy of grades ranging between these
    percentages should be discontinued in the future.

    11. The proprietors of iron and steel works making use
    of ferro-silicon will assist in the protection of their
    workpeople, and at the same time act for the public benefit by
    restricting their orders to grades of this material, either
    not exceeding 30 per cent., or of 70 per cent. and upwards,
    according to the special nature of their requirements.

    12. But as, pending international agreement on the question,
    intermediate percentages of ferro-silicon will doubtless
    continue to be manufactured and sold, the issue, by the Board
    of Trade, of special regulations will be necessary in order to
    obviate, so far as may be possible, chance of further accidents
    during the transport of this substance.

    _Inter alia_, these regulations should require a declaration
    of the nature, percentage, date of manufacture, and place of
    origin of any such consignment.

The suggested regulations are printed on p. 291.]


ZINC

Industrial poisoning from zinc is unknown. The chronic zinc poisoning
among spelter workers described by Schlockow with nervous symptoms is
undoubtedly to be attributed to lead.


COPPER: BRASS

_Occurrence of brass-founder’s ague._—Opinion is divided as to whether
pure copper is poisonous or not. Lehmann has at any rate shown
experimentally that as an industrial poison it is without importance.

Occurrence, however, of brass-founder’s ague is undoubtedly frequent.
Although neither pure zinc nor pure copper give rise to poisoning, yet
the pouring of brass (an alloy of zinc and copper) sets up a peculiar
train of symptoms. As the symptoms are transient, and medical attendance
is only very rarely sought after, knowledge of its frequency is difficult
to obtain.

Sigel,[1] who has experimented on himself, believes that the symptoms
result from inhalation of superheated zinc fumes. In large well-appointed
brass casting shops (as in those of Zeiss in Jena) incidence is rare.

Lehmann[2] very recently has expressed his decided opinion that
brass-founder’s ague is a zinc poisoning due to inhalation of zinc
oxide and not zinc fumes. This conclusion he came to as the result of
experiments on a workman predisposed to attacks of brass-founder’s ague.
Lehmann’s surmise is that the symptoms are due to an auto-intoxication
from absorption of dead epithelial cells lining the respiratory tract,
the cells having been destroyed by inhalation of the zinc oxide. He found
that he could produce typical symptoms in a worker by inhalation of the
fumes given off in burning pure zinc.

_Metal pickling._—The object of metal dipping is to give metal objects,
especially of brass (buckles, lamps, electric fittings, candlesticks,
&c.), a clean or mat surface and is effected by dipping in baths of
nitric, hydrochloric, or sulphuric acid. Generally after dipping in
the dilute bath the articles go for one or two minutes into strong
acid, from which injurious fumes, especially nitrous fumes, develop
with occasionally fatal effect (see the chapter on Nitric Acid).
Unfortunately, there are no references in the literature of the subject
as to the frequency of such attacks.

Recovery of gold and silver has been already referred to in the chapters
on Mercury, Lead, and Cyanogen.

Mention must be made of _argyria_. This is not poisoning in the proper
sense of the word, as injury to health is hardly caused. Argyria results
from absorption of small doses of silver salts which, excreted in the
form of reduced metallic silver, give the skin a shiny black colour.
Cases are most frequently seen in silverers of glass pearls who do the
work by suction. Local argyria has been described by Lewin in silvering
of mirrors and in photographers.




III. OCCURRENCE OF INDUSTRIAL POISONING IN VARIOUS INDUSTRIES


The most important facts have now been stated as to the occurrence of
poisoning in industry, and there remain only a few gaps to fill in and to
survey briefly the risks in certain important groups of industry.


TREATMENT OF STONE AND EARTHS

Lime Burning: Glass Industry

Lead poisoning in the ceramic industry (earthenware, porcelain, glass,
polishing of precious stones, &c.) has been dealt with in detail in the
chapter on Lead. There is further the possibility of chrome-ulceration,
of arsenic poisoning, and conceivably also of manganese. Further,
poisoning by _carbonic oxide_ and carbon dioxide may occur from the
escape of furnace gases where hygienic conditions are bad. In charging
lime kilns poisoning by carbonic oxide has occurred. The report of the
Union of Chemical Industry in 1906 describes the case of a workman who
was assisting in filling the kiln with limestone. As the furnace door
was opened for the purpose gas escaped in such amount as to render him
unconscious. He was picked up thirty minutes later, but efforts at
resuscitation failed.

Carbonic oxide poisoning, again, may arise from the use of Siemens
regenerative furnaces, especially glass furnaces: details are given in
the chapter on Illuminating Gas.

_Hydrofluoric acid_ is present as an industrial poison in _glass etching_
(see Fluorine Compounds). Persons employed in this process suffer from
inflammation of the respiratory tract and ulceration of the skin of the
hands. I could not find any precise statement as to the frequency of the
occurrence of such injuries. Use of sand-blasting to roughen the surface
of glass has to some extent taken the place of etching by hydrofluoric
acid.


TREATMENT OF ANIMAL PRODUCTS

In _tanning_ use of arsenic compounds for detaching the wool from skins
and of gas lime for getting rid of hair may cause injury to health. With
the latter there is possibility of the action of cyanogen compounds (see
the chapters on Arsenic and Cyanogen).


PREPARATION OF VEGETABLE FOOD STUFFS AND THE LIKE

In _fermentation_ processes as in breweries and the sugar industry
accumulations of carbonic acid gas occur, and suffocation from this
source has been repeatedly described. Mention in this connection
should be made of the use of salufer containing some 2 per cent. of
silicofluoric acid as a preservative and antiseptic in beer brewing. In
the _sulphuring_ of hops, wine, &c., the workers may run risk from the
injurious action of sulphur dioxide. _Arsenic_ in the sulphuric acid
used for the production of _dextrine_ may set up industrial poisoning.
Poisoning from _ammonia_ gas can occur in _cold storage_ premises.
Industrial poisoning from tobacco is not proved, but the injurious effect
of the aroma and dust of tobacco—especially in women—in badly arranged
tobacco factories is probable.


WOOD WORKING

_Injurious woods._—In recent literature there are several interesting
references to injury to health from certain poisonous kinds of wood—skin
affections in workers manipulating satinwood, and affections of the heart
and general health in workers making shuttles of African boxwood. Details
of these forms of poisoning are reported from England and Bavaria. The
wood used for making the shuttles was West African boxwood (Gonioma
Kamassi). It appears that the wood contains an alkaloidal poison which
affects the heart’s action. The workers suffered from headache, feeling
of sleepiness, lachrymation, coryza, difficulty of breathing, nausea, and
weakness. Four workers had to give up the work because of the difficulty
in breathing. Inquiry was made by Dr. John Hay of Liverpool in 1908 and
by the medical inspector of factories in 1905. The following table shows
the symptoms found:

    +----------------------+-----------------------------------+
    |                      |            Persons Examined.      |
    |                      +-----------------+-----------------+
    |      Symptoms.       |       1905.     |   1907-1908.    |
    |                      +-------+---------+-------+---------+
    |                      |Number.|Per cent.|Number.|Per Cent.|
    |         (1)          |  (2)  |   (3)   |  (4)  |  (5)    |
    +----------------------+-------+---------+-------+---------+
    |Headache              |   27  |  24·1   |   18  |  22·8   |
    |Feeling of somnolence |   10  |   9·0   |   17  |  21·5   |
    |Running of eyes       |   13  |  11·6   |    9  |  11·3   |
    |Running of nose       |   28  |  25·0   |   20  |  28·0   |
    |Breathing affected    |   34  |  30·4   |   13  |  16·4   |
    |Nausea or sickness    |   13  |  11·6   |    3  |   3·8   |
    |Faintness or weakness |   11  |   9·6   |    1  |   1·2   |
    +----------------------+-------+---------+-------+---------+

The later inquiry shows considerable diminution in the amount of
complaint as to respiratory trouble. This may have been due to the
improved conditions of working, freely acknowledged by the men. Men were
examined who had complained of the effects of the wood in 1905, and had
continued uninterruptedly at the same kind of work during the interval
without any obvious further injury to their health, although they
preferred working on other woods.

East Indian boxwood had to be discarded in the shuttle trade owing to
its irritant action on the eyes. Sabicu wood from Cuba was stated to
give off ‘a snuffy dust under the machine and hand planes, the effect of
which upon the worker is to cause a running at the eyes and nose, and a
general feeling of cold in the head. The symptoms pass off in an hour or
so after discontinuance of work.’ Reference was made in the report for
1906 to eczematous eruptions produced by so-called Borneo rosewood, a
wood used owing to its brilliant colour and exquisite grain in fret-saw
work. The Director of the Imperial Institute experimented with this wood,
but failed to discover injurious properties in it. At the same time
experiments with the wood and sawdust of East and West Indian satinwood
were undertaken, but also without result.

From inquiries subsequently made it appeared that much confusion existed
as to the designation ‘satinwood,’ as under this name were classed both
East and West Indian satinwood and also satin walnut. The evidence was
clear that East Indian satinwood was more irritating than West Indian.
Satin walnut wood is apparently harmless. In the shipbuilding yards of
East London, Glasgow, and Bristol affections of the skin were recognised,
but susceptibility to the wood varied. One man asserted that merely
laying a shaving on the back of his hand would produce a sore place. The
injurious effects here seem to disappear quickly. Exhaust ventilation is
applied, but there is a tendency to give up the use of the wood.

Isolated cases of illness have been ascribed to working teak and olive
wood. In Sheffield the following are held to be irritating: ebony,
magenta rosewood, West Indian boxwood, cocos wood. Some kinds of mahogany
are said to affect the eyes and nose.

Use of methylated spirit in polishing furniture is said to lead to injury
to health although not to set up actual poisoning. Lead poisoning can
occur from the sand-papering of coats of paint applied to wood.

In impregnating wood with creosote and tar the effects on the skin noted
in the chapter on Tar are observed.


TEXTILE INDUSTRY

In getting rid of the grease from animal wool carbon bisulphide or
_benzine_ may be used.

The process of _carbonising_ in the production of shoddy may give rise to
injury to health from acid fumes. Lead poisoning used to be caused by the
knocking together of the leaden weights attached to the Jacquard looms.
This is a thing of the past, as now iron weights are universal.

Opportunity for lead poisoning is given in the weighting of
yarn—especially of silk with lead compounds.

In _bleaching_ use of chlorine and sulphur dioxide has to be borne in
mind.

In _chemical cleaning_ poisoning by benzine may occur.

In _dyeing_ and _printing_ use of poisonous colours is lessening, as
they have been supplanted by aniline colours. On occurrence of aniline
poisoning in aniline black dyeing see the section on Aniline. Use of lead
colours and of chromate of lead are dealt with in special sections.




PART II

_THE SYMPTOMS AND TREATMENT OF INDUSTRIAL POISONING_


In this section the most important diseases and symptoms of industrial
poisoning will be described. In doing this—considering the mainly
practical purpose of this book—theoretical toxicological details and any
full discussion of disputed scientific points will be omitted.




I. INTRODUCTORY


Hitherto in this book we have intentionally followed the inductive
method, from the particular to the general: we began by citing a
number of important instances of industrial poisoning, but only now
will endeavour be made to give a definition of the terms ‘poison’ and
‘poisoning.’

Attempts at such definitions are numerous; every old and new text-book
of toxicology contains them. A few only hold good for our purpose. It
is characteristic that Lewin, after attempting a definition of the
conception ‘poisoning,’ himself rejects it and declares that he can see
no practical disadvantage in the impossibility of defining this notion,
because deductions based upon the knowledge of undoubted cases can never
be dispensed with, even if a definition were possible: one justification
the more for our inductive method.

But we will not quite dispense with a definition.

_Poisons are certain substances which are able chemically to act on an
organism in such a way as to effect a permanent or transient injury to
its organs and functions; an injury consequently to the health and
well-being of the person affected; this injury we call poisoning._

In the present book we have refrained from including industrial
infections among industrial poisonings, and the subject has been limited
to poisoning in the restricted and current sense of the word.

An industrial poison is a poison employed, produced, or somehow
occasioned in industrial occupation, which is brought about
inadvertently, and consequently against the will of the person poisoned.

From a simple survey of the action of industrial poisons in general we
may group them as follows:

    1. Poisons which act _superficially_, i.e. which cause in the
    organs which they touch gross anatomical lesions (irritation,
    corrosion, &c.)—so-called contact-effect. To this class belong
    especially irritant and corrosive poisons.

    2. _Blood_ poisons, i.e. poisons which are absorbed by the
    blood and change it; this change can affect either the blood
    colouring-matter, with which certain poisons form chemical
    compounds, or the blood corpuscles themselves can be altered or
    destroyed (for instance, poisons having a hæmolytic action).

    3. Poisons with definite _internal_ action, so-called remote or
    specific effect. To this class belong the poisons which, after
    being absorbed into the system, act upon definite organs or
    tissues in a specific manner (nerve poisons, heart poisons, &c.).

It is indeed possible for one and the same poison to display two or all
three of these modes of action.

The effect of poison depends upon an interaction of the poison and the
organism, or its single organs. Selection as regards quality and quantity
is a property of the organism as well as of the poison: the nature and
amount of the poison taken in are determining factors on the one side,
and on the other the constitution, size, and weight of the affected
organism. The chemical constitution of the poisonous substance determines
the qualitative property of the poison.

Further, certain physical properties of the poison determine its action,
especially its form, solubility in water, and its power of dissolving
fat. These affect its susceptibility to absorption, to which point we
shall return shortly; the hygroscopic capacity of a poison produces a
highly irritant and corrosive action.

Industrial poisons can be absorbed (1) as solid substances, (2) as
liquids, and (3) as gases. Since industrial poisoning, as defined
above, is of course neither desired nor intended by the sufferer, who
unsuspectingly takes into his system poison used or developed in the
factory, solid substances in finely divided condition—in the form of
dust—can be considered as industrial poisons. Accordingly, industrial
poisons can be classed as due to dust, gases, and liquids.

The poison may be introduced into the body through the functional
activity of the organism by the lungs or alimentary tract, or it may
penetrate the uninjured or injured surface of the skin.

Industrial poisons which contaminate the air of the factory are
inhaled—these are consequently either poisonous dusts or gases and
vapours.

As a rule, only industrial poisons in a liquid form enter through the
skin, which may be either intact or wounded; gaseous poisons seldom do;
poisons in the form of fat or dust can only pass through the skin after
they have been first dissolved by the secretions of the skin or of a
wound, so that they come to be absorbed in solution. Most frequently
those liquid poisons which are capable of dissolving the fat of the skin
are thus absorbed, and next, such liquids as have a corrosive effect,
breaking down the resistance of the skin covering and producing an
inflamed raw surface. But such poisons much more easily enter through the
mucous membrane, as this naturally offers a much weaker resistance than
the skin.

From a quantitative point of view it is especially the amount of poison
actively assimilated which determines the effect. Every poison is without
effect if assimilated in correspondingly small quantities. There is
consequently a minimum poisonous dose, after which the poison begins to
act; but this minimum dose can only be ascertained and specified when the
qualitative properties and the weight of the organism are also taken
into consideration; it has therefore a relative value. The strongest
effect which a poison is able to produce is the destruction of the life
functions of the organism, the fatal effect. This fatal dose, however,
can only be determined relatively to the qualities of the organism in
question.

Not only is the absolute quality of the poison of decisive significance,
but the degree of concentration often influences its action, that is
to say, the greater or less amount of effective poison contained in
the substance conveying it into the organism; concentration plays an
important part in many industrial poisons, especially, as is obvious, in
corrosive poisons.

A further important point is the time which it takes to absorb the
poison. The action of the poison—the whole expression of the symptoms of
poisoning—is essentially influenced by this fact.

Usually gradual and repeated absorption of small quantities produces slow
onset of symptoms, while sudden absorption of larger quantities of poison
brings about rapid onset of illness. In the former case the poisoning
is called _chronic_, in the latter, _acute_. Acute industrial poisoning
is sometimes so sudden that the affected person cannot withdraw himself
in time from the influence of the poison, nor prevent its entrance in
considerable quantities into his system; this is often caused by the
fact that the effect of the poison is so rapid that he is often suddenly
deprived of power to move or of consciousness, and remains then exposed
to the action of the poison until help comes. Such accidents are mostly
caused by poisonous gases. Occasionally also considerable quantities of
poison enter quite unnoticed into the body, such as odourless poisonous
gases in breathing, or poisonous liquids through the skin. In chronic
industrial poisoning unsuspected accumulation of poison takes place,
until symptoms of illness ultimately reveal themselves; as the first
stages of poisoning are not recognised in time by the person affected,
he continues exposed to the influence of the poison for weeks, months,
even years, until the chronic effect has reached its full development and
becomes obvious. Such insidious industrial poisoning arises through the
continual absorption into the lungs or stomach of small quantities of
poisonous dust, gases, and vapours, during constant or frequent work in
an atmosphere containing such gases; poisonous liquids also, by soiling
hands and food, or by penetrating the skin, can produce slow industrial
poisoning.

Industrial poisoning which in respect of its duration stands midway
between acute and chronic is called sub-acute poisoning. This usually
means that more frequent absorption of greater quantities of poison has
taken place, though not in doses large enough to produce an immediately
acute effect. This is important legally because industrial poisonings
caused through the sudden absorption of poison in sufficient quantity
to act immediately or to bring about subsequent symptoms of poisoning,
are reckoned as accidents. Thus acute and many sub-acute industrial
poisonings are accounted accidents. Chronic industrial poisonings,
acquired gradually, count as illnesses. But as in certain cases it
cannot be decided whether sudden or gradual absorption of the industrial
poison is in question, this distinction is an unnatural one. It is also
unnatural in the legal sense, for there is often no material reason for
regarding as legally distinct cases of chronic and acute industrial
poisoning. To this we shall refer later in discussing the question of
insurance against industrial poisoning.

We have from the outset assumed that the effect of the poison depends
not only on the nature of the poison itself, but also on that of the
organism, considered both quantitatively and qualitatively.

Significant in a quantitative respect is the body weight of the organism,
and the fatal dose of the poison must be ascertained and stated in
connection with the body weight, calculated as a rule per kilo of the
live weight.

The qualitative point of view must reckon with the differing
susceptibility of organisms for poison. This varying susceptibility to
the action of poison, the causes of which are very obscure, is called
disposition.

Different species (of animals and men) exhibit often very different
degrees of susceptibility towards one and the same poison; the
differences in this respect are often very considerable, and one cannot
simply transfer the experience experimentally gained from one species of
animal to man or another species of animal, without further experiment.
Besides disposition, sex, and still more age, often determine within the
same species marked difference of susceptibility to a poison. Further,
there is an individual disposition due to qualities peculiar to the
individual, which makes some persons more than usually immune and others
specially susceptible. Individuals weakened by illness are particularly
susceptible to poisoning. Two diseases, in especial, favour the operation
of poison, influencing disastrously the capacity for assimilating
food, and reducing the general resisting power of the body; of these
tuberculosis stands first.

Individual disposition plays in industrial poisoning a part which must
not be under-estimated; it determines the possibility of acclimatisation
to a poison; some individuals capable of resistance habituate
themselves—often comparatively easily—to a poison, and become, up to a
certain limit, immune against it, that is, they can tolerate a quantity
which would be injurious to others not so accustomed. With other
individuals, however, the opposite effect is apparent. Repeated exposure
to the action of the poison leads to an increased susceptibility, so
that acclimatisation is not possible. Innate hyper-sensitiveness of the
individual towards a poison is called idiosyncrasy. Frequently, for
example, this quality shows itself as hyper-sensitiveness of the skin
towards the harmful action of certain poisons. A marked lowering in the
sensitiveness, innate or acquired, of the organism towards a poison is
called immunity.

The possibility of the absorption and action of a poison
presupposes—speaking generally—its solubility, and indeed its solubility
in the body juices.

In general, poison can be absorbed at very different points of the body;
so far as industrial poisons are concerned, these are the mucous membrane
of the respiratory passages, the mucous membrane of the digestive tract,
and the skin, intact or broken. The rapidity of absorption depends on the
nature of the poison, of the individual, and the channel of absorption.
Of industrial poisons gases are relatively the most quickly absorbed;
sometimes indeed so swiftly that the effect follows almost immediately.

Elimination of industrial poisons is effected principally by the
kidneys, the intestinal canal, the respiratory organs, and, more rarely,
the skin. Rapidity of elimination also depends on the nature of the
poison and of the person poisoned.

If elimination is insufficient, or absorption takes place more quickly
than excretion, the poison accumulates in the body, and has a cumulative
effect which in chronic industrial poisonings plays a very important
rôle. Under certain circumstances poisons are not thrown off, but stored
up—fixed—in the body.

The poison absorbed in the body can act unchanged from the place where it
is stored. A number of poisons, however, undergo in the organism chemical
change through which the action of the poison is partly lessened,
rarely increased. Among such changes and weakening of the poison are:
oxidation, as, for example, of organic poisons into their final products
(carbonic acid, water, &c.), oxidation of benzene into phenol, oxidation
of sulphur dioxide into sulphuric acid, &c.; reduction in the case of
metals, peroxides, &c.; neutralisation of acids by alkaline juices;
chemical union (for instance, of aromatic compounds with sulphuric acid).
The splitting up of albuminous bodies is not of importance in regard to
industrial poisons.


GENERAL REMARKS ON THE TREATMENT OF INDUSTRIAL POISONINGS

Although in industrial poisoning the importance of treatment is small in
comparison with that of preventive measures, in discussing particular
forms of poisoning, full weight must be given to it; and in order to
avoid repetition, certain points will be brought forward here.

Of the treatment of chronic industrial poisonings not much in general can
be said; unfortunately, special treatment has often little chance. It
will usually be of advantage to maintain the activity of the excretory
organs. So far as there is question of poisons affecting metabolism and
injuriously influencing the general state of nutrition, treatment aiming
at improving the general health and strength offers hope of success.
For nervous symptoms, especially paralysis, disturbance in sensation,
&c., treatment generally suitable to nervous diseases can be tried
(electro-therapeutics, baths, &c.). In treatment of acute industrial
poisonings, which often demand the prompt intervention of laymen, ‘first
aid’ is more hopeful.

The most important general rules of treatment arise in reference to
irritant poisons which produce ulceration of the skin, and further in
regard to those poisons which cause unconsciousness, especially blood
poisons.

When an irritant poison is acting on the skin, the first object to be
aimed at is naturally the immediate removal of the cause of corrosion
by water, or, better still, neutralisation by an alkaline solution (for
example, soda solution) in the case of corrosive acids, and weak acids
(organic acids, acetic acid, citric acid) in the case of caustic action
by alkalis. Such remedies must be at hand in factories as part of the
equipment for first aid, where irritant poisonings can occur.

In those industrial poisonings which result in loss of consciousness,
arrest of respiration and suffocation, attempts at resuscitation should
at once be made. In these attempts at resuscitation, _artificial
respiration_ is of the greatest importance; of course the sufferer must
first be withdrawn from the influence of the poison, i.e. be brought into
fresh air. Great care must be taken, especially where it is necessary to
enter places filled with a poisonous atmosphere, to prevent the rescuers,
as is often the case, themselves falling victims to the influence of the
poison. They should be provided with suitable smoke helmets or breathing
apparatus.

We will not describe the methods of resuscitation and artificial
respiration universally enjoined; they can be found in every first-aid
handbook.

Emphasis is laid on the great importance of _treatment by oxygen_ in
cases of industrial poisoning through gaseous blood poisons, as this
treatment is attended with good results. Apparatus for the administration
of oxygen should be kept wherever there exists the possibility of such
poisoning, especially in mines, smelting works, chemical factories, and
chemical laboratories.

Oxygen treatment rests on the fact that by raising the pressure of the
oxygen from 113 mm., as it is generally in ordinary air, to 675 mm.,
which is reached in presence of pure oxygen, the quantity of oxygen
absorbed in the blood rises from 0·3 to 1·8 per 100 c.c. Further,
the saturation of the hæmoglobin, the colouring matter of the blood,
undergoes an increase of 2·4 per cent. This increase of oxygen in the
blood can save life in cases where through poisoning a deficiency of
oxygen has resulted.

The introduction of oxygen is done by special apparatus which acts
essentially on the principle that during inhalation oxygen is pressed
into the lungs which are below normal physiological pressure, while
exhalation is effected by a deflating arrangement when the poisoned
individual no longer breathes of his own accord. When natural breathing
begins, the introduction of oxygen without special apparatus generally
suffices.

[Illustration: FIG. 30.—Dräger’s Oxygen Box

I Oxygen cylinder; A Valve on cylinder; B Manometer; C Key for opening
and closing the flow of oxygen; F Economiser; H Facepiece.]

Dräger’s _oxygen apparatus_ (fig. 30) consists of a small oxygen cylinder
provided with a closing valve, a small manometer, a so-called ‘automatic’
reducing valve with an arrangement for opening and closing the oxygen
supply, a bag to act as a receiver or economiser, a breathing mask, and
a metal tube connecting the breathing mask with the other parts of the
apparatus. The oxygen cylinder, when filled, contains about 180 litres of
oxygen, and the manometer allows the manipulator to control at any time
whatever oxygen it still contains. The automatic arrangement not only
reduces the pressure but at the same time controls the supply of oxygen.
This dose is fixed at three litres of oxygen per minute, so that the
apparatus with the same oxygen cylinder will last for sixty minutes. The
oxygen is not inhaled pure, but is mixed with atmospheric air according
to need, and in order to make this possible the breathing mask is
provided with a small hole through which atmospheric air finds entrance.

[Illustration: FIG. 31.—Oxygen Inhaling Apparatus]

[Illustration: FIG. 32.—Showing apparatus in use (_Siebe, Gorman & Co._)]

As the oxygen flows continuously from the cylinder waste during
exhalation is prevented by the economiser, in which, during exhalation,
the inflowing oxygen accumulates, to be absorbed again in inhalation. A
small relief valve in the screw head of the bag prevents the entrance
into it of exhaled air.

[Illustration: FIG. 33.—Dräger’s Pulmotor (_R. Jacobson_)]

Another oxygen inhaling apparatus for resuscitating purposes, that of
Siebe, Gorman & Co., is illustrated in figs. 31 and 32.

Dräger also constructs an apparatus called the ‘Pulmotor’ which
simultaneously accomplishes the introduction of oxygen and artificial
respiration.

Inflation and deflation are effected by an injector driven by compressed
oxygen; this alternately drives fresh air enriched with oxygen into the
lungs and then by suction empties them again. While with the mechanical
appliances of resuscitation belonging to older systems the hand of the
helper regulated the rate of breathing, in the case of the Pulmotor
the lungs, according to their size, automatically fix the rate of
breathing; as soon as the lungs are filled the apparatus of its own
accord marks the moment for ‘deflation,’ and as soon as they are emptied
of ‘inflation.’ This automatic reversal is effected by a little bellows
which is connected with the air tubes. During inflation the same pressure
is exerted in the bellows as in the lungs. As soon as the lungs are
filled, the pressure in the bellows increases and it expands, its forward
movement causing the reversal to deflation. When the lungs are emptied
the bellows contracts, and through this contraction results the reversal
to inflation.

If, in an exceptional case, the breathing for some reason does not act
automatically, the hand of the helper can manipulate it by means of a
backward and forward movement of a lever. According to choice, either a
nose-mask or a mask covering both mouth and nose can be worn.

Combined with the regular apparatus for resuscitation is an ordinary
apparatus for the inhalation of oxygen; by the simple altering of a
lever, either the one or the other can be employed.




II. INDUSTRIAL POISONING IN PARTICULAR INDUSTRIES


After the foregoing general remarks we may now consider various points of
view in regard to classification of industrial poisonings into groups:

    (1) Toxicological, based on the action of the poisons.

    (2) Chemical, based on the chemical composition of the poisons.

    (3) Physical, based on the varying density of the poisons.
    (Division into solid (in form of dust), gaseous, and liquid
    poisons.)

To which may be added:

    (4) Classification according to the source of the poisoning and
    therefore according to industry, upon which Part I is mainly
    based.

In this section (Part II) a system is adopted which takes into
consideration as far as possible all the principles of division mentioned
above, in order to classify industrial poisonous substances in such a
manner that general practical conclusions can be clearly drawn, and
supervision rendered easy.


_GROUP: MINERAL ACIDS, HALOGENS, INORGANIC HALOGEN COMPOUNDS, ALKALIS_

Common to this group is a strong corrosive and irritant effect, varying
however in degree; as gases this group corrode or inflame the mucous
membrane of the respiratory passages, and in liquid form or in solution,
the skin.

Besides this superficial effect single members of this group, especially
those containing nitrogen, produce a remote effect upon the blood.

After absorption of the acids a decrease in the alkalinity of the blood
can take place and in its power to take up carbonic acid, thus vitally
affecting the interchange of gases in the body, and producing symptoms of
tissue suffocation.

As regards treatment in the case of acids and alkalis, neutralisation
has been already mentioned; further, oxygen treatment may be recommended
in cases where the blood has been injuriously affected. In cases of
poisoning through breathing in acid vapours, inhalation of extremely
rarefied vapour of ammonia or of a spray of soda solution (about 1 per
cent.) is advisable.


MINERAL ACIDS

=Hydrochloric Acid= (HCl) is a colourless, pungently smelling gas which
gives off strong white fumes. Experiments on animals, carefully carried
out by Leymann, produced the following symptoms.

Even in a concentration of 2-5 per thousand clouding of the cornea
ensues, and after about an hour inflammation of the conjunctiva, violent
running from every exposed mucous membrane with marked reddening, and
frequently inflammation (necrosis) of the septum of the nose; the lungs
are distended with blood, here and there hæmorrhages occur in the
respiratory and also in the digestive tracts. The animal dies of œdema
(swelling) of the lungs and hæmorrhage into the lungs if exposed long
enough to the action of HCl, even though (according to Lehmann) there may
not be accumulation of HCl in the blood; the chief effect is the irritant
one; 1·5-5 per thousand parts HCl in the air suffices, after three or
four hours’ exposure, to affect smaller animals (rabbits) so much that
they die during the experiment or shortly after it. Man can tolerate an
atmosphere containing 0·1 to 0·2 per thousand HCl; a somewhat greater
proportion of HCl produces bronchial catarrh, cough, &c.

The solution of hydrochloric acid in water is about 40 per cent. Simply
wetting the skin with concentrated solution of hydrochloric acid does not
generally have an irritant effect unless persisted in for some time; the
action of the acid, when continued, has a marked effect upon the mucous
membranes and upon the eyes.

The same treatment already recommended in the introductory remarks on
poisoning by inhalation of acid fumes in general applies.

=Hydrofluoric Acid= (HFl), a pungently smelling, colourless gas, causes
even in weak solutions (0·02 per cent.) irritant symptoms (catarrh of the
mucous membrane of the respiratory organs, lachrymation, &c.). Stronger
solutions set up obstinate ulcers, difficult to heal, in the mucous
membrane and the skin.

=Silico-fluoric Acid= (H₂SiFl₆) produces an analogous though somewhat
less marked corrosive action.

As regards treatment the reader is again referred to the introductory
sentences on this group.

=Sulphur Dioxide= (SO₂) is a colourless, pungently smelling gas which,
acting in low concentration or for a short period, causes cough and
irritation of the mucous membrane of the respiratory passages and of the
eyes; acting for a longer period, it sets up inflammation of the mucous
membrane, bronchial catarrh, expectoration of blood, and inflammation of
the lungs.

As Ogata and Lehmann have proved by experiments—some of them made on
man—a proportion of 0·03-0·04 per thousand of sulphur dioxide in the air
has a serious effect on a person unaccustomed to it, while workmen used
to this gas can tolerate it easily.

As sulphur dioxide probably does not affect the blood, treatment by
oxygen inhalation is useless. Otherwise the treatment spoken of as
applying to acid poisonings in general holds good.

=Sulphuric Acid= (H₂SO₄). Concentrated sulphuric acid occasionally
splashes into the eye or wets the skin, causing severe irritation and
corrosion, unless the liquid is quickly washed off or neutralised. If the
action of the acid persists, the corrosive effect becomes deepseated and
leads to disfiguring scars.

=Nitrous Fumes, Nitric Acid.=—Nitric oxide (NO) oxidises in the air
with formation of red fumes composed of nitrogen trioxide (N₂O₃) and
nitrogen peroxide (NO₂). These oxides are contained in the gases evolved
from fuming nitric acid and where nitric acid acts upon metals, organic
substances, &c.

Industrial poisoning by nitrous fumes is dangerous; unfortunately it
frequently occurs and often runs a severe, even fatal, course; sometimes
numerous workers are poisoned simultaneously. The main reason why nitrous
fumes are so dangerous is because their effect, like that of most other
irritant gases, is not shown at once in symptoms of irritation, such
as cough, cramp of the glottis, &c., which would at least serve as a
warning to the affected person; on the contrary, generally no effect at
all is felt at first, especially if the fumes are not very concentrated.
Symptoms of irritation usually appear only after some hours’ stay in
the poisonous atmosphere. By this time a relatively large quantity of
the poisonous gas has been absorbed, and the remote effect on the blood
induced.

The first symptoms of irritation (cough, difficulty of breathing,
nausea, &c.) generally disappear when the affected person leaves the
charged atmosphere, and he then often passes several hours without
symptoms, relatively well. Later severe symptoms supervene—often rather
suddenly—difficulty of breathing, fits of suffocation, cyanosis, and
copious frothy blood-stained expectoration with symptoms of inflammation
of the bronchial tubes and lungs. These attacks may last a longer or
shorter time, and in severe cases can lead to death; slight cases end in
recovery, without any sequelæ.

In poisoning by nitrous acid fumes, oxygen inhalation, if applied in
time, undoubtedly holds out hope of success, and should always be tried.
Chloroform has been repeatedly recommended as a remedy. Probably its
inhalation produces no actual curative effect, but only an abatement of
the symptoms through the narcosis induced.

Nitric acid (HNO₃) in solution has an irritant corroding action if, when
concentrated, it comes into contact with the skin or mucous membrane.


THE HALOGENS (CHLORINE, BROMINE, IODINE)

Chlorine (Cl) is a yellow-green, pungently smelling gas, Bromine (Br) a
fuming liquid, and Iodine (I) forms crystals which volatilise slightly at
ordinary temperatures.

According to Lehmann’s experiments on animals the effect of chlorine
gas and bromine fumes is completely similar. Lehmann and Binz assume
that chlorine has a twofold effect: (1) narcotic, paralysing the outer
membrane of the brain, and (2) the well-known irritant action upon the
mucous membrane, producing a general catarrh of the air passages, and
inflammation of the lungs; it is, however, only the latter which causes
menace to life. Other writers do not mention the narcotic effect upon
the brain and assume that the halogens when brought into contact with
the mucous membrane are quickly converted into halogen hydrides, and,
as such, produce a corrosive effect. According to Lehmann, even 0·01
per thousand Cl or Br in the air is injurious, even 0·1 per thousand
produces ulceration of the mucous membrane, and one or two hours’
exposure to the poison endangers life. Lehmann has further tested (on
dogs) acclimatisation to chlorine, and finds that after a month the power
of resistance to chlorine appears to be increased about ten times. In a
further series of experiments the same author has proved that even the
smallest quantities of chlorine present in the atmosphere are completely
absorbed in breathing.

Continued or frequent action of chlorine upon the organism produces
symptoms which have been described as chronic chlorine poisoning—such as
anæmia and indigestion, in addition to catarrhal and nervous symptoms.
Further, in factories where chlorine is produced by the electrolytic
process, workers were found to be suffering from the so-called chlorine
rash (first observed by Herxheimer). This skin disease consists in an
inflammation of the glands of the skin, with occasional development of
ulcers and scars. Severe cases are accompanied by digestive disturbance.
Bettmann, Lehmann, and others maintain that it is not caused by chlorine
alone, but by chlorinated tar products, which are formed in the
production of chlorine and hydrochloric acid.

In acute cases of chlorine poisoning oxygen treatment should be tried,
but in any case the patient should have free access to pure air.
Approved remedies are inhalation of soda spray or very dilute ammonia,
or of a vapourised solution of sodium hypochlorite. If the patient is in
great pain, he may be allowed to inhale cocaine solution (0·2 per cent.).

The administration of arsenic (solutio arsenicalis) is recommended,
especially in cases of acne. In general the usual treatment for diseases
of the skin is followed; salicylic acid lotions, sulphur baths, and
sulphur ointments may be made use of.

=Chlorides.=—_Chlorides of Phosphorus_, _Phosphorus-trichloride_ (PCl₃),
and _Phosphorus oxychloride_ (POCl₃), are strong-smelling liquids,
fuming in the air, and when brought into contact with water decomposing
into phosphorous acid and hydrochloric acid. These halogen compounds
of phosphorus have a violently irritant action upon the respiratory
organs and the eyes, in that they decompose on the mucous membrane into
hydrochloric acid and an oxyacid of phosphorus. Inhalation of the fumes
of these compounds causes cough, difficulty of breathing, inflammation of
the respiratory passages, and blood-stained expectoration.

Treatment is similar to that for acid poisoning in general and
hydrochloric acid in particular.

Similar to that of the chlorides of phosphorus is the action of
_chlorides of sulphur_, of which _sulphur monochloride_ (S₂Cl)₂ is of
industrial hygienic importance as it is employed in the vulcanising of
indiarubber. It is a brown, oily, fuming liquid, which, mixed with water
or even in damp air, decomposes into sulphur dioxide and hydrochloric
acid. The fumes of sulphur monochloride have therefore a marked irritant
effect, like that of hydrochloric acid and sulphur dioxide. The action of
sulphur chloride was thoroughly studied by Lehmann. Industrial poisoning
by sulphur chloride is mentioned by Leymann and also in the reports of
the Prussian factory inspectors for 1897. The latter case ended fatally
owing to the ignorance of the would-be rescuers: a workman had spilt
trichloride of phosphorus upon his clothes, and the by-standers, not
knowing its dangerous action when combined with water, poured water on
him.

Treatment is similar to that of poisoning from hydrochloric acid or
sulphur dioxide.

_Chloride of zinc_ (zinc chloride, ZnCl₂) likewise has corroding and
irritant action upon the mucous membrane of the respiratory organs.


AMMONIA

Ammonia (NH₃) is a colourless, pungent-smelling gas which dissolves
to the extent of about 33 per cent. in water. Inhaled, it first
produces violent reflex coughing, then irritation and corrosion of the
mucous membrane of the respiratory organs, and finally death through
suffocation (spasm of the glottis) if exposure to its action has lasted
a sufficiently long time. Microscopic sections exhibit a diphtheritic
appearance of the mucous membrane, and inflammation of the lungs. The
effects upon the central nervous system (irritation of the medulla
and spinal cord) which are peculiar to ammonia compounds need not be
considered, as the corrosion of the respiratory passage is sufficient
alone to cause death. When the action of the gas is less intense, the
patient rallies from the first stage, but often severe symptoms come on
later affecting the lungs.

Lehmann in experiments upon himself could tolerate as much as 0·33 per
thousand NH₃ for thirty minutes; he found in gas works (with fairly
marked odour) hardly more than 0·1 per thousand NH₃ in the atmosphere,
and considers 0·5 per thousand distinct evidence of excess. He found
that he could produce in dogs acclimatisation up to 1·0 per thousand
NH₃ (five times as much as could at first be borne). About 88 per cent.
of the ammonia contained in the air is absorbed in breathing; ammonia
is said to exercise also a reducing action upon the oxygen of the blood
(oxyhæmoglobin).

Chronic poisoning by ammonia can hardly be said to occur. In those who
clean out sewers and drains, the inflammation of the eyes and digestive
disturbance attributed partly to ammonia are probably due more to the
action of sulphur compounds—ammonium sulphide and sulphuretted hydrogen.
Irritation due to solution of ammonia does not come into account in
industrial employment.

As regards treatment, fresh air or administration of oxygen is most
likely to be successful. Inhalation also of very dilute acetic acid
vapour, steam, or spray of sodium carbonate is advocated.


ALKALIS

The alkaline hydroxides (potassium and sodium hydroxide, KOH, NaOH)
have an albumen-dissolving and therefore caustic effect. Industrially
it occurs in the caustic action of concentrated (often hot) lyes upon
the skin or upon the eye—through splashing. Quicklime (CaO) has also a
caustic action, producing inflammation of the skin or eyes (especially in
those engaged in the preparation of mortar).

Under this head comes also the effect upon the respiratory
passages—described by several authors—caused in the production of
artificial manure discussed at length in Part I.

As regards treatment of the irritant effect of alkalis, what has been
said as to corrosives in general applies here (rinsing with water or weak
organic acids), and in inflammation of the eye caused by lime a drop of
castor oil is recommended.


_GROUP: METALS AND METAL-COMPOUNDS_

The various substances of this group differ markedly in their action.
Under this heading come principally chronic metal poisonings,
characterised by a general, often very intense, disturbance of nutrition,
which justifies their delineation as ‘metabolic poisons’; among these
poisons also are included certain others which produce chronic poisoning
accompanied by severe disturbance of the peripheral and central nervous
system.

The corrosive action common to the metal oxides (when acting in a
concentrated condition), attributable to the formation of insoluble
albuminates, need not, in industrial poisoning, be taken so much into
account. The corrosive effect is characteristic only of the compounds,
especially of the acid salts of chromium, which, as an acid-forming
element, may be classed in the preceding group. Disturbance of health
in workmen handling nickel compounds are also ascribed to the corrosive
action of these substances.


LEAD, LEAD COMPOUNDS

Lead poisoning is the most frequent and important chronic industrial
poisoning; the symptoms are very varied and associated with the most
different groups of organs. We shall describe the typical course of a
case of industrial lead poisoning, laying stress, however, on the fact
that numerous cases follow an irregular course, in that special symptoms
or complications of symptoms are in some especially accentuated, while in
others they become less marked or are absent altogether.

A premonitory indication of chronic lead poisoning is a blue line
on the gum, indicated by a slate gray or bluish black edging to the
teeth, the appearance of which is usually accompanied by an unpleasant
sweetish taste in the mouth. The cause of this blue line was for some
time disputed. It is obviously due to the formation and deposit of
sulphide of lead through the action of sulphuretted hydrogen arising from
decomposition in the mouth cavity. At the same time a general feeling of
malaise and weakness often comes on, occasionally accompanied by tremor
of the muscles and disinclination for food, at which stage the sufferer
consults the doctor. Frequently he complains also of pains in the
stomach, not difficult to distinguish from the lead colic to be described
later. Usually the patient already exhibits at this stage general
emaciation and marked pallor.

The blue line was formerly considered a characteristic early indication
of lead poisoning; but it has now been proved that occasionally it is
absent even in severe attacks. But although the blue line may fail as
an ‘initial symptom,’ it will nevertheless be a valuable aid to the
practitioner in the recognition of lead poisoning. It is worth while
to mention the fact that other metallic poisons produce a very similar
‘line,’ especially mercury, also iron and silver (as in the case of
argyria); it has been stated that the blue line can be simulated by
particles of charcoal on the gum. The pallor of the patient at the
commencement of lead poisoning drew attention to the condition of the
blood. The diminution in the amount of hæmoglobin often met with, which
under certain circumstances is accompanied by diminution of the red
blood cells, offers nothing characteristic. On the other hand, structural
changes in the red blood cells—presence of basophil granules in them—are
asserted by a number of writers to be characteristic of the first stages
of lead poisoning. The basophil granules are believed to be due to
regenerative changes in the nucleus. But these changes are also found in
pernicious anæmia, cancer, leucæmia, anæmia, tuberculosis, &c.; also in a
number of poisonings such as phenylhydrazine, dinitrobenzene, corrosive
sublimate, and others; they are therefore the less characteristic of
chronic lead poisoning, as occasionally they cannot be found in actual
lead poisoning, a point upon which I have convinced myself in the case
both of men and animals. Still, the appearance of much basophilia in the
red blood cells is a valuable aid to diagnosis, especially as the method
of staining to demonstrate them is simple.

Other anomalies of the blood observed in lead poisoning may here be
mentioned. Glibert found a striking diminution in the elasticity of the
red blood corpuscles, and experiments I have made point to the fact that
the power of resistance of the red blood corpuscles to chemically acting
hæmolytic agents, such as decinormal soda solution, is considerably
reduced.

The pulse is generally hard and of high tension, especially during the
attacks of colic. Further, cramp of the bloodvessels (also in the retinal
arteries) has been observed. To these functional disturbances in the
circulation are added sometimes definite changes in the vessel wall.
Later, obliterative arteritis comes on (in the brain arteries), and
arteriosclerosis.

The most important symptom of fully developed lead poisoning is colic,
which is usually preceded by the initial symptoms described (especially
the gastric symptoms), but not always so, as occasionally colic sets in
without any warning. The colic pains often set in with marked vehemence.
They radiate from the navel on all sides, even through the whole body;
the abdomen is contracted and as hard as a board. Pressure on the
lower part diminishes the pain somewhat, so that the sufferer often
involuntarily lies flat on his stomach. During the attack the pulse is
often remarkably slow. Constipation occurs, and often does not yield
to purgatives. The attacks last sometimes for hours, occasionally for
days, or the pains can (with remissions) even distress the patient for
weeks. The frequency of attacks is also very variable. Occasionally one
attack follows another, often there are intervals of weeks, even years,
according to the severity of the poisoning and duration of exposure.
If the patient is removed from the injurious action of lead, as a rule
recovery soon ensues.

[Illustration: FIG. 34.—Paralysis of the Ulnar Nerve in Lead Poisoning]

[Illustration: FIG. 34A.—Different Types of Paralysis of the Radial Nerve
in Hungarian Potters poisoned by Lead (_after Chyzer_)]

Often with the colic, or at any rate shortly after it, appear lead
tremor and arthralgia, paroxysmal pain mostly affecting the joints, but
occasionally also the muscles and bones. They are often the precursor of
severe nervous symptoms which affect the peripheral and central nervous
system. In a lead poisoning case running a typical course the predominant
feature is the peripheral motor paralysis of the extensors of the
forearms. Next the muscles supplied by the radial and ulnar nerves are
affected. Often the progress of the paralysis is typical; it begins with
paralysis of the extensor digitorum communis, passes on to the remaining
extensors, then to the abductor muscles of the hand; the supinator
longus and triceps escape. Sometimes the shoulder muscles are attacked;
also paralysis in the region supplied by the facial nerve and of the
lower extremities is observed. It appears plausible that overstrain of
single groups of muscles plays a decisive part; this seems proved by
the fact that paralysis first affects, among right-handed people, the
right hand (especially of painters), but in the case of left-handed,
the left hand; and among children the lower extremities are often
attacked first. Disturbance of sight increasing to amaurosis is often
an indication of severe brain symptoms. The view of some writers that
the cause of the sight disturbance lies in vasomotor influences (cramp
of the bloodvessels) is very probable, and supports the view that the
brain symptoms are entirely due to diseases of the arteries (arteritis).
These symptoms are distinguished by the collective name of saturnine
encephalopathy; they include apoplexy, hemiplegia, epilepsy, delirium,
and mania. The brain symptoms may cause death.

As later symptoms of lead poisoning may be mentioned lead gout and kidney
disease (lead nephritis). The genesis of both these diseases is much
disputed. It seems to be proved that the gout is true gout (with presence
of tophi) and that the contracted kidney is indistinguishable from
ordinary chronic Bright’s disease.

The kidney symptoms suggest that a regular excretion of lead through the
urine takes place which, if it were a fact, would have been an important
aid to diagnosis. But often analysis of urine for presence of lead is
negative. Excretion of lead by the skin is scarcely to be credited,
although occasionally affirmed. Elimination of lead is effected mainly
through the intestines (probably for the most part as sulphide of lead).

All lead compounds more or less are to be regarded as poisonous, although
the intensity of the action depends on the amount absorbed. For this its
solubility in water or in weak acids (hydrochloric acid of the gastric
juice) is the simplest test. According to this acetate of lead, lead
chloride, carbonate of lead (white lead), oxide of lead (lead dross),
minium (red oxide of lead) are relatively the most poisonous. Lead
sulphate and lead iodide are to be regarded as relatively less poisonous,
although by no means innocuous. The least poisonous, if not altogether
innocuous, is sulphide of lead, because it is an insoluble lead compound.

Treatment of lead poisoning ought to aim first and foremost at the
elimination of lead from the body. But unfortunately such attempts have
had little success. Treatment of symptoms is all that for the most
part is possible. Administration of iodide of potassium to assist the
excretion of lead has not been found the success which many anticipated.
This remedy however, can be tried; better results are to be expected
from careful regulation of the bowels by means of purgatives. During
colic administration of opium or morphia may be advisable to relieve pain
and overcome the probable cramp of the intestinal muscles. The cautious
administration of atropine (occasionally with cocaine) also serves
the same purpose. Hot compresses and mustard plasters may be applied,
and liquid diet should be given. Lead cachexia must be treated by
strengthening diet. Electrical treatment for lead paralysis is advocated.
From baths (sulphur baths) nothing more is to be expected than a bracing
effect—elimination of lead through increased diaphoresis is hardly to be
hoped for.


ZINC (ZINC ALLOYS)

Zinc (Zn) melts at 412° C. and distills at about 900° C.; exposed to
the air it burns, when heated, into zinc oxide. Older writers, when
investigating gastric and intestinal diseases and affections of the
nervous system observed in zinc smelters, regarded them as the result of
chronic zinc poisoning; but it may now be accepted as certain that these
symptoms are due to the lead always present in the zinc.

On the other hand so-called _brass-founders’ ague_ may be regarded as
a form of acute industrial zinc poisoning. Brass-founders’ ague occurs
exclusively in brass casters, and not in zinc workers. Sigel and Lehmann
have shown that founders’ ague is also caused by pure zinc if this is
heated so strongly that it burns.

Premonitory symptoms often occur before the onset of the disease; usually
they appear early, soon after casting has begun. The workman has general
malaise accompanied by slight cough, nausea, throat irritation, &c., but
these symptoms mostly disappear, returning again after a few hours with
renewed violence, often in the evening before going to bed. Frequently,
trembling sets in rather suddenly, often accompanied by headache, nausea,
and muscular pains, and soon develops into a pronounced shivering fit,
lasting generally about a quarter of an hour, but in severe cases for
several hours (with intervals). At the same time the breathing is hurried
and the heart’s action quickened (asthma and palpitation). Often the
temperature rises as high as 104° F. The attack ends with profuse
perspiration, and the patient sinks exhausted to sleep, awaking in the
morning generally quite restored or with but slight signs of fatigue;
only rarely is he unable to resume work.

It is noteworthy that some workmen are extraordinarily susceptible to
brass-founders’ ague, and are attacked again and again, while others
remain completely immune, so that idiosyncrasy and immunity both play
a part. Workmen who are susceptible to the disease, yet without marked
disposition (idiosyncrasy) towards it, can become acclimatised to the
poison. Lehmann has succeeded in artificially producing an attack in
a brass-caster who was highly susceptible. The symptoms in him were
the result of work with pure zinc in a burning condition. The proof,
therefore, is clear that brass-founders’ ague is due to zinc, and not, as
some authors have supposed, to copper or the simultaneous action of both
metals. The symptoms are produced through inhalation of zinc oxide, not
zinc fumes.

Lehmann conjectures that brass-founders’ ague may be a secondary fever
due to absorption into the system of the remains of cells in the
respiratory tract that have been killed by the action of the zinc.

The treatment can only be symptomatic; as the attack is so transient,
medical attendance is hardly necessary.


MERCURY, MERCURY COMPOUNDS

Mercury (Hg), on account of its volatility, is classed among industrial
poisons. Although boiling at 360° C. it is volatile even at ordinary
temperature. Industrial mercurial poisoning is caused by the frequent
inhalation of small quantities of vapour, sometimes, but more rarely, of
dust containing mercury, and assumes usually a chronic form.

Industrial mercurial poisoning often begins with inflammation of the
mucous membrane of the mouth and gums. There is increased flow of saliva,
a disagreeable metallic taste in the mouth, and foul breath. This may be
limited to a simple inflammation of the gum, or go on to ulceration with
falling out of teeth, or even to gangrene of the gum and mucous membrane
inside the mouth. Gastric attacks also occur in the early stages;
occasionally, however, they are absent.

The main symptoms of chronic mercurial poisoning are nervous and
psychical derangement, to which in severe cases are added general
disturbance of digestion and loss of strength.

Sometimes, after repeated attacks, more or less severe, a cachectic
condition is induced, showing itself in general emaciation, decrease
of strength, atrophy of the muscles, anæmia, and disturbed digestion,
which—often intensified by some intercurrent disease, such as
tuberculosis—lead to death. Slight cases of mercurialism recover, leaving
no evil results, if the patient is removed in time from the influence of
the poison.

The treatment of chronic mercury poisoning is symptomatic. To allay the
inflammation of the mucous membrane of the mouth the patient should use
a mouth wash of potassium chlorate and peroxide of hydrogen; the general
condition should be raised by strengthening, unstimulating food; for the
nervous symptoms baths and electricity should be tried; and for very
marked erythism and tremor recourse to narcotics may be necessary.

Industrial mercurial poisoning is produced not only by metallic mercury
but also by many compounds, of which industrially the oxides are the
most important. Nitrate of mercury (Hg₂(NO₃)₂) comes into account in the
treatment of fur. Mercury cyanide (HgCy₂) deserves mention, as small
quantities cause mercurial and large quantities cyanogen poisoning.


MANGANESE, MANGANESE COMPOUNDS

Manganese (Mn) or manganese compounds are used industrially in fine
powder; continuous absorption of dust containing manganese produces
chronic manganese poisoning. Instances of such poisoning are not very
numerous; altogether about twenty cases have been described. Recent
publications agree in asserting that only the dust rich in manganese
protoxide is dangerous.

Industrial manganese poisoning runs its course extraordinarily slowly,
and resembles chronic poisoning by other heavy metals, such as lead and
mercury, in that nervous and psychical symptoms, rather than digestive,
are prominent. Sometimes—but not always—the disease is introduced or
accompanied by psychical symptoms, both of excitement and depression
(hilarity, laughing, or depression and weeping). In the course of the
disease nervous disturbances arise, deafness, tingling, paralysis and
paræsthesia, in the arms and legs, giddiness, difficulty of walking,
tremor, increased knee-jerks and difficulty in speech. Often at the same
time swelling of the lower extremities (œdema) and loss of strength
(cachexia, marasmus) come on. Slight cases make a good recovery. An
interesting case of illness is described by Jaksch as manganophobia, in
which the symptoms were simulated, and were brought on solely by the fear
of manganese poisoning.

As regards treatment, electricity, massage, and baths are advocated to
allay the nervous symptoms, as in the case of chronic metal poisoning and
suitable strengthening food.


CHROMIUM, CHROME COMPOUNDS

Chromium trioxide (CrO₃) dissolves in water, forming chromic acid
(H₂CrO₄); of the salts of chromic acid the neutral and acid alkaline
salts concern our inquiry. These are normal and acid sodium or potassium
chromate (K₂CrO₄ and K₂Cr₂O₇). Chromate of lead (PbCrO₄) can cause lead
poisoning.

Poisoning can be produced by dust and by alkaline chromates, the
latter, when hot, giving off steam which, as has been proved, contains
excessively fine chrome particles. Chrome compounds attack especially the
surface of the body, the skin and the mucous membrane.

The bichromate and chromate dust produce ulcers where slight injuries
to the skin already exist. The ulcers develop slowly, and have a
smooth, heaped-up, undermined edge; deep-seated, they can even pierce
to the bone; they heal with great difficulty. Naturally they occur most
frequently on the uncovered parts of the body, especially on the arms
and hands. Characteristic also is an analogous ulceration attacking
the mucous membrane of the nose, from which hardly any chrome worker
(especially if brought into contact with chromate dust) is free.
Perforation and destruction of the cartilaginous septum of the nose is
very common. Ulcers on the mucous membrane at the entrance of the throat
(on tonsils and palate or in the larynx) have been occasionally observed.

Absorption of small quantities of chrome compounds into the body are said
to cause disturbances of digestion of an inflammatory character, and
especially inflammation of the kidneys.

The treatment of chrome ulcers is similar to that of other chronic
ulcers. An antidote for industrial chrome poisoning is not known.


OTHER METALS AND METAL COMPOUNDS

=Nickel Salts.=—Of late years in nickel-plating establishments an
eczematous inflammation of the skin has been described affecting
first of all the hands, and occasionally spreading over the arms and
even the whole body. The skin becomes inflamed, and vesicles appear
on the affected part. Some persons are extraordinarily susceptible
to this disease, others only become so after having worked for years
quite unaffected, and are then obliged to give up their occupation.
Probably the action of nickel salts (especially nickel sulphate) used
in electrolytic baths causes the disease. But it was in fact traced by
several writers to contact with benzene, petroleum, and lime by the
workmen. The simultaneous action of these substances upon the skin
would no doubt encourage its appearance. The application to the skin of
vaseline or cream is recommended. Careful cleanliness and attention to
the skin is on the whole by far the most reliable protection.

[=Nickel carbonyl= (Ni(CO)₄).—Mond, Langer, and Quincke in 1890
discovered that, on passing a current of carbon monoxide over finely
divided (pyrophoric) metallic nickel, a gaseous compound of nickel and
carbon monoxide was formed. When heated to 150° C. the gas decomposes
into its constituents and metallic nickel is deposited.

Nickel carbonyl is a clear, pale straw-coloured liquid, volatilising
at room temperature. It has a peculiar soot-like smell detectable when
present to the extent of about 1 vol. in 2,000,000, while the Bunsen
flame becomes luminous when nickel carbonyl is present in the air to the
extent of 1 vol. in 400,000—two facts of great importance in detecting
escape of the gas in the manufacture of pure nickel by the Mond process.

_Occurrence of poisoning by nickel carbonyl._—At the first introduction
of the process about 1902, before the dangerous properties of the gas had
been sufficiently recognised, some twenty-five men were poisoned, of whom
three died. Poisoning only occurred when, as a result of the breakdown
of the automatic working of the plant, hand labour took the place of
machinery.

This very rare form of poisoning has been very fully investigated by
H. W. Armit (_Journ. of Hygiene_, 1907, p. 526, and 1908, p. 565). The
symptoms in man, he says, were transient headache and giddiness and at
times dyspnœa, quickly passing off on removal to fresh air. After from
twelve to thirty-six hours the dyspnœa returned, cyanosis appeared, and
the temperature began to be raised. Cough with more or less blood-stained
sputum appeared on the second day. The pulse rate became increased, but
not in proportion to the respiratory rate. The heart remained normal.
Delirium of varying types frequently occurred. Death took place in the
fatal cases between the fourth and eleventh days. The chief changes
found post mortem were hæmorrhages in the lungs, œdema of the lungs, and
hæmorrhages in the white matter of the brain, while some doubt exists as
to whether any blood changes were present.

Precisely analogous results were found in experiments on animals
(rabbits, cats, and dogs).

The points Armit investigated experimentally were (1) Is the carbon
monoxide of the compound wholly or partly responsible for the symptoms,
or (2), is nickel carbonyl absorbed as such, or (3), is it the nickel
of the compound which produces the symptoms? His conclusions are that
the poisonous effects of nickel carbonyl are entirely due to the nickel
of the compound. The peculiar toxicity is due to the fact that, being
introduced in a gaseous form, the nickel is deposited as a slightly
soluble compound in a very fine state of subdivision over the immense
area of the respiratory surface. Nickel carbonyl when mixed with air
cannot be absorbed as such by an animal as it becomes split up into the
nickel containing substance (possibly hydrated basic carbonate of nickel)
and carbon monoxide before or soon after reaching the alveoli of the
lungs. The nickel is dissolved from the respiratory surface by the tissue
fluids and is then taken up by the blood. The hæmorrhages found after
death follow as the result of fatty degeneration of the vessel walls
which is the specific pathological change set up by nickel.]

=Copper.=—Symptoms which have been described by some writers as chronic
industrial copper poisoning are probably due to admixtures of other
poisonous metals, especially lead and arsenic. Although some copper
workers, especially those careless of cleanliness, exhibit hair and teeth
coloured by the action of copper compounds (green tinge on hair and edge
of teeth), symptoms of illness traceable to copper are not demonstrable.

_Brass-founders’ fever_, which by some earlier writers was ascribed to
copper or combined copper and zinc action, is traceable to zinc (see
Zinc).

=Ferro-silicon.=—The illnesses due to this are phosphoretted or
arseniuretted hydrogen poisoning (see pp. 191 and 197).

=Silver and Silver Compounds.=—Gradual absorption of small quantities
of a solution of silver may produce industrial argyria, often beginning
with the appearance of a black edge to the gums and darkening of the hair
and nails, followed by black spots on the skin which in severe cases
coalesce, so that the whole or almost the whole surface of the body
becomes black and glossy.

Argyria is due to the absorption of silver compounds into the
circulation, and subsequent deposition of the reduced silver in the body
(liver, kidneys, spinal cord, &c.). The black colouring of the skin is
caused by the action of light.

No interference with health worth mentioning is observed.


_GROUP: ARSENIC, PHOSPHORUS_

The poisons (gradually absorbed) belonging to this group are mainly such
as affect metabolism; they impair the processes essential to metabolism
(in especial the oxidation processes) and cause severe damage to the
cells, through destruction of albumen. The poisons of this group also
have a paralysing effect upon the central nervous system.

Generally speaking the effects produced by the poisons of this group vary
considerably. Among the arsenic compounds arseniuretted hydrogen, which
is supremely a blood poison, must be excluded from the group and included
among the blood poisons.


ARSENIC, OXIDES OF ARSENIC

Pure _metallic arsenic_ (As) is considered innocuous. _Oxides of arsenic_
especially are held to be industrial poisons such as arsenic trioxide
(As₂O₃), the anhydride of arsenious acid (H₃AsO₃), a white powder, which
is known under the name of white arsenic; _arsenic acid_ (H₃AsO₄), which
forms crystals easily soluble in water, and the salts of these acids,
especially copper arsenite, formerly employed in the production of dyes,
and also _arsenic chloride_ (arsenic trichloride, AsCl₃). _Arseniuretted
hydrogen_ will be treated separately as it has a completely different
poisonous effect from that of the oxidic compounds of arsenic. _Arsenic
sulphides_ (realgar, AsS₂, and orpiment, AsS₃) are regarded as innocuous
in consequence of their insolubility in a pure state. But it may be
remarked that arsenic sulphides (sulphur arsenic ores) which are used
industrially, and even metallic arsenic, are to be considered poisonous,
as they contain oxidic arsenic compounds in great quantity.

Chronic arsenical poisoning is caused by gradual absorption through the
respiratory or digestive tracts of small quantities of the oxidic arsenic
compounds either in solution or as dust or fumes.

The disease usually begins with digestive derangement which shows
itself in more or less severe gastric and intestinal catarrh (loss of
appetite, vomiting and diarrhœa); sometimes there are severe affections
of the respiratory tract,—pharyngeal and bronchial catarrhs; often the
illness is accompanied by skin affections of various kinds, rashes,
pustular eczema, loosening of the nails, abscesses, dark pigmentation
of particular parts of the skin, and other symptoms. The nervous
symptoms vary much according to the severity of the disease; first of
all, deafness and feeling of pins and needles, or loss of sensation
(paræsthesia and anæsthesia) of the extremities. Further, rheumatic
joint pains, weakness of the extremities and characteristic symptoms of
paralysis occur, with accompanying atrophy of the muscles, and gradual
loss of energy leading to total incapacity for work. Severe cases end in
general exhaustion and loss of strength, with signs of severe injury to
the central nervous system, such as epileptic fits, mental hebetude, &c.


PHOSPHORUS

_Phosphorus_ (P) is polymorphic; red (amorphous) phosphorus is innocuous,
while white or yellow is poisonous. Phosphorus at various stages of
oxidation is little if at all poisonous. White phosphorus is volatile
and fumes in the air—the fumes consisting of phosphorus, phosphoric and
phosphorous acids.

Chronic industrial phosphorus poisoning is produced by continued
inhalation of the fumes of white phosphorus resulting in inflammation
of the periosteum of the bone, with which necrosis and formation of new
bone are associated. It attacks especially the lower jawbone (ossifying
periostitis). The inflammation begins with increased flow of saliva,
painful swelling of the gums, which, as it increases, brings about the
death of the jawbone (necrosis, phosphorus necrosis). This becomes
covered again with newly formed bone substance from the periosteum. The
process ends with the formation of a fistula (a passage filled with pus),
which discharges outwards, and through which the dead bone (sequestrum)
is eventually cast off. Occasionally the process attacks the upper jaw,
rarely other bones.

With these characteristic symptoms of phosphorus necrosis, derangement of
nutrition together with anæmia, indigestion and bronchial catarrh, may
be associated. Further, a general brittleness of the bones (fragilitas
ossium) is observed with the result that the long bones of the leg or arm
sometimes break at relatively small exertion of force; such cases from
Bohemia came lately under my notice.

Some authorities regard caries of the teeth as the pre-disposing cause of
phosphorus necrosis; according to this view the carious teeth constitute
the means of entrance for the poison. Opposed to this so-called ‘local’
theory is the view that chronic phosphorus poisoning is a ‘general’ one.
The truth may lie midway. On the one hand phosphorus necrosis probably
arises partly from the general poisonous action of the phosphorus, and on
the other from local inflammation which leads to the occurrence of local
symptoms. The general symptoms of chronic phosphorus poisoning described
above support this view, especially the effect observed on the bones of
the skeleton. This view is also strengthened by the fact that workmen
with perfectly sound teeth, who had been exposed to phosphorus fumes for
many years, were attacked by necrosis only when traumatic inflammation
produced by chance injury was set up.

The treatment of phosphorus necrosis is surgical. Formerly the treatment
recommended was to wait for formation of new bone and exfoliation of the
dead bone (expectant treatment); the necrosed portions of bone were then
extracted through the fistula. Recently early operative interference has
succeeded in preserving the periosteum which enabled the new bone to form.


Phosphoretted Hydrogen

Industrial poisoning by gaseous phosphoretted hydrogen (PH₃) calls for
attention in connection with the preparation and employment of calcium
carbide (acetylene) and also of ferro-silicon.

Phosphoretted hydrogen is a dangerous poison. Even 0·025 per cent. in
the air is harmful to animals after a time; 0·2 per cent. PH₃ in the air
quickly causes death.

The poison produces changes in the lungs, though without injuring the
respiratory passages by corrosion, and finally has a paralysing effect
upon the central nervous system. It has no effect upon the blood. An
autopsy on a person who has died of phosphoretted hydrogen poisoning
reveals as a rule no characteristic sign, except centres of inflammation
in the lungs.

The symptoms of phosphoretted hydrogen poisoning are—difficulty of
breathing, cough, fainting fits, noises in the ears, and nausea;
in severe cases coma and death. Slight cases soon recover without
after-effects.


_GROUP: SULPHURETTED HYDROGEN, CARBON BISULPHIDE, AND CYANOGEN (NERVE
POISONS)_

In this group are comprised industrial poisons the principal effect of
which is upon the nervous system, especially the central nervous system.
The chemical composition of the separate members of the group differs
much.


SULPHURETTED HYDROGEN

Industrial poisoning by pure sulphuretted hydrogen (SH₂), the well-known
colourless, nauseous-smelling gas, occurs comparatively rarely. Poisoning
is generally acute, but chronic illness in workers has been traced back
to inhalation of the gas.

This poison exerts a paralysing action upon the central nervous system
and is slightly irritating to the mucous membranes and respiratory organs.

Its action can be described as follows: When absorbed into the blood
union of the poison with the alkaline constituents takes place with
formation of an alkaline sulphide. Presence of only slight quantities
of sulphuretted hydrogen in the air acts injuriously. Lehmann has shown
that about 0·15 to 0·2 per thousand sulphuretted hydrogen is not without
effect, and that prolonged inhalation of 0·5 per thousand becomes
dangerous. Continued exposure to the poison seems only to increase
susceptibility to its action. An almost complete absorption of the whole
of the sulphuretted hydrogen present in the air breathed takes place.

Continued inhalation of small quantities of sulphuretted hydrogen
produces irritation of the mucous membrane, cough, and lacrymation;
headache, giddiness, nausea, and mental dulness soon ensue; occasionally
also symptoms of intestinal catarrh follow; if at this stage—or after
a longer exposure to the action of a smaller amount—the patient is
withdrawn from its further influence, there still continue for some time
symptoms of irritation of the mucous membrane (such as inflammation of
the conjunctiva and of the respiratory passages).

Further exposure or absorption of greater amounts induces general
discomfort and passes on to a second stage of convulsions and delirium.

Inhalation of a large dose of sulphuretted hydrogen causes almost
instantaneous death; the affected person falls dead—often without
a sound—as if struck by a blow; occasionally a short stage of
unconsciousness, with symptoms of suffocation, precede death.

This acute form often occurs, especially in acute sewer gas poisoning.
Besides this, a sub-acute form of sewer gas poisoning is recognised
which is attributable, in part at least, to the action of sulphuretted
hydrogen, the prominent symptoms being irritation of the mucous membranes
and of the intestinal canal. In other severe cases symptoms of the
central nervous system preponderate (headache, giddiness, and delirium).
These forms of poisoning can be caused not only by sulphuretted hydrogen,
but also by other poisonous gases which are found in drains or sewers.

As regards treatment, continued inhalation of oxygen, supported by
artificial respiration, is often, in serious cases, effective. In severe
poisonings also saline injections and bleeding may be advocated. Other
symptoms (catarrh, &c.) must be treated symptomatically.


CARBON BISULPHIDE

Pure carbon bisulphide (CS₂) is a colourless, peculiar-smelling liquid
which boils at 46° C.

As Lehmann has shown, even 1·5 to 3·0 mg. CS₂ per litre of air produces
distress—with acute symptoms of poisoning (congestion, giddiness,
sickness, &c.).

Industrial carbon bisulphide poisoning is, however, chronic in nature and
induced by continuous inhalation of small quantities of the fumes. To
understand the action of carbon bisulphide, its capacity for dissolving
fats and fatty substances must be taken into account. Its injurious
effect extends to the nerve tissues (central and peripheral nervous
system) and the glandular tissues.

Throughout chronic industrial carbon bisulphide poisoning, which has
been described fully by Delpech, Laudenheimer, and others, nervous and
psychical symptoms predominate, together with severe chronic digestive
derangement.

The patient after exposure for some time suffers from violent headache,
giddiness, and sickness; he has sensations of cold, pains in the
limbs, a feeling of ‘needles and pins,’ and itching in different parts
of the body. Gradually a condition of general excitement develops.
Sleeplessness, cramps, and palpitation set in. At the same time the
nervous system becomes involved—hypersensitiveness, loss of sensation
or complete numbness of some parts of the skin, diminution of muscular
power, disturbances of movement, twitching, violent trembling, wasting
of the muscles, and paralysis; the sight also is sometimes affected.
The stage of excitement, in which the patient often becomes strikingly
loquacious without cause, passes gradually, as the nervous symptoms
develop, into the stage of depression; sometimes this takes weeks and
months; excitement and gaiety give place to deep depression; other
symptoms appear—weakness of memory, mental dulness, and difficulty in
speaking. The powers of sensation become affected, paralysis increases,
and digestive disturbances, anæmia, and general loss of strength are
manifest. Occasionally definite mental disease (psychosis, mania,
melancholia, dementia, &c.) develops.

Certain cases of chronic carbon bisulphide poisoning in indiarubber
workers have come under my notice, and some remarks concerning them
may be of interest. The characteristic symptoms are essentially as
follows: the invalid appears in the consulting-room in a bent position,
leaning upon a stick with head and hands shaking. The gait is clumsy
(spastic-paralysis) so that the patient ‘steps’ rather than walks. When
seated, the tremor ceases to some extent, but in purposive movements
increases rapidly, involving the whole body, so that an exact systematic
examination becomes impossible, and the invalid sinks back into the
chair exhausted and bathed in perspiration. He complains of cold in
the extremities. He looks pale; the skin of the upper extremities is
totally without feeling, as also is the upper part of the feet; the skin
of the head is hypersensitive; the muscular strength of the arms is
almost lost; testing the strength brings on marked shaking, followed by
a fainting-fit caused by exhaustion. The extremities of the patient are
cyanotic (livid); the knee jerks are exaggerated. The patient suffers
from indigestion, constipation, headache, and giddiness; he is irritable,
and depressed; his memory is weak; mental derangement cannot be proved.

Chronic carbon bisulphide poisoning is rarely fatal. Slight cases end in
recovery after more or less long continuance; in severe cases improvement
occasionally takes place, but serious nervous disturbance (paralysis,
weakness of the muscles, deterioration of intellect) usually persists.

Treatment is symptomatic, aiming especially at relieving the nervous
symptoms and improving the state of nutrition. If psychical disturbances
are prominent, treatment in an institution is necessary.


CYANOGEN AND CYANOGEN COMPOUNDS (CYANOGEN GAS, PRUSSIC ACID, CYANIDES)

Industrial cyanogen poisoning is not frequent. _Cyanogen gas_ (C₂N₂,
existing in small quantities in furnace gas, illuminating gas, and other
kinds of gas) and especially _hydrocyanic acid_ (CNH, prussic acid) are
considered industrial poisons; the latter is a very unstable, colourless,
pungent-smelling liquid, boiling at 27° C. Among the cyanides employed
industrially and having an effect similar to that of prussic acid must be
mentioned _cyanide of potassium_ and _cyanide of sodium_ (KCN and NaCN),
_cyanide of silver_ (AgCN) and _cyanide of mercury_ (Hg[CN]₂).

Cyanogen and cyanogen compounds are extraordinarily powerful poisons. The
minimum dose lies, as Lehmann has proved by experiments on animals, at
about 0·05 per thousand of hydrocyanic acid in the atmosphere breathed;
1-5 mg. per kg. weight is fatal to animals; to man about 60 mg. would be
fatal.

The poisonous action of cyanogen and cyanogen compounds depends upon
their power of preventing absorption of oxygen from the blood by the
tissues with the result that the venous blood flowing to the heart
retains the bright red colour which otherwise only arterial blood
exhibits. This effect is due to cessation of the gaseous exchange in the
body, and results in tissue suffocation. At the same time these poisons
have at first an exciting and then a paralysing effect upon the central
nervous system. In severe poisoning the nerve effect is masked by the
effect upon the exchange of gases in the blood, since this quickly leads
to death.

Most of the cases of industrial poisoning under this heading result from
inhalation; absorption of liquid cyanogen compounds through the skin can
rarely come into consideration.

If large quantities of hydrocyanic acid have been inhaled, death ensues
very quickly. The person affected falls down suddenly, breathes with
difficulty, the pulse soon becomes imperceptible, and after a more or
less long stage of deep unconsciousness (coma) life becomes extinct.

In slight cases of poisoning the patient feels a sensation of irritation
in the throat, giddiness, sickness, and difficulty in breathing;
occasionally such disturbances persist for some time.

Some writers have described symptoms in workers manipulating prussic
acid and cyanides, which they believe to be due to chronic prussic
acid poisoning. Complaint is made of oppression of the chest, throat
irritation, giddiness, difficulty in breathing, palpitation, hebetude,
exhaustion, and nausea and vomiting; in certain instances the attack,
aggravated by exhaustion and weakness, culminates in death. It is a
question whether such poisonings are chronic in the true sense of the
word. In view of the mode of action of hydrocyanic acid, such cases
of sickness should rather be accounted acute or sub-acute poisonings
through repeated action of small quantities of the poison.

It may be mentioned that in persons working with alkaline cyanides
(especially in electro-plating) skin affections occasionally occur; these
are traceable to the caustic effect of alkaline cyanides.

Treatment by oxygen inhalation with simultaneous artificial respiration
holds out most prospect of success. This holds good for acute poisoning
by the other poisons belonging to this group. Besides this, saline
injections and bleeding are recommended, and also the administration of
an infusion of sodium thiosulphate solution.


_GROUP: ARSENIURETTED HYDROGEN AND CARBONIC OXIDE (BLOOD POISONS)_

Included in this group, as in the former one, are substances chemically
very different from each other, but of which the action is especially
on the blood. Besides this common effect, these substances also produce
various other effects, such as local irritation, effect on the nervous
system, &c. The industrial blood poisons, which according to their
chemical constitution are classed among the aliphatic and the aromatic
series of organic compounds, will, for the sake of clearness, be
discussed in the following chapters.


ARSENIURETTED HYDROGEN

Acute arseniuretted hydrogen poisoning, produced by inhalation of
relatively very small quantities of arseniuretted hydrogen gas (AsH₃)
is in most cases industrial in origin. The absorption of an amount
corresponding to about 0·01 mg. arsenic suffices to produce severe
poisoning symptoms. The poisonous effect results chiefly from action upon
the red blood corpuscles, which are dissolved (hæmolysis). Arseniuretted
hydrogen is therefore a genuine blood poison. The effect upon the
blood, if not immediately fatal to life, is to cause the dissolved
blood-colouring matter to pass into the tissues where, though some is
deposited, most goes to, and acts injuriously on, the organs, especially
the liver, spleen, and kidneys. In cases running at once a fatal course,
the impoverishment of the blood caused by the lack of colouring matter
necessary to internal respiration produces tissue suffocation, which is
therefore the primary cause of death. In cases not immediately fatal, the
injury to the functions of the organs alluded to (for instance, cessation
of the functions of the kidneys, &c.) may lead to death secondarily.

Symptoms of the disease appear often only some time after the poisoning
has set in, and begin with general malaise, sickness, collapse, fainting
fits, and difficulty of breathing; after some hours the characteristic
signs follow—the urine becomes dark red to black, containing quantities
of blood colouring matter and dissolved constituents of the blood, and
later also bile colouring matter, so that a coppery jaundice comes on if
the illness is prolonged. The region of the liver, spleen, and kidneys
is painful. Severe cases often end fatally during the first stage of
the illness, more rarely later, with increased difficulty of breathing;
sometimes death occurs after a preceding comatose stage marked by
convulsions and delirium. In slighter poisoning cases the symptoms abate
in a few days and recovery follows.

The treatment of arseniuretted hydrogen poisoning is similar to that
adopted in the case of all other blood poisonings: in addition, if
possible, direct transfusion of blood from the artery of the giver into
the vein of the receiver, liquid nourishment, saline injections, and,
above all, prolonged oxygen inhalation.


CARBONIC OXIDE (CO)

Carbonic oxide (CO) is a colourless, odourless gas which frequently
causes both acute and, it is said, chronic industrial poisoning.

Carbonic oxide is a very poisonous gas; even as little as 0·5 per
thousand in the atmosphere breathed has a poisonous effect; about 2-3 per
thousand can be dangerous to life.

Its poisonous effect results from its power of combining with the
blood-colouring matter or hæmoglobin to form carboxy-hæmoglobin; the
affinity of carbonic oxide for the hæmoglobin of the blood is more than
200 times greater than that of oxygen, so that, however small the amount
of carbonic oxide in the air, it is inevitably absorbed by the blood and
retained. The blood so altered, assumes a cherry-red colour, is unable to
effect the necessary exchange of gases for internal respiration, and in
consequence of the lack of oxygen suffocation ensues.

Without doubt, however, carbonic oxide has also an immediate effect
upon the central nervous system (first excitation, followed quickly
by paralysis). It is maintained also that besides the action upon the
hæmoglobin it favours coagulation of the blood through the disintegration
of the blood corpuscles. The last-mentioned action is thought to account
for the sequelæ of carbonic oxide poisoning, but they can also naturally
be accounted for by the direct effect of the poison.

Onset of symptoms is very sudden if a large quantity of pure carbonic
oxide is inhaled. The affected person immediately falls down unconscious
and succumbs after drawing a few breaths with difficulty.

In less acute cases the illness begins with premonitory symptoms,
generally headache, sickness, giddiness, sleepiness, though in cases
of fairly rapid absorption these are absent, and are naturally absent
also when the poisoning creeps upon the affected persons while asleep,
as occasionally happens in cabins, &c., in factories. If the poisoning
continues, increasing mental dulness, accompanied by nausea and vomiting,
leads sometimes to a short stage of seemingly drunken excitement, which
preludes deep unconsciousness during which there is often a convulsive
stage, followed by complete loss both of sensation and of reflex action;
the breathing becomes shallow and intermittent, the pulse small and
irregular, and finally death ensues. Occasionally in the stage of
unconsciousness, death is hastened by entrance of vomited matter into the
respiratory passages. Bright red patches are seen on the body after death.

If persons affected by severe carbonic oxide poisoning are withdrawn
from the poisonous atmosphere after having reached the stage of
unconsciousness, they may recover, but often with difficulty; not
infrequently—in spite of suitable treatment—death occurs some
considerable time later from the symptoms described above. Still, in many
cases, under the influence of right treatment, gradual recovery has been
brought about, even after long unconsciousness accompanied by repeated
convulsions. In the rescued the symptoms described as characteristic of
the first stage often continue for at least a day. Further, they are
liable to a number of serious after effects, such as severe inflammation
of the lungs due to infection by the entrance of vomited matter into the
air passages, skin affections (rashes), and especially severe nervous and
mental affections. Frequently these develop from centres of softening
in the brain or from inflammation of the peripheral nerves (neuritis);
occasionally the poisoning may really only be the predisposing cause for
the outbreak of an existing psychical disease. It is not our task to
enumerate all the extremely varied disturbances which are observed after
carbonic acid gas poisoning. Neuralgias and paralyses have been described
as associated with the peripheral nerve symptoms over areas supplied
by different nerves; various forms of diseases of the brain and spinal
cord (poliomyelitis, paralysis, sclerosis, &c.); and finally a series of
psychoses (neurasthenia, melancholia, mania, &c.), occasionally passing
into dementia and imbecility. Glycosuria (sugar in the urine) has also
been noted as a sequela.

Chronic carbonic oxide poisoning, arising from continued inhalation of
small quantities of the gas, sets in usually with symptoms similar to
those of acute carbonic oxide poisoning; if the worker continues exposed
to danger, severe symptoms may arise which point to marked alteration of
the blood and later also of the digestion and bodily functions. Under
certain circumstances severe nervous and mental affections are said
to occur similar to those which we have mentioned as sequelæ of acute
carbonic oxide poisoning (convulsions, disturbances of mental activity,
symptoms which resemble progressive muscular atrophy, &c.).

In acute carbonic oxide poisoning oxygen inhalation indefatigably
continued and supported by artificial respiration is often successful.
The serious danger from this form of poisoning renders it very necessary
that in all premises where there is risk provision should be made for
the administration of oxygen. The sequelæ can of course only be treated
symptomatically.


OXYCHLORIDE OF CARBON (PHOSGENE)

Oxychloride of carbon (COCl₂), also called phosgene, is, at the ordinary
temperature, a colourless gas with a disagreeable smell. This decomposes
in moist air into carbonic oxide, hydrochloric acid, or chlorine, and
produces a strongly irritant local effect upon the mucous membranes.
Industrial poisoning by phosgene is characterised by great difficulty
in breathing and inflammation of the respiratory tract (bronchitis and
bloodstained expectoration).

Several cases have been treated successfully by oxygen inhalation.


NICKEL CARBONYL

The effects of nickel carbonyl are described on pp. 186-8.


CARBONIC ACID

Carbonic acid (CO₂), a colourless gas, is heavier than air (specific
weight, 1·526), and therefore, wherever it collects, sinks to the ground.
Carbonic acid is only very slightly poisonous; about 10 per cent.
carbonic acid in the air causes asphyxia. The extinguishing of a candle
flame will serve as an indication that the amount of carbonic acid in
the atmosphere has reached this point. Cases of industrial carbonic acid
asphyxia are sudden; they do not occur frequently.

The gradual action of the gas when mixed with air produces first a
tingling sensation on the surface of the body, reddening of the face,
irritation of the mucous membrane and the respiratory organs, after
which succeed difficulty in breathing, palpitation, fainting, and
unconsciousness.

Sudden and fatal poisoning occurs industrially. Upon entering places
filled with carbonic acid gas the affected person falls down dead almost
immediately. These are cases of asphyxia, in which the lack of oxygen
certainly plays the greatest part. If those affected by acute carbonic
acid poisoning are removed in time out of the dangerous atmosphere they
usually recover quickly.

Oxygen inhalations and artificial respiration are to be applied in
severer cases. There are no sequelæ.


_GROUP: HYDROCARBONS OF THE ALIPHATIC AND AROMATIC SERIES AND THEIR
HALOGEN AND HYDROXYL SUBSTITUTION PRODUCTS_

The industrial poisons comprised in this group have as their principal
general effect injurious action upon the functions of the central
nervous system (paralysis or causing excitation) which is prominent in
most of the cases of industrial poisoning caused by these substances.
This effect is most marked in the case of the readily volatile (low
boiling) hydrocarbons, while those less volatile and boiling at a higher
temperature often have collateral effects (such as local irritation).
The characteristic poisonous effect caused by the chlorine and
hydroxyl-substitution products (chloroform and alcohol group) is also
mainly on the central nervous system (narcosis).


HYDROCARBONS OF MINERAL OIL

BENZINE, LIGROINE, PETROLEUM, PARAFFIN, VASELINE

_Mineral oil_ (crude petroleum) has, according to its origin, differing
composition. Thus in American mineral oil hydrocarbons of the methane
series preponderate; in the Russian, hydrocarbons of the aromatic series.
Reference has been made in Part I. to this point, as well as to the
separation of crude petroleum into its different fractions.

The injury to health produced by crude petroleum and its derivatives is
of two kinds. Direct contact with liquid petroleum and the semi-liquid
and solid deposit after distillation (paraffin) cause local injury to the
skin. Inhalation of the volatile constituents of raw petroleum causes
symptoms affecting mainly the central nervous system. They have moreover
a markedly irritating effect upon the mucous membrane of the respiratory
organs. These substances clearly exhibit the characteristic we have
referred to, namely, that the hydrocarbons boiling at low temperature act
as nerve poisons, whereas those boiling at a higher temperature produce a
local irritant effect.

The skin affections take the form of inflammation of the hair follicles
(acne), eruptions with characteristic formation of vesicles, and
pimples and pustules which precede the deep-seated formation of ulcers,
abscesses, &c.

In paraffin workers the acne-like skin inflammations are known as
‘paraffin eczema.’ They develop sometimes into cancer of the skin (warty
and epitheliomatous growths).

In the general poisoning produced by inhalation of petroleum fumes the
effect upon the central nervous system is all the more plainly and
clearly marked when the irritant effect of the hydrocarbons boiling at
higher temperature is slight or absent; that is, in the case of poisoning
which arises solely from industrial products of low boiling hydrocarbons;
among these benzine is included.

Acute poisoning from inhalation of benzine fumes begins with headache,
sickness, and attacks of giddiness resembling alcoholic intoxication. If
very much has been inhaled, the patient quickly becomes unconscious, with
occasionally muscular tremors, convulsions, difficulty in breathing, and
cyanosis.

In cases of poisoning by inhalation of fumes of crude petroleum, these
symptoms may be complicated by coughing, intense inflammation of the
mucous membrane of the respiratory organs—congestion, bronchitis,
bloodstained expectoration, and inflammation of the lungs. In workers
who frequently remain long in an atmosphere filled with benzine fumes,
further symptoms of chronic benzine poisoning show themselves—mental
hebetude, pains in the limbs, trembling, weakness of the muscles, and
other disturbances of the nervous system; in such cases these may really
be signs of continued attacks of acute or sub-acute poisoning; many
benzine workers are anæmic.

The treatment of acute benzine poisoning consists in oxygen inhalation,
with simultaneous artificial respiration. Treatment of chronic
derangement of health is symptomatic.


HYDROCARBONS OF THE AROMATIC SERIES

BENZENE AND ITS HOMOLOGUES

_Benzene_ (C₆H₆) is a characteristically smelling (aromatic) liquid which
boils at 80·5° C. Acute benzene poisoning, which plays an important part
as an industrial poisoning, is caused by inhalation of benzene fumes. The
various kinds of benzol used commercially contain, besides benzene, alkyl
benzenes, especially _toluene_ (methylbenzene, C₆H₅.CH₃, boiling-point
111° C.); _xylene_ (dimethylbenzene, C₆H₄[CH₃]₂, boiling-point 140°
C.); _pseudocumene_ and _mesitylene_ (tri-methylbenzene, C₆H₃[CH₃]₃,
boiling-point 169° or 163° C.); the regular presence of _thiophene_
(C₄H₄S, boiling-point 84° C.) in commercial benzol must also be taken
into account. Industrial benzol poisoning arises, therefore, as a rule,
not from the action of pure benzene vapour, but from fumes which contain
a mixture of the compounds mentioned.

The course run by industrial benzol poisoning is often very acute, if
large quantities are inhaled—death occurring suddenly, after a short
illness with symptoms of vertigo. Gradual inhalation of lesser quantities
gives rise to headache, giddiness, malaise, then twitchings appear
which develop into convulsions, and lastly unconsciousness. In order to
ascertain in what manner the various substances contained in commercial
benzol share in the poisonous effect, experimental research seemed to me
to be indispensable, especially as published statements so far gave no
accurate data.

Two cases of industrial benzol poisoning have given rise to close
experimental research upon the poisonous nature of benzene.

Lewin undertook experiments on animals; which he confined under bells
and caused to inhale fumes of chemically pure and impure benzene. He
mentions that even at comparatively low concentration poisoning results,
and indeed more readily and certainly from the action of impure than pure
benzene. Lewin found that when air was made to flow slowly first through
benzene and then into the bell, symptoms of paralysis, convulsions,
and unconsciousness showed themselves in from four to six minutes.
After-effects by this means could not be observed. Lewin maintains,
however, that in man even slight acute action of benzene can be followed
by after-effects (giddiness, sickness, headache, distress in breathing,
and oppression of the heart).

Santesson made researches upon the poisonous action of benzene in
connection with occurrence of certain cases of poisoning through ‘impure
benzol’ (coal-tar benzene) in a rubber tyre factory. In the factory
mentioned nine young women were poisoned, of whom four died. The symptoms
shown were lassitude, anæmia, giddiness, headache, vomiting, and fever.
Post mortem, hæmorrhages and fatty degeneration of the endothelium of the
bloodvessels and various organs were found. Experimental research showed
that commercial benzol and chemically pure benzene had the same effect.
Santesson did not succeed in his experiments on animals in producing
chronic poisoning by inhalation of benzine and of benzene fumes (which
two completely different poisons he does not distinguish strictly from
each other, as is the case, unfortunately, with many other writers). My
experimental researches upon the poisonous effect of pure benzene, pure
toluene, cumene, thiophene, and the most important kinds of commercial
benzol gave the following results:

For rabbits the limit of toxicity is a proportion of 0·015 to 0·016 per
thousand pure benzene in the air, that is 0·015 to 0·016 c.c. benzene
vapour per litre of air.

A concentration of 0·056-0·057 per thousand pure benzene in the air
causes in rabbits at once—after one minute—twitching of the muscles;
after eight minutes, convulsions; after ten minutes, deep narcosis; and
after twenty-five minutes, coma. If the animal is taken out of the bell
in time, even if it has shown marked symptoms, it recovers very quickly
(in two to ten minutes) without manifesting any after effects. Even in
animals repeatedly exposed to the poison sequelæ were not observed.

Dogs are somewhat more susceptible to pure benzene than rabbits; 0·024
per thousand causes after ten minutes severe convulsions, which after
twenty minutes become continuous; 0·042 per thousand kills after twenty
minutes (sudden death in a state of tetanus).

Cats are less sensitive than dogs and more sensitive than rabbits;
0·03-0·04 per thousand causes after ten minutes attacks of cramp and,
after twenty minutes, convulsions; 0·05 per thousand at once brings on
poisoning symptoms. As regards the character of the symptoms (cramps,
convulsions, quick recovery, no after effects) the above statements apply
to all three kinds of animals (rabbit, dog, and cat).

Chloral hydrate completely checks the convulsions and enables animals to
tolerate higher concentrations of benzene for a longer time.

Benzene is thus to be counted among nerve irritant poisons. The
convulsions are probably provoked by excitement of the motor centres in
the brain.

In view of the fact that thiophene in a concentration of 0·03-0·05 per
thousand in the air was borne by animals for an hour without producing
any symptoms of poisoning, the proportion of thiophene in commercial
benzol must be looked upon as practically non-injurious.

The so-called 90 _benzol_—a commercial benzol of which 90 per cent.
distils at 100° C.—has naturally a somewhat weaker action, although, in
respect of the poisoning symptoms produced, it is similar to that of pure
benzene.

_Pure toluene_ (boiling-point 111° C.) and purified toluol (commercial
product, boiling-point 109°-112° C.) produce, when inhaled, gradually
increasing narcosis in the three kinds of animals referred to; they
produce no symptoms of convulsions or spasms.

After the animals have been taken out of the bell, recovery is not so
rapid as after benzine inhalation, but takes from half an hour to one
hour. In rabbits and cats 0·046-0·05 per thousand produces after fifteen
minutes staggering and paresis; after thirty minutes deep narcosis. The
dog is again somewhat more susceptible, as little as 0·034 per thousand
causing these symptoms in the same time.

‘Purified toluol’ (commercial product) acts somewhat less rapidly
than pure toluene, but this small difference in effect need hardly be
considered.

Other poisons were also investigated:—

_Solvent naphtha I_, a commercial product, of which 90 per cent.
comes over at 160° C.; it contains little toluene, chiefly xylene,
pseudocumene, and cumene.

_Solvent naphtha II_, of which 90 per cent. comes over at 175° C, it
contains besides xylene, chiefly pseudocumene, mesitylene, cumene, &c.

The fumes of solvent naphtha I cause, when inhaled by rabbits, dogs, and
cats, gradual narcosis, although not nearly so quickly as toluene at
similar concentrations; recovery usually takes over an hour after the
deeply narcotised animals have been removed from the bell. Rabbits and
cats are affected in about equal degree. The dog is the more sensitive.
Rabbits and cats can tolerate about 0·012-0·013 per thousand of the
fumes of solvent naphtha I in the atmosphere for a long time without any
symptoms. Only after breathing for fifty minutes air containing 0·0536
per thousand do they become narcotised. In the dog 0·036 per thousand
causes narcosis only after thirty minutes.

With the fumes of solvent naphtha II I could not affect rabbits at all.
The cat also, in spite of long inhalation of the heavy fumes, showed no
marked symptoms of poisoning. In the dog gradual narcosis came about only
after an hour’s inhalation of 0·048 per thousand.

The fumes of pure _xylene_ caused narcosis in rabbits after forty
minutes’ inhalation of 0·05 per thousand in the atmosphere; after being
taken out of the bell the animals recovered slowly (after half an hour to
one hour).

_Cumene_ causes no symptoms after one hour’s inhalation in a
concentration of 0·06 to 0·07 per thousand. This explains the effects of
solvent naphtha I (in which xylene preponderates) and solvent naphtha II
(in which pseudocumene, cumene, &c., preponderate). After effects were
not observed.

Benzol and toluol fumes, and particularly those of solvent naphtha,
exercise a distinctly irritant effect upon the mucous membrane, which,
however, passes off without after effects.

Pure benzene, therefore, proved the most poisonous of the substances
under investigation. When inhaled its effect (convulsions, with quick
recovery) differs essentially from that of toluene, solvent naphtha,
xylene, and cumene (gradual narcosis, slow recovery). The fumes of the
various kinds of commercial benzol (solvent naphtha) boiling at a higher
temperature are practically non-poisonous (solvent naphtha II). Pure
benzene fumes are, however poisonous, even in very small quantities in
the air. The limit for animals lies at 0·015-0·016 per thousand.

Lehmann has shown in a recent work that man, exposed to a mixture of
benzene and air, absorbs 80 per cent. of the benzene.

Treatment of acute industrial benzene poisoning consists in severe cases
of artificial respiration, with simultaneous administration of oxygen; in
slight cases it is sufficient to bring the patient into fresh air.

_Naphthalene._—Naphthalene, which is insoluble in water, has irritant
effect upon the mucous membrane and upon the skin when brought into
contact with it.

Long continuance in an atmosphere containing naphthalene as dust or fumes
causes headache, nausea, giddiness, &c.


HALOGEN SUBSTITUTION PRODUCTS

ALIPHATIC SERIES (NARCOTIC POISONS)

The halogen substitution products of the aliphatic series are not of
much account as industrial poisons. They have generally a narcotic
effect, that is, a paralysing effect upon the central nervous system,
usually preceded by a short stage of excitement. This effect shows itself
typically on inhalation of chloroform (methanetrichloride, CHCl₃), which
however plays no part as an industrial poison. The narcotic effect of
the other alkyl chlorides is less than that of chloroform. With carbon
tetrachloride (CCl₄) the narcotic effect is only half that of chloroform;
it causes, however, a more violent excitation; inhaling the fumes brings
on nausea, coughing, sickness, headache, &c.

_Methylchloride_ (CH₃Cl) has a less narcotising effect. On the other hand
it has a stronger local irritant action, which is indeed present also in
chloroform, though not so apparent. This gas, as is well known, is used
as a local anæsthetic in medicine.

Pure _methylene chloride_ (CH₂Cl₂) similarly is much less powerful than
chloroform. Severe poisoning, alleged to have resulted from methylene
chloride was caused by a mixture, called indeed methylene chloride, but
composed of methylalcohol and chloroform.

Of the remaining halogen substitution products of methane, _methyl
bromide_ (CH₃Br) and _methyl iodide_ (CH₃I) have given rise to industrial
poisoning.

These poisons also act in the same way as the alkyl chlorides, but the
excitement accompanying the narcosis is more marked—so far as the scanty
observations allow conclusions to be drawn. The symptoms first show
themselves in sickness, giddiness, hebetude, slowing of respiratory
movements and of the heart’s action; convulsions or delirium ensue.

Treatment consists in artificial respiration or promotion of breathing
by a plentiful supply of fresh air or oxygen; in pronounced narcosis
stimulating remedies should be applied.


BENZENE SERIES

_Chlorobenzene_, and _nitro-_ and _dinitro-chlorobenzene_ and
_benzoylchloride_, have given rise to industrial poisoning.

To chlorobenzene similar action is attributed as to benzene (headache,
fainting, rapid breathing, cyanosis); changes in the blood (methæmoglobin
formation) have also been observed.

Nitro- and dinitro-chlorobenzene are active poisons; the effect
corresponds in general to that of nitro- and dinitrobenzene, but in
addition the fumes or dust have markedly irritant action on the skin
(dermatitis).

_Benzoylchloride_ (C₆H₅COCl), a colourless, pungent-smelling liquid,
produces a violently irritant effect upon the mucous membrane,
decomposing into hydrochloric acid and benzoic acid.

Treatment is analogous to that of benzene poisoning, and in cases of
benzoyl chloride poisoning to that by hydrochloric acid.

It may be mentioned that chlorine rash is attributed to the action of
chlorinated tar products (chlorobenzene compounds).


HYDROXYL SUBSTITUTION PRODUCTS

FATTY SERIES (ALCOHOLS)

The hydroxyl substitution products of the fatty series belong mainly
to the narcotic poisons; the greater the molecular weight of the
alcohol, the more marked is usually the narcotic effect. According to
this propylalcohol is eighteen times as poisonous as ethylalcohol;
butylalcohol and amylalcohol have from 36 to 120 times as great a
narcotic effect as methylalcohol.

_Methylalcohol_ (wood spirit, CH₃OH) plays relatively the greatest part
among alcohols as an industrial poison, because it is employed as a
means of denaturing spirit. Its poisonous nature is relatively great,
being very persistent. Industrial poisoning by methylalcohol is due to
inhalation of the vapour and is rarely of a severe nature. The fumes
have a strongly irritant effect upon the mucous membrane, giving rise to
throat irritation, cough, hoarseness, and in severe cases bronchitis and
inflammation of the conjunctiva of the eye. In addition inhalation of
methylalcohol vapour causes headache, giddiness, nausea (inclination to
vomit), and occasionally also twitchings and tremor.

The _higher alcohols_ (propyl-, butyl-, amyl-alcohol, C₃H₇.OH, C₄H₉.OH,
and C₅H₁₁.OH) occur in fusel oil. They cause but slight (if any)
industrial poisoning. Cases of more severe industrial poisoning through
amylalcohol fumes have been described (in factories for smokeless
powder), with symptoms of sickness, headache, giddiness, with fatal
issue in some cases, preceded by severe nervous symptoms (convulsions or
delirium).

Beyond speedy removal out of the dangerous atmosphere, probably no
special treatment is needed in these cases of industrial poisoning from
alcoholic vapour.


_GROUP: NITRO AND AMIDO COMPOUNDS OF THE ALIPHATIC AND AROMATIC SERIES
(BLOOD POISONS WHICH FORM METHÆMOGLOBIN)_

Characteristic of the nitro and amido compounds of the aliphatic and
aromatic series of the organic substances is their action upon the
blood. The normal oxyhæmoglobin (blood-colouring matter) is changed
into methæmoglobin, with which the oxygen is so firmly combined that
the internal exchange of gases necessary to life becomes impossible.
Methæmoglobin has a dark chocolate-brown colour and a clearly defined
characteristic spectrum.

Of the poisons belonging to this group several are important. In so
far as these substances are volatile—and this is generally the case
with those causing industrial poisoning—effects are due to inhalation
of fumes, but it is proved that the poisons of this group in liquid
form can be absorbed by the intact skin, and this channel of absorption
is characteristic of industrial poisoning. Severe poisoning results
especially from wetting the skin by spilling on the clothes, &c.

The grey-blue discoloration of the mucous membrane, especially of the
lips, is characteristic; sometimes also the skin is altered in colour.
This discoloration is often noticed by others before the patient feels
unwell. Soon the person affected has general nausea, vomiting, headache,
giddiness, severe nervous symptoms, feeling of anxiety, and difficulty
of breathing; in severe cases unconsciousness comes on, and death occurs
with increasing cyanosis (lividity).

Treatment is naturally that which has been emphasised in the introductory
words to Part II, which hold for all blood poisonings. In mild cases
oxygen treatment has given good results. In all factories where such
poisoning can occur provision should be made for immediate oxygen
treatment. Besides this, the workers must be adequately instructed as to
the danger and symptoms of poisoning, especially of the characteristic
premonitory skin discoloration, in order to be able to assist their
fellows.


NITROCOMPOUNDS

ALIPHATIC SERIES

_Nitro-glycerin_ (triple nitric acid ester of glycerin, C₃H₅.[NO₃]₃),
the well-known oily explosive liquid, has also an irritant local effect.
When absorbed into the body, in addition to methæmoglobin formation, it
causes dilatation of the bloodvessels, slowing of the respiration and
heart’s action, and attacks of suffocation. The general remarks upon this
group apply here, but symptoms referable to central paralysis occur as
the methæmoglobin formation is slow. Industrial poisoning arises through
inhalation of gases containing nitro-glycerin and also by absorption
through the skin. Statements as to its poisonous nature are very varied.
Under certain conditions moistening the skin with small quantities of
nitro-glycerin suffices to produce symptoms. Probably the susceptibility
of different persons varies greatly.

_Amylnitrite_ (nitric acid amyl ester, C₅H₁₁NO₂), a characteristically
smelling liquid, acts similarly. The fumes of amylnitrite, even when
inhaled in small quantities, cause marked dilatation of the bloodvessels,
through paralysis of the muscular walls of the bloodvessels, thus causing
marked flushing of the face; the pulse becomes quick, then weak and slow.


NITRO AND AMIDO COMPOUNDS

AROMATIC SERIES

The substances of this group are important.

_Nitrobenzene_ (C₆H₅NO₂, named oil of mirbane), a yellowish liquid of
characteristic smell, induces especially the formation of methæmoglobin
in the blood; the effect upon the central nervous system (first
excitation, then depression) is often absent. The description of the
disease in general in the introductory words of this whole group is
characteristic. Occasionally signs of asphyxia show themselves; sometimes
there are twitchings, disturbance of the power of sensation, and
convulsions; early discoloration of the mucous membrane and the skin,
which assume a blue to grey-black colour, is characteristic.

Chronic poisoning is also attributed to nitrobenzene, showing itself in
lassitude, headache, malaise, giddiness, and other disturbances of the
nervous system.

_Nitrotoluene_ (C₆H₄CH₃NO₂), of which the ortho-compound acts most
powerfully, and also _nitroxylene_ (C₆H₃[CH₃]₂NO₂) have similar but less
marked effect.

The _dinitrobenzenes_ (C₆H₄[NO₂]₂) are stable bodies. Meta-dinitrobenzene
inhaled as dust or otherwise, can produce marked poisoning symptoms
essentially the same as those described. Especially characteristic is the
early dark discoloration of the skin.

Symptoms resembling nitrobenzene poisoning in general are caused by
_nitrophenols_ (C₆H₄.OH.NO₂), of which paranitrophenol is the most
toxic; also by _dinitrophenols_ (C₆H₃[NO₂]₂OH), solid crystalline
substances which melt at different temperatures, and the _mono-_ and
_di-nitrochlorobenzenes_ (C₆H₄.Cl.NO₂ and C₆H₃.Cl[NO₂]₂). In cases of
industrial poisoning by dinitrophenol, observed by Leymann, the workers
were taken suddenly ill, with symptoms of collapse, pains in the chest,
vomiting, distress of breathing, rapid pulse, and convulsions, and died
within a few hours. At the autopsy a yellow substance was found with
picric acid reaction which appeared to be di- or tri-nitrophenol. In
other cases, some fatal, of industrial nitrochlorobenzene poisoning, also
observed by Leymann, the typical grey-blue discoloration of the skin
was obvious, and the chocolate-brown colour of the blood produced by
methæmoglobin.

_Trinitrophenol_ (picric acid, C₆H₂[NO₂]₃OH) is a yellow crystalline
compound with bitter taste; poisoning by this substance exhibits clearly
strong local irritant action (upon skin, mucous membrane, and intestinal
canal, and especially upon the kidneys), besides effect on the blood and
central nervous system. Prolonged action of picric acid upon the skin
causes inflammation. Absorption of picric acid dust causes inflammation
of the mucous membrane of the respiratory passages and symptoms of
gastric and intestinal catarrh as well as inflammation of the kidneys.

A jaundice-like discoloration of the skin and darkening of the urine are
also characteristic; sometimes picric acid poisoning produces a rash
resembling that of measles and scarlet fever.

_Nitronaphthalene_ (C₁₀H₇[NO₂]) and _nitronaphthol_ (C₁₀H₆.NO₂.OH) in
addition to methæmoglobin formation have an irritant action. It is stated
also that dulness of the cornea is produced.

_Azobenzenes_ also, which are to be considered as intermediate between
nitrobenzene and aniline, form methæmoglobin (azobenzene, C₆H₅N = NH₅C₆).

_Aniline_ (amidobenzene, C₆H₅.NH₂), a colourless, oily liquid of aromatic
smell, has only slight local irritant effect. In the frequent cases
of industrial poisoning by ‘aniline oil’ or aniline hydrochloride, in
which the aniline enters through the skin or is inhaled in the form
of fume, there appear the typical symptoms common to this group, of
the action upon the blood through methæmoglobin formation: headache,
weakness, cyanosis, difficulty in breathing, &c., to which are added
nervous symptoms such as convulsions and psychical disturbance, although
these play a subordinate part in industrial poisoning. In severe cases
the typical symptoms of air hunger are shown. Occasionally recovery
only takes place gradually, and signs of irritation of the kidneys
and inflammation of the urinary organs are seen. These symptoms occur
only rarely in acute industrial poisoning, but are, however, in so far
worthy of notice because of the frequent occurrence of tumours in the
bladder among aniline workers. It is possible that here the irritant
action of the urine which contains aniline plays a part. The tumours
in the bladder operated upon, in some cases with success, were many of
them non-malignant (papillomata), but some were carcinomata (cancerous
new growths) running a malignant course, and recurring after operation.
In the urine the aniline combines with sulphuric acid, and is partly
excreted as paramidophenol sulphuric acid.

The treatment of aniline poisoning is the same as that for all the
poisons of this group. In view of the occurrence of tumours of the
bladder in aniline workers, they should be instructed to seek medical
aid on the first indications of trouble, so that a careful cystoscopic
examination may be made.

_Toluidine_ (C₆H₄.CH₃.NH₂), which is mixed with aniline for industrial
use, produces the same symptoms with marked irritation of the renal
organs.

Of the _nitroanilines_ (C₆H₄.NH₂.NO₂) _paranitroaniline_ is the most
poisonous. Characteristic of the action of this compound is methæmoglobin
formation, central paralysis and paralysis of the heart’s action.

Of the _benzenediamines_, _paraphenylene diamine_ (C₆H₄[NH₂]₂) may be
regarded as an industrial poison. The irritant action of this substance
is prominent; it induces skin affections, inflammation of the mucous
membranes, more especially of the respiratory organs, and sometimes
inflammation of the kidneys. They have been noted in workers using ursol
as a dye; here, doubtless, the action of diimine (C₆H₄.NH.NH.) must be
taken into account, which arises as an intermediate product and exercises
a markedly irritant action. Further, the general effect of paraphenylene
diamine is an irritant one upon the central nervous system.


_APPENDIX_

TURPENTINE, PYRIDINE BASES, ALKALOIDS

_Turpentine oil._.—Turpentine oil is a peculiar-smelling, colourless
liquid of the composition C₁₀H₁₆; different reactions show that
turpentine oil contains the aromatic nucleus (cymene). It is used in
the manufacture of varnish, and thus can cause industrial poisoning
by inhalation of fumes. Even from 3 to 4 mg. of vapour of turpentine
oil per litre of air brings on severe symptoms. Turpentine oil acts as
a local irritant, and when absorbed into the system has an exciting
effect upon the central nervous system. Inhalation of large quantities
of turpentine vapour cause rapid breathing, palpitation, giddiness,
stupor, convulsions, and other nervous disturbances, pains in the chest,
bronchitis, and inflammation of the kidneys. The last-mentioned symptom
also arises from the chronic action of turpentine vapours.

_Pyridine._—Pyridine (C₅H₅N), a colourless liquid of peculiar odour, is
employed as well as methylalcohol in denaturing alcohol. The disturbance
of health observed in workers occupied with the denatured spirit are
probably mainly due to the inhalation of fumes of methylalcohol. Pyridine
is comparatively innocuous. Eczema, from which persons suffer who
come into contact with denatured spirit, is ascribed to the action of
pyridine. Larger doses produce a paralysing effect, but this need not be
considered in its industrial use.

_Nicotine, tobacco._—According to various published statements, effects
among tobacco factory workers are attributed to the nicotine contained
in tobacco dust and to the aroma which fills the air. Nicotine in large
doses has at first an exciting followed by a paralysing effect upon the
central nervous system; it causes moreover contraction of the unstriped
muscles and has a local irritant effect.

The symptoms of illness ascribed to nicotine are: conjunctivitis, catarrh
of the air passages, palpitation, headache, want of appetite, and,
particularly, tendency to abortion and excessive menstruation. Severe
industrial poisoning due to nicotine has only been observed in workers
who chewed tobacco leaves.

_Poisonous wood._—The symptoms of disease noticed in workers who
manipulate certain kinds of wood are attributed by some writers to the
presence of alkaloids. Such knowledge as we have of the illness due to
them—they are evidently of the nature of poisoning—is referred to at the
end of Part I.




PART III

_PREVENTIVE MEASURES AGAINST INDUSTRIAL POISONING_




I

_GENERAL MEASURES_


In discussing preventive measures against industrial poisoning the
deductive method from the general to the particular will be followed. The
numerous instances of poisoning mentioned in Part I afford a practical
basis on which to formulate general rules before passing on to describe
special measures. Technical details will be omitted, as they must be left
to the technical expert whose business it is to draw up the plans as a
whole and to modify them according to the requirements of individual
cases.

In the effort to control industrial poisoning and disease it is necessary
to insist absolutely on the concerted action of all concerned. In this
co-operation every one is called who through his knowledge and sphere of
activity is in a position to assist.

The medical man comes in with his special knowledge of the action of
poisons as toxicologist, as practising physician (especially as works
surgeon and doctor of the sick insurance society), and also in an
official capacity as appointed surgeon or medical officer of health; the
technical expert comes in as engineer, as manager, as foreman, and as
factory inspector. But above all the interest and active co-operation of
employers and employed are needed as well as the organisations of both.
That the workers should understand and co-operate is essential for the
success of preventive measures, and subsequently it will be shown in what
direction this co-operation is most necessary.

To make possible such co-operation interest must be aroused and
suitable information and teaching supplied to the parties concerned.
Medical men and practical workers require to receive instruction in
industrial hygiene, and teaching on this subject should be arranged
for in secondary and technical schools. Medical men and others who, as
officials and insurance doctors, are brought constantly into touch with
industrial workers should have opportunity—by means of special courses
and lectures—to keep pace with advancing knowledge in this direction.
Beside these there are, as educative organisations, special Institutes
of Industrial Hygiene and special hospitals for treatment of diseases
of occupation which bring together the patients and the teaching staff
and so facilitate pursuit of knowledge and research. A beginning of
this kind has already been made by the Industrial Hygiene Institute,
Frankfurt a.-Main, and the hospital for diseases of occupation at Milan,
showing that the ideas are attainable. International agencies which unite
all circles interested in the subject irrespective of profession or
nationality in common interchange of thought and discussion are of great
significance for uniform development of needful preventive measures;
international congresses, often in connection with exhibitions, have
given valuable stimulus and have been the starting-point of permanent
international societies, unions, and organisations. The significance
for our inquiry of these international efforts will be more closely
considered in the following pages.




II

_GENERAL CONSIDERATIONS ON SOCIAL AND LEGISLATIVE MEASURES_

INTERNATIONAL PREVENTIVE MEASURES, NOTIFICATION OF INDUSTRIAL POISONING,
LISTS AND SCHEDULES OF INDUSTRIAL POISONS


Experience and inquiry in the field of industrial poisoning led to a
series of demands which, supported as they were by a general movement
for the protection of workers, were soon followed by regulations and
legislative action. For a long time efforts have been directed to treat
industrial disease and poisoning in the same way as has been done in
the case of industrial accidents. The question, however, is attended
with much greater difficulty. On the other hand, uniform international
regulation of questions affecting prevention of disease is called for
both on humanitarian and economic grounds.

The idea of international legislation for the protection of workers
was first mooted about the year 1870. The possibility and need of such
intervention was much discussed and interest in it kept constantly alive,
especially in Switzerland, until the organisations of the workers took
up the idea. Several attempts failed. In France in 1883 a proposal of
the Socialist party aiming at international agreement on the subject
of protection of the workers was rejected. In 1885 (in opposition
to Hertling) Prince Bismarck expressed himself strongly against the
possibility of such international protection. But the stone, once set
rolling, could not be stayed. In the years 1886, 1887, and 1888 the
French and English trade unions, as well as the Swiss Federal Council,
took up the question afresh. These endeavours at last took tangible shape
in the first International Conference for the protection of workers held
in Berlin in March 1890. This date remains a landmark in the history of
the subject, but not until ten years later—1900—did the Congress held
in Paris for the international legal protection of workers lead to the
establishment of what had been repeatedly urged, namely, creation of an
International Bureau. This was inaugurated at Basle in 1901 and forms the
headquarters of the National Associations for Labour Legislation called
into being in various countries.

This International Association meets regularly in conference, as in
Cologne (1902), Berne (1905), Lucerne (1908), Lugano (1910), and Zurich
(1912). The questions raised in the International Labour Bureau,
which receives financial aid from a number of States, are fully and
scientifically discussed with the object of finding a basis on which to
bring into agreement the divergent laws of the different countries. A
further task of this strictly scientific institution is the collection
and publication of literature bearing on the protection of workers in
one and another country, distribution of information, and the editing of
reports and memoranda. The question of prevention of industrial poisoning
has always taken a foremost place in the programme of the International
Association and in the agenda of the International Labour Bureau. At its
first meeting a resolution was adopted advocating the prohibition of the
use of white phosphorus and white lead, and the Labour Bureau in Basle
was instructed to take the necessary steps. Special, if not prohibitive,
economical considerations foreshadowed difficulties—all the greater
because the matter at issue concerned prohibition of articles playing
a part in the markets of the world. Just on that account international
treatment of such questions is necessary, since a peaceful and orderly
solution can only be arrived at on such lines. International effort
endeavours here to press with equal weight on the countries competing
with one another commercially, so that in the protection of the workers
economic adjustment is sought in order that efforts based on humanitarian
grounds shall not at the same time cause economic disadvantages, the aim
being to produce general welfare and not merely protection of one class
at the expense of another.

Through these international agreements between various countries success
in the direction aimed at is hopeful, and indeed to a certain extent—as
in the phosphorus and lead questions—actually attained. Thus, for
example, Germany and Italy were in a position to enforce prohibition of
the use of white phosphorus early, while their neighbour Austria, on
account of commercial and political considerations and the conditions of
the home lucifer match industry, has only recently decided on prohibition.

As international agreement for the protection of workers is advisable
on economic grounds, so also is it reasonable and just from purely
humanitarian reasons that workers, without reference to civil condition
or nationality, should be equally protected. On this point it is proposed
to take a vote and to press only for those reforms which are thoroughly
sound and recognised as necessary.

The first step in such a comprehensive attack is precise knowledge of
the extent and source of origin of the particular forms of industrial
poisoning and disease and the collection of reliable statistics. This
suggested the obligation to notify such cases to the proper authorities
in the same way as is now done in the case of infectious disease. A
motion to this effect had already been passed at the Conference of the
International Association for Labour Legislation held in Basle, and a
request was made to the Labour Bureau to prepare a list of the diseases
and poisonings in question. To them we shall refer later, but a schedule
is necessary as a basis to work upon. Yet even when this is done there
are obviously great difficulties to be overcome in carrying out the
requirement of notification when the aim is kept in mind of collecting
complete statistical data for controlling the conditions giving rise
to industrial disease. The proposal of the International Association
seeks to make notification obligatory on the part both of the medical
practitioner in attendance and the occupier, and in connection with
this to secure the co-operation of the Sick Insurance Society.[D] The
proposal to require the appointed surgeons and surgeons of the Insurance
Society to notify all cases is hardly feasible in view of their dependent
position. Nor can the obligation on the occupiers lead to the desired
result because of their lack of medical knowledge and the fact that
by notifying they might be forced to act to their own disadvantage. A
successful effort in this direction is recorded in Saxony, where lead
poisoning was first made a notifiable disease, and later the general duty
of notification of industrial poisoning was prescribed by Order dated
March 4, 1901.

  +-----------------------+-----------------------------------------------+
  |                       |              Reported Cases.[E]               |
  | Disease and Industry. +-------+-------+-------+-------+-------+-------+
  |                       | 1912. | 1911. | 1910. | 1909. | 1908. | 1907. |
  |         (1)           |  (2)  |  (3)  |  (4)  |  (5)  |  (6)  |  (7)  |
  +-----------------------+-------+-------+-------+-------+-------+-------+
  |Lead Poisoning         |587 (44|669 (37|505 (38|553 (30|646 (32|578 (26|
  |  1. Smelting of metals| 56  (7| 48  (3| 34  (5| 66  (5| 70  (2| 28  (2|
  |  2. Brass works       |  5    |  9  (1|  7    |  5    |  6    |  9  (1|
  |  3. Sheet lead and    |       |       |       |       |       |       |
  |       lead piping     |  6    | 12    |  4    |  9  (2| 14    |  6    |
  |  4. Plumbing and      |       |       |       |       |       |       |
  |        soldering      | 35  (5| 37  (2| 25  (1| 28    | 27    | 20  (2|
  |  5. Printing          | 37    | 32  (2| 33  (4| 21  (1| 30  (2| 26  (3|
  |  6. File cutting      | 13    | 18  (2|  9  (1|  8    |  9  (2| 10    |
  |  7. Tinning           | 15 (11| 13    | 17    | 22    | 10    | 25    |
  |  8. White lead        | 23    | 41  (2| 34  (1| 32  (2| 79  (3| 71    |
  |  9. Red lead          |  3    | 13  (1| 10    | 10    | 12    |  7    |
  | 10. China and         |       |       |       |       |       |       |
  |        earthenware    | 80 (14| 92  (6| 77 (11| 58  (5|117 (12|103  (9|
  |10a. Litho-transfers   |  1  (1|  1    |  1    |  1    |  2    | 10    |
  | 11. Glass cutting and |       |       |       |       |       |       |
  |       polishing       |  1  (1|  5    |  —    |  4  (2|  3  (1|  4    |
  | 12. Vitreous          |       |       |       |       |       |       |
  |        Enamelling     |  5    | 19  (1| 17    |  7    |  7    |  6    |
  | 13. Electric          |       |       |       |       |       |       |
  |        accumulators   | 38  (1| 24  (1| 31    | 27  (2| 25  (1| 21    |
  | 14. Paints and colours| 19    | 21    | 17  (1| 39  (2| 25    | 35  (1|
  | 15. Coach building    | 84  (7|104  (5| 70  (6| 95  (6| 70  (3| 70  (3|
  | 16. Ship building     | 34  (2| 36  (6| 21  (2| 27  (1| 15    | 22  (1|
  | 17. Paint used in     |       |       |       |       |       |       |
  |       other industries| 48  (3| 56  (1| 51  (3| 42    | 47  (1| 49  (2|
  | 18. Other industries  | 84  (2| 88  (4| 47  (3| 52  (2| 78  (5| 56  (2|
  |                       |       |       |       |       |       |       |
  |Phosphorus Poisoning   |  —    |  —    |  —    |  3    |  1    |  1  (1|
  |                       |       |       |       |       |       |       |
  |Arsenic Poisoning      |  5    | 10  (1|  7    |  4    | 23  (1|  9  (2|
  |                       |       |       |       |       |       |       |
  |Mercurial Poisoning    | 17    | 12    | 10  (1|  9    | 10    |  7    |
  |                       |       |       |       |       |       |       |
  |Anthrax                | 47    | 64 (11| 51  (9| 56 (12| 47  (7| 58 (11|
  | Wool                  | 31  (6| 35 (10| 28  (3| 28  (3| 18  (3| 23  (3|
  | Horsehair             |  7    |  8  (1|  6  (1|  8  (2| 10    | 17  (4|
  | Handling of hides and |       |       |       |       |       |       |
  |   skins               |  8    | 20    | 14  (3| 18  (6| 13  (1| 12  (2|
  | Other industries      |  1    |  1    |  3  (2|  2  (1|  6  (3|  6  (2|
  +-----------------------+-------+-------+-------+-------+-------+-------+

  +--------------+-------+-------+-------+-------+-------+-------+--------+
  |              | 1906. | 1905. | 1904. | 1903. | 1902. | 1901. |  1900. |
  |              |  (8)  |  (9)  | (10)  | (11)  | (12)  | (13)  |  (14)  |
  +--------------+-------+-------+-------+-------+-------+-------+--------+
  |Lead          |632 (33|592 (23|597 (26|614 (19|629 (14|863 (34|1058 (38|
  |   1.         | 38  (1| 24  (1| 33  (1| 37  (2| 28    | 54  (3|  34  (1|
  |   2.         | 11    |  5  (1| 10  (1| 15    |  5    |  6  (1|   3    |
  |   3.         |  7    |  9    |  7    | 11    | 12    | 17    |  17  (1|
  |   4.         | 16  (4| 24  (2| 21  (3| 26    | 23  (1| 23    |   9    |
  |   5.         | 16  (2| 19  (4| 15    | 13  (2| 19    | 23  (1|  18  (2|
  |   6.         | 15    | 12    | 20  (4| 24  (2| 27  (1| 46  (7|  40  (3|
  |   7.         | 18  (1| 14  (1| 10    | 14    | 11    | 10    |   5    |
  |   8.         |108  (7| 90    |116  (2|109  (2|143  (1|189  (7| 358  (6|
  |   9.         |  6    | 10    | 11    |  6    | 13    | 14    |  19    |
  |  10.         |107  (4| 84  (3|106  (4| 97  (3| 87  (4|106  (5| 200  (3|
  | 10a.         |  5    |  5    |  3    |  3    |  2    |  7    |  10    |
  |  11.         |  4  (1|  3    |  —    |  4    |  8  (2| 11  (3|   7    |
  |  12.         |  4    |  2    |  3    |  4    |  3  (1|  9    |  11    |
  |  13.         | 26    | 27  (1| 33    | 28    | 16  (1| 49  (1|  33    |
  |  14.         | 37    | 57  (1| 32  (1| 39  (1| 46    | 56    |  56  (1|
  |  15.         | 85  (7| 56  (3| 49  (4| 74  (5| 63  (1| 65  (4|  70  (5|
  |  16.         | 26  (1| 32  (2| 48    | 24  (1| 15  (1| 28  (1|  32  (2|
  |  17.         | 37  (3| 49  (2| 27  (3| 46  (1| 44  (1| 61    |  50  (5|
  |  18.         | 66  (2| 70  (1| 53  (3| 40    | 64    | 89  (1|  86  (4|
  |              |       |       |       |       |       |       |        |
  |Phosphorus    |  —    |  3  (1|  1  (1|  —    |  1  (2|  4    |   3    |
  |              |       |       |       |       |       |       |        |
  |Arsenic       |  5    |  1    |  5    |  5    |  5    | 12  (1|  22  (3|
  |              |       |       |       |       |       |       |        |
  |Mercurial     |  4    |  8    |  3    |  8    |  8    | 18    |   9    |
  |              |       |       |       |       |       |       |        |
  |Anthrax       | 67 (22| 59 (18| 50 (10| 47 (12| 38  (9| 39 (10|  37  (7|
  |  Wool        | 24  (8| 34 (12| 12  (1| 20  (5| 12  (2|  6  (4|   9  (2|
  |  Horsehair   | 10  (4|  7  (1| 12  (4|  7  (1| 10  (2|  9  (1|  12  (3|
  |  Hides       | 19  (7| 17  (4| 18  (3| 12  (1| 11  (5| 20  (5|   9  (1|
  |  Other       | 14  (3|  1  (1|  8  (2|  8  (5|  5    |  4    |   7  (1|
  +--------------+-------+-------+-------+-------+-------+-------+--------+

My own experience does not lead me to expect much in elucidation of
industrial diseases from the Sick Insurance Societies. In Austria they
make a statistical return as to the causation of illness to the central
authorities. I have myself—in my capacity as an official of the State
Central Board—examined these in order to try and gain knowledge of
the extent of industrial disease in Bohemia. In spite of the returns
drawn up by the district surgeon who visits the factories in question,
it was impossible for me to obtain a complete picture of the extent
of industrial sickness. The reports only give valuable data on which
to base action in particular cases, and from this standpoint I do not
under-estimate their value. But so far as the expressed wish of the
International Association is concerned they appear to fulfil it, inasmuch
as for specially dangerous trades special reports are issued, the
Austrian law for sick insurance requiring such industries to institute
separate sick insurance funds with separate statistics. Hence, under
present conditions, I do not see how the duty of notification will be
effective. There remains the endeavour to secure insurance and the
right to claim compensation for industrial disease in the same way as
is provided for accidents. This point was fully discussed at the eighth
International Congress for Workmen’s Insurance held in Rome in 1908.
There is no valid ground for granting compensation only for _sudden_
disturbance of health arising in the course of employment by accident or
acute poisoning, and withholding it in the case of _gradual_ disturbance
of health caused equally by the trade, as the effects of such chronic
indisposition weigh often no less heavily on the sufferer. Inclusion
of industrial disease in the same category as accident insurance, as
indeed has been done in France, Switzerland and Great Britain, has,
apart from the fact that it is dictated by fairness and humanity, the
advantage of removing existing hardship and of solving doubtful cases.
Correct statistics, further, would thus be obtainable for the first
time, and the employer by insurance would be freed from the legal
proceedings now frequently brought against him for injury due to chronic
industrial poisoning. And it seems the more right and just course to
institute a general scheme of insurance against industrial disease than
to have recourse to an Employer’s Liability Act in this or that case,
particularly as the question often arises in regard to a disease which
develops gradually—In whose employment was the disease contracted?

Clearly in such a scheme of insurance against both accident and
industrial disease only specific industrial diseases would be included,
i.e. diseases in which the connection with the industry can be clearly
established as due to causes inherent in the industry, and traceable to
definite materials used. Such diseases as tuberculosis and the effects
of dust inhalation (bronchitis, &c.), which as industrial diseases occur
only too often, cannot be called specific, because they arise outside
the industry and make decision impossible as to whether or not in a
particular case the disease owed its origin to the occupation. In order
to determine what should be regarded as specific industrial poisons it
was deemed necessary to draw up a schedule. For one such list Sommerfeld
(in collaboration with Oliver and Putzeys) is responsible, Carozzi of
Milan for a second, and Fischer[F] for a third, published in 1910. Those
by Sommerfeld and Fischer are constructed in similar fashion—enumeration
of (1) the poisonous substance, (2) the industries in which it is made
or used, (3) the channel of absorption, and (4) the symptoms produced.
Sommerfeld enumerates the poisons in alphabetical order, noting against
each the requisite preventive measures, while Fischer adopts a chemical
classification, confining himself to general introductory remarks as to
prevention.

Sommerfeld proposes to limit notification to poisoning sharply
defined as to the symptoms set up, such as lead, phosphorus, mercury,
arsenic, chromium, carbonic oxide, aniline, benzene, nitrobenzene,
carbon bisulphide, and nitrous fumes. This simplifies the obligation
to notify, but does not dissipate the fears expressed above as to the
difficulty, because in the present development of the chemical industries
new substances involving new danger to the persons handling them are
constantly being discovered, and thus there can be no finality as to
which industrial poisonings should entitle to compensation. And if
recourse were had from time to time to additions of new substances to
the schedule, reliance would have to be placed on experience with regard
to each substance added, and thus the actual individual who had suffered
would not benefit. Fischer, indeed, acknowledges that any schedule must
be incomplete, and emphasises the fact that continual additions would
be necessary; otherwise it would be better to refrain altogether from
publication of a list. Such lists may be valuable guides, but no sure
foundation for insurance legislation. The only possible way to do this
is to give as far as possible a correct definition of the industrial
diseases entitling to compensation and, in isolated cases, to leave the
decision to the expert opinion of competent judges.

Extension of workmen’s insurance to cover chronic industrial poisoning
is, however, most desirable in the interest of employers and employed,
and also of science. The German accident insurance legislation is
especially suited to do this, since the trade organisations direct their
attention not only to the prevention of accidents but of industrial
diseases also.




III

_SPECIAL PREVENTIVE MEASURES FOR WORKERS_

SELECTION, CHOICE OF TRADE, ALTERNATION OF EMPLOYMENT, MEDICAL CONTROL,
SAFETY APPLIANCES, INSTRUCTION AND CO-OPERATION OF WORKERS, CLOTHING,
ATTENTION TO CLEANLINESS, FOOD, GENERAL WELFARE


As a practical measure in protection against trade risk selection of
those capable of resisting danger has to be considered. It is obviously
desirable to select for employment in a dangerous trade persons
possessing powers of resistance, because predisposition and resistance
to the action of poisons differ markedly in individuals. To some extent
such a selection comes of itself, as those who are very susceptible
are obliged by repeated attacks to give up the work. The social and
physical misery, undeserved loss of employment, illness, and perhaps
early death following on this kind of selection might be checked by
timely medical examination so as to weed out the unfit. But medical
examination prior to admission into a dangerous trade (actually practised
in many industries involving risk of poisoning) inflicts hardship on
those seeking employment, and recruits the ranks of the unwillingly
unemployed. It would be much better were it possible to meet the need
of selection by pertinent direction and guidance in choice of calling.
There should be insistence in technical schools especially on the
dangers inherent in certain industries, school medical examination as to
physical qualifications for certain industries, and careful note made of
individual suitability in labour bureaus, apprentice agencies, and the
like.

Young female workers, naturally less able to resist, should be excluded
from work involving risk of poisoning—a principle which has been acted on
in the legislation of civilised countries.

Further, workers engaged in industries involving risk should not be
exposed to the pernicious influence for too long a time. Hence the
hours of employment should be shortened in occupations proved to be
injurious to health. An important aid in this respect is alternation of
employment. Change of occupation is particularly recommended where the
nature of the poisoning of which there is risk is cumulative in action,
because in the intervals from the work the system will rid itself of the
accumulated store. In this way a number of skilled resistant workers,
familiar with the risk and knowing how to meet it, will be maintained.
Casual labour works in a vicious circle—increase of fresh workers
increases the danger and the number of cases of poisoning, and, _vice
versa_, these augment again the need of change in the personnel, so that
the number of cases of poisoning rises very high. Thus the industry
itself may be endangered, since its prosperity depends mainly upon the
existence of a skilled staff of workers. In dangerous trades, therefore,
Hermann Weber’s words, ‘Change of work instead of change of workers,’
have much force.

Periodical medical examination in these industries cannot well be omitted
in order to weed out the physically unfit, and to suspend from work those
who show early symptoms. Note should be kept of the state of health of
the workers, the results of the periodical medical examination, the
duration of symptoms, and the treatment of any illness that occurs.
Medical supervision presupposes special training and experience in the
medical man entrusted with the task.

Further, in some industries in which poisonous materials are used,
especially such as set up acute sudden poisoning, there should be a
trained staff competent to recognise the first symptoms of poisoning and
to render first aid, and having at its disposal adequate means of rescue.

Apart from the rescue appliances generally needed in dangerous trades,
stress must be laid on the value of oxygen apparatus as a means of
saving life. In addition to what is needed for the sufferer there must
be defensive apparatus at hand for the rescuers (breathing helmets,
&c.), to facilitate and make safe their rescue work when in a poisonous
atmosphere. Without such defensive equipment rescuers should never
venture into gas conduits, or into any place where presumably a poisonous
atmosphere is to be met with. It hardly requires to be said that in
dangerous industries medical aid should be within easy reach; in large
works actual medical attendance may be necessary.

In acute as well as in chronic cases of poisoning early medical
intervention is advisable. Hence medical aid should be sought on the
earliest appearance of symptoms, and the worker, therefore, should
know the nature and action of the poison with which he comes into
contact. This brings us to the subject of the education of the worker
and particularly observance of all those rules and regulations in which
his co-operation is necessary. This co-operation of the workers is
indispensable; it is the most important condition of effective defence.
The best regulations and preventive measures are worthless if the worker
does not observe them. He must be taught their aim, the way of using the
means of defence; he must be admonished to use them, and, if necessary,
compelled to do so. The co-operation of workmen’s organisations in this
matter can avail much, since a workman most readily follows the advice of
a fellow-worker.

Teaching of the kind suggested can be done in different ways. Apart from
lectures and practical courses, concise instructions, either in the
form of notices or as illustrated placards, should be posted up in the
workrooms or handed in the form of leaflets particularly to the newly
employed. Distribution of such leaflets might well be placed as a duty on
the employer.

Of preventive measures applying to the individual those are of prime
importance which serve to protect the worker, as far as is practicable,
from coming into contact with the poison. Protection of this kind is
attained by wearing suitable clothing, use of respirators, and careful
cleanliness—especially before partaking of food. It cannot be too
strongly urged that these precautions are a very potent defence against
the danger of industrial poisoning, especially of the chronic forms,
and in teaching workers their importance must be insisted on. It is not
sufficient merely to put on overalls over the ordinary clothes. The
ordinary clothes must be taken off before the commencement of work, and
working suits put on, to be taken off again before the principal midday
meal and before leaving work. They should be made of smooth, durable,
washable material, and be properly washed and dried not less often than
once a week. They must be plainly cut without folds or pockets.

Direct handling of the poisonous substances is to be avoided, but where
this is necessary impervious gloves may have to be worn, especially in
the case of poisons which can be absorbed through, or act injuriously on,
the skin. If there is risk of splashing or spilling of poisonous liquids
on to the clothes, impermeable or partly impermeable overalls (aprons,
&c.) should be worn. The obligation of providing the overalls or working
suits falls naturally on the employer in industries where poisonous
substances are used, and there is equally obligation on the employee to
use the articles provided.

Suitable cloakroom accommodation is essential, by which is meant room not
only to change clothes with cupboards or hooks on one side for clothing
taken off on commencement of work and on the other the working suits,
but also ample washing accommodation. These cupboards should be double,
that is, be divided by a partition into two parts, one serving for the
ordinary and the other for the working clothes.

[Illustration: FIG. 35.—Aluminium Respirator]

Protection of the respiratory organs can to some extent be obtained by
so-called respirators worn over the mouth and nose. Often they consist
simply of a moist sponge or folds of cloth, or again may be complicated
air-proof affairs enclosing mouth and nose, or the whole face like a
mask, or even the head like a helmet; they fit close, and the aperture
for respired air is provided with filtering material (cotton wool, &c.)
placed between two layers of wire gauze. The outer layer of the gauze
moves on a hinge, so that the filtering material can be renewed after
each time that it has been used. The construction of respirators is
extraordinarily varied. One form is illustrated. They must be light, and
in order not to obstruct breathing seriously they are often provided
with valves—closing during inspiration and opening during exhalation.
Generally the respirators in common use do not quite satisfactorily
fulfil the conditions required. After a time the pressure becomes
irksome, the face becomes hot, breathing more difficult, and discomfort
from wearing them unbearable.

Respirators are only to be regarded in the light of secondary aids and
for occasional use.

During temporary exposure to an atmosphere charged with poisonous dust
the wearing of an efficient apparatus—preferably one protecting the
head—is very desirable.

[Illustration: FIG. 36.—Smoke Helmet, Flexible Tubing, and Foot Bellows
(_Siebe, Gorman & Co._)]

Respirators afford no protection, or a very imperfect one, against
dangerous gases or fumes. If soaked with an absorbing or neutralising
fluid they can scarcely be worn for any length of time.

In an atmosphere charged with poisonous gas recourse should be had either
to a smoke helmet with flexible tubing and bellows or to an oxygen
breathing apparatus so constructed that the workman carries the necessary
supply of oxygen with him in a knapsack on his back. In the latter case
oxygen from a compressed cylinder of the gas is conveyed to the breathing
mask, so that respiration is independent of the surrounding atmosphere.

[Illustration: FIG. 37.—Diagram of Draeger 1910-11, Pattern H (_R.
Jacobson_)

P Alkali cartridges; K Cooler; C Aspirating pipe; L₁ Purified air; L₂
Expired air.]

The mode of working is represented diagrammatically in figs. 37 and 40.
After putting on the helmet, the bag is first filled with fresh air, the
air valve is then closed, and the valve of the oxygen cylinder unscrewed
so as to permit of the flow of the oxygen which, mixes with the air in
the bag, and begins to circulate; the expired air passes through the
caustic potash pellets P, which free it of carbonic acid gas, so that,
with a fresh supply of oxygen from the cylinder through the pipe C, it
is regenerated and made fit for breathing again. The pressure in the
cylinder is measured by a manometer, which indicates also when the supply
of oxygen gives out.

[Illustration: FIG. 38.—Showing the Potash Cartridge No. 2 with Change
Mechanism X; No. 2 Oxygen Cylinder with Spanner V; and on the Left a
Hexagonal Socket U, for unscrewing the Locking Nuts of Reserve Cylinders
(_R. Jacobson_)]

[Illustration: FIG. 39.—‘Proto’ patent self-contained breathing apparatus
(_Siebe, Gorman & Co._)]

    Another apparatus—the ‘Proto’ patent self-contained breathing
    apparatus (Fleuss-Davis patents)—is also illustrated in fig.
    39. Illustration 40 gives a diagrammatic view of the principle
    upon which it is designed. The instructions for using the
    ‘Proto’ apparatus are as follows:

    _The oxygen cylinders_ (B, B), having been charged with oxygen
    through the nipple at (H) to a pressure of 120 atmospheres
    (about 1800 lbs. per square inch), are to be re-attached to
    the belt as shown, and the reducing valve, with its tubes,
    &c., is to be connected to the nipple at (H). This supply is
    sufficient for fully two hours.

    _Charging the breathing bag._—Put 4 lbs. of stick caustic
    _soda_ into the bag (D), i.e. 2 lbs. into each compartment,
    and immediately fasten the mouth of the bag by means of the
    clamps and wing nuts (O). If the apparatus is not to be used
    at once, but is to be hung up for use at some future time, the
    indiarubber plug which is supplied with the apparatus should be
    tightly fitted into the mouthpiece in order to prevent access
    of air to the caustic soda, and to preserve it until required
    for use.

    See that the inlet and outlet valves (T and S) and the
    connection (N) are screwed up tightly.

    The small relief valve (K) is only to be opened (by pressing
    it with the finger) when the bag becomes unduly inflated
    through excess of oxygen. This may occur from time to time,
    as the reducing valve is set to deliver more than the wearer
    actually requires.

    _Equipment._—The whole apparatus is supported upon a broad belt
    which is strapped round the body. The bag is also hung by a
    pair of shoulder braces.

    The wearer having put the equipment over his shoulders, fastens
    the belt and takes the plug out of the mouthpiece. The moment
    the mouthpiece is put into the mouth or the mask is adjusted,
    the main valve (H) is to be opened not more than one turn and
    the necessary supply of oxygen will then flow into the bag. It
    is advisable to open the by-pass (I) to inflate partially the
    breathing bag (D) for a start, but this valve should again be
    screwed up quite tight and not touched again, except in the
    case of emergency as previously described should the bag become
    deflated. Breathing will then go on comfortably.

    Should the by-pass (I) on the reducing valve (C) get out of
    order then the wearer should turn on the by-pass (I) from time
    to time to give himself the necessary quantity of oxygen, but,
    as stated above, this is only to be done in case of deflation
    of the bag. The best guide as to the quantity of oxygen to
    admit _in the above circumstances_ is the degree of inflation
    of the breathing bag. It will be found to be quite satisfactory
    if the bag be kept moderately distended.

    _After using the apparatus._—The caustic soda should _at once_
    be thrown away, but if it is neglected and the soda becomes
    caked, it must be dissolved out with warm water before putting
    in a fresh supply. Caustic soda will not damage vulcanised
    indiarubber, but it will damage canvas and leather, and will
    burn the skin if allowed to remain upon it.

    If the apparatus is to be used again at once, it can be
    recharged with caustic soda at once, but if it is only to be
    charged ready for use at some future time the indiarubber bag
    should be thoroughly washed out with warm water and dried
    inside with a cloth or towel.

    When emptying or recharging the rubber bag with caustic soda,
    it must always be removed from the canvas bag. After use each
    day, it is advisable to wash the rubber mouthpiece (or mask,
    as the case may be) with yellow soap and water. This acts as a
    preservative to the indiarubber.

    Every man who is to use the apparatus should have his own
    mouthpiece and noseclip, or mask, as the case may be, under
    his own special care, both for sanitary reasons and so that he
    may shape and adjust the mask to fit himself comfortably and
    air-tightly, to such an extent that if the outlets are stopped
    up by the hands while the mask is held in position by its bands
    no breath can pass in or out.

[Illustration: FIG. 40.—‘Proto’ Patent Self-breathing Apparatus (_Siebe,
Gorman & Co._)]

[Illustration: FIG. 41.—Arrangement of Cloak-room, Washing and Bath
Accommodation, and Meal-room in a White Lead Factory]

Where poisonous substances giving off dust or fumes are used, regular
washing and rinsing the mouth (especially before meals and on leaving)
is of great importance. Naturally the washing conveniences (basins,
soap, brushes, towels) must be sufficient and suitable, and the workers
instructed as to the importance of cleanliness by the foreman. They
should be urged to bath in rotation, and time for it should be allowed
during working hours.

The taking of meals and use of tobacco in the workrooms must be
prohibited. Meal rooms should be so arranged as to be contiguous to the
cloakroom and washing accommodation, the worker gaining access to the
meal room through the cloakroom and bathroom. The arrangement described
is illustrated in fig. 41. The meal room serves also the purpose of a
sitting-room during intervals of work, and it goes without saying that
cloakroom and lavatory accommodation are as necessary in small as in
large premises.

Simple lavatory basins of smooth impervious surface fitted with a waste
pipe and plug, or tipping basins, are recommended in preference to
troughs which can be used by several persons at once. Troughs, however,
without a plug, and with jets of warm water, are free from objection.

The douche bath has many advantages for workmen over the slipper bath.
The initial cost is comparatively small, so that it can be placed at the
disposal of the workers at very small outlay. Maintenance and cleanliness
of douche baths are more easily secured than of other kinds, where
changing the water and keeping the bath in good order involve time and
expense. A dressing-room should form part of the douche or slipper bath
equipment. Walls and floors must be impervious and, preferably, lined
with smooth tiles or cement. It is better that the shower bath should be
under the control of the worker by a chain rather than be set in motion
by means of mechanism when trodden upon. The arrangement of baths is
illustrated in fig. 43. In many large works large bath buildings have
been erected. Fig. 44 is a plan of the splendid bath arrangements at the
colour works of Messrs. Lucius, Meister & Brüning of Höchst a.-M.

[Illustration: FIG. 42.—Good Washing and Bath Accommodation in a Lead
Smelting Works]

[Illustration: FIG. 43.—Washing Trough, Douche Baths, and Clothes
Cupboards, Type common on the Continent]

[Illustration: FIG. 44A.—Baths in the Höchst Aniline Works (_after
Grandhomme_)]

[Illustration: FIG. 44B.—Ground Floor]

[Illustration: FIG. 44C.—First Floor. _a_, _c_, Baths (slipper and
douche) for workmen; _b_, Washing accommodation for workmen; _d_, _e_,
Baths for officials; _g_, Attendant’s quarters; _f_, Hot air (Turkish)
baths; _i_, Warm water reservoir.]

Naturally maintenance of the general health by good nourishing diet is
one of the best means of defence against onset of chronic industrial
poisoning. Over and over again it has been noticed that ill-fed workers
speedily succumb to doses of poison which well-nourished workers can
resist. It is not our province here to discuss fully the diet of a
working-class population. We merely state that it is a matter of vital
importance to those employed in dangerous trades. The question of a
suitable drink for workers to take the place of alcohol calls for special
attention, as, when complicated with alcoholism, both acute and chronic
poisonings entail more serious results than they otherwise would do.
Over-indulgence in alcohol, owing to its effect on the kidneys, liver,
digestion, nervous system, and power of assimilation generally, requires
to be checked in every way possible. Apart from good drinking water,
milk, coffee, tea, fruit juices and the like, are excellent. Milk is
especially recommended, and should be supplied gratis to workers in
dangerous trades, notably where there is risk of lead poisoning.

Lastly, other features such as games and exercise in the open air,
which help to strengthen bodily health, must not be forgotten. In this
connection much good work has already been done by employers’ and
workers’ organisations.




IV

_GENERAL REMARKS ON PREVENTIVE MEASURES_

GENERAL PRINCIPLES, SUBSTITUTES FOR DANGEROUS MATERIALS, CLEANLINESS OF
WORKROOMS, CUBIC SPACE, VENTILATION, REMOVAL OF DUST AND FUMES


Preventive measures against industrial poisoning aim at an unattainable
goal of so arranging industrial processes that employment of poisonous
substances would be wholly avoided. Such an ideal must be aimed at
wherever practicable. Prohibition of direct handling of poisonous
substances is also sometimes demanded, which presupposes (although it is
not always the case) that this is unnecessary or can be made unnecessary
by suitable mechanical appliances. We have to be contented, therefore,
for the most part, with removal of injurious dust and fumes as quickly
as possible at the point where they are produced, and regulations
for the protection of workers from industrial poisoning deal mainly
with the question of the prevention of air contamination and removal
of contaminated air. Substitution of non-injurious for injurious
processes is only possible in so far as use of the harmless process
gives technically as good results as the other. If such a substitute
can be found let it be striven for. Mention has already been made of
international prohibition of certain substances, and attention has been
drawn to economical considerations affecting this point.

Prohibition obviously may paralyse branches of industry and hit heavily
both employers and employed. The skilled trained workers are just the
ones to suffer, since they are no longer in a position to take up another
equally remunerative trade.

Judgment has to be exercised before enforcing new regulations in order
that good and not harm may follow. If a satisfactory substitute be
discovered for methods of work injurious to health, then ways and
means will be found to make the alteration in the process economically
possible. It may, however, demand sacrifice on the part of employers and
employed, but the progress is worth the sacrifice.

The following are instances of substitution of safe processes for those
involving risk: generation of dust can sometimes be avoided by a ‘wet’
method (watering of white lead chambers, grinding pulp lead with oil,
damping of smelting mixtures, &c.); the nitrate of silver and ammonia
process has replaced the tin and mercury amalgam used in silvering of
mirrors; electroplating instead of water gilding (coating objects with
mercury amalgam and subsequently volatilising the mercury); enamelling
with leadless instead of lead enamels; use of air instead of mercury
pumps in producing the vacuum in incandescent electric lamps.

Dealing further with the sanitation of the factory and workshop after
personal cleanliness, the next most important measure is cleanliness of
the workroom and purity of the air. Workrooms should be light and lofty;
and have floors constructed of smooth impervious material easily kept
clean. The walls should be lime-washed or painted with a white oil paint.
Angles and corners which can harbour dirt should be rounded. Cleansing
requires to be done as carefully and as often as possible, preferably by
washing down or by a vacuum cleaner. Saturation of the floor with dust
oil is recommended by some authorities in trades where poisonous dust is
developed and is permitted as an alternative to the methods described. I
refrain from expressing an opinion on this method of laying dust, since
by adoption of the practice insistence on the need for removal of the
poisonous material from the workrooms loses its force—a thing, in my
opinion, to be deprecated.

The necessity of keeping the atmosphere of workrooms pure and fresh
makes it essential that there should be sufficient cubic space per
person and that proper circulation of the air should be maintained. The
minimum amount of cubic space legally fixed in many countries—10-15
cubic metres—is a minimum and should be greatly exceeded where possible.
Natural ventilation which is dependent upon windows, porosity of building
materials, cracks in the floors, &c., fails when, as is desirable for
purposes of cleanliness, walls and floors are made of smooth impermeable
material, and natural ventilation will rarely supply the requisite cubic
feet of fresh air quickly enough. Ordinarily, under conditions of natural
ventilation, the air in a workroom is renewed in from one to two hours.
Artificial ventilation therefore becomes imperative. Natural ventilation
by opening windows and doors can only be practised in intervals of work
and as a rule only in small workrooms. During work time the draught and
reduction of temperature so caused produce discomfort.

_Artificial ventilation_ is effected by special openings and ducts
placed at some suitable spot in the room to be ventilated and arranged
so that either fresh air is introduced or air extracted from the room.
The first method is called propulsion, the latter exhaust ventilation.
Various agencies will produce a draught in the ventilating ducts, namely,
difference of temperature between the outside and inside air, which can
be artificially strengthened (_a_) by utilising the action of the wind,
(_b_) by heating the air in the exhaust duct, (_c_) by heating apparatus,
and (_d_) by mechanical power (use of fans).

Where advantage is taken of the action of the wind the exit to the
ventilating duct must be fitted with a cowl.

The draught in pipes is materially increased if they are led into furnace
flues or chimneys; in certain cases there is advantage in constructing
perpendicular ventilating shafts in the building extending above the roof
and fitted with cowls. Combination of heating and ventilation is very
effective.

[Illustration: FIG. 45.—Steam Injector (_after Körting_), showing steam
injector and air entry]

In workrooms, however, where there is danger of poisoning by far the
most effective method of ventilation is by means of fans driven by
mechanical power. All the means for securing artificial ventilation
hitherto mentioned depend on a number of factors (wind, difference of
temperature, &c.), the influence of which is not always in the direction
desired. Exact regulation, however, is possible by fans, and the quantity
of air introduced or extracted can be accurately calculated beforehand
in planning the ventilation. In drawing up such a plan, detailing the
arrangement, proportions of the main and branch ducts, expenditure of
power, &c., a ventilating engineer should be consulted, as it is his
business to deal with complicated problems of ventilation depending
entirely for success on the design of the ventilation.

Injectors are usually only employed for special technical or economical
reasons. A jet of steam or compressed air which acts on the injector
creates a partial vacuum and so produces a powerful exhaust behind. Fig.
45 shows the mechanism of an injector. They are used for exhausting acid
fumes which would corrode metal fans and pipes, and for explosive dust
mixtures where fans are inadmissible.

[Illustration: FIG. 46.—Propeller Fan coupled to Electromotor (_Davidson
& Co., Ltd._)]

In the industries described in this book fans are most commonly used.
These are, in the main, wheels with two or more wing-shaped flattened
blades. Some are encased, others are open and fitted by means of annular
frames in the ducts according to the intended effect and kind of fan.
Fans are of two kinds, propeller and centrifugal, and, according to the
pressure they exert, of low, medium, or high pressure. They are now often
driven electrically, in which case there is advantage in coupling them
directly with the motor.

_Propeller fans_ have curved screw-shaped blades and are set at
right angles in the duct upon the column of air in which they act by
suction. The air is moved in the direction of the axis of the fan, and
generally it is possible, by reversing the action, to force air in
instead of extracting it. The draught produced is a low-pressure one
(generally less than 15 mm. of water). The current of air set in motion
travels at a relatively slow speed, yet such fans are capable, when
suitably proportioned, of moving large volumes of air. Propeller fans
are specially suitable for the general ventilation of rooms when the
necessary change of air is not being effected by natural means.

[Illustration: FIG. 47.—The Blackman (Belt-driven) Fan.]

_Centrifugal_ or _high-pressure fans_ (see figs. 48A and 48B) are always
encased in such a way that the exhaust ducts enter on one or both sides
of the axis. The air thus drawn in is thrown by the quickly rotating
numerous straight blades to the periphery and escapes at the outlet.
The centrifugal fan travels at a great speed, and the air current
has therefore great velocity and high pressure. When the pressure is
less than 120 mm. it is described as a medium, and when greater, a
high-pressure fan. For the former a galvanised iron casing suffices;
for the latter the casing requires to be of cast iron. Medium pressure
centrifugal fans are used to exhaust dust or fumes locally from the point
at which they are produced. They play a great part in industrial hygiene.

[Illustration: FIG. 48A.—‘Sirocco’ Centrifugal Fan]

[Illustration: FIG. 48B.—Showing exhaust aperture and fan blades]

High-pressure fans are used mainly for technical purposes, as, for
example, the driving of air or gas at high pressure. Localised
ventilation is needed to limit diffusion of dust and fumes, which
is attained in a measure also by separation of those workrooms in
which persons come into contact with poisonous materials from others.
Separation of workrooms, however, is not enough, as it is the individual
who manipulates the poison for whom protection is desired. To enclose or
hood over a dusty machine or fume-producing apparatus completely, or to
close hermetically a whole series of operations by complicated technical
arrangements, is only possible when no opening or hand feeding is
required. Dangerous substances can only be wholly shut in by substitution
of machinery for handwork.

[Illustration: FIG. 49.—Localised Exhaust Ventilation in a Colour Factory
(_Sturtevant Engineering Co., Ltd._)]

[Illustration: FIG. 50A.

FIG. 50B.

Ball Mills]

Where, however, absolute contact is unavoidable the dust or fume must
be carried away at its source. This is done by exhaust ventilation,
locally applied, in the following manner: A suitable hood or air guide
of metal or wood is arranged over the point where the dust is produced,
leaving as small an opening as possible for necessary manipulations. The
hood is connected with a duct through which the current of air travels.
An exhaust current dependent upon heat will only suffice in the case
of slight development of dust or fumes. As a rule exhaust by a fan is
necessary. Where exhaust ventilation has to be arranged at several
points all these are connected up by branch ducts with the main duct
and centrifugal fan. Where the ducts lie near the floor it is advisable
to fix adjustable openings in them close to the floor to remove the
sweepings.

[Illustration: FIG. 51.—Ventilated Packing Machine (_after Albrecht_)

_A_ Worm; _B_ Collector; _D_ Fan; _E_ Filter bag; _J_, _F_ Movable
shutters; _H_ Jolting arrangement]

It is important for the exhaust system of ventilation to be designed
in general so that the dust is drawn away from the face of the worker
downwards and backwards. Many horrible arrangements are found in which
the dust is first aspirated past the mouth and nose before it is drawn
into a hood overhead. The proportions of the branch pipes to the main
duct require to be thought out, and friction and resistance to the flow
must be reduced as far as possible by avoidance of sharp bends. Branch
pipes should enter the main duct at an angle of thirty degrees. A
completely satisfactory system requires very special knowledge and often
much ingenuity when the apparatus is complicated.

Disintegrators and edge runners can generally be covered in and the cover
connected with an exhaust. Ball mills, when possible, are best as the
rotating iron cylinder containing the steel balls and the material to be
pulverised is hermetically closed.

Powdered material can be carried mechanically from one place to another
by worms, screws, endless bands, or be driven in closed pipes by means
of compressed air. The inevitable production of dust in packing can be
avoided by the use of ventilated packing machines, which are especially
necessary in the case of white lead, bichromates, basic slag, &c.

[Illustration: FIG. 52.]

The difficulty is great in preventing dust in sieving and mixing, since
this is mainly done by hand. Still here, for example, by use of cases
with arm-holes and upper glass cover, injury to health can be minimised.
Benches with a wire screen and duct through which a downward exhaust
passes are useful in sorting operations (fig. 52).

Fig. 53 illustrates a grinding or polishing wheel fitted with localised
exhaust.

[Illustration: FIG. 53.—Removing Dust from Bobs and Mops (_James Keith
& Blackman Co., Ltd. By permission of the Controller of H.M. Stationery
Office_)]

To prevent escape of injurious gases all stills and furnaces must be kept
as airtight as possible and preferably under a slight negative pressure.
Agitators must be enclosed and should be fitted with arrangements for
carrying on the work mechanically or by means of compressed air and, if
necessary, exhaust ventilation applied to them. The aim should be to
enclose entirely drying and extracting apparatus.

[Illustration: FIG. 54.—‘Cyclone’ Separator (_Matthews & Yates, Ltd._)]

An important question remains as to what shall be done with the dust and
fumes extracted. In many cases they cannot be allowed to escape into
the atmosphere outside, and in the interests of economy recovery and
utilisation of the waste is the thing to aim at. This vital subject can
only receive barest mention here. The dust or fumes extracted require to
be subjected to processes of purification with a view to recovery of the
often valuable solid or gaseous constituents and destruction of those
without value.

[Illustration: FIG. 55A. FIG. 55B.

Dust-filter of Beth-Lübeck (_after Albrecht_)]

[Illustration: FIG. 56.—Dust-filter of Beth-Lübeck—Detail]

Collection of dust may take place in settling chambers as in a cyclone
separator in which the air to be purified is made to travel round the
interior of a cone-shaped metal receptacle, depositing the dust in its
passage (see fig. 54).

[Illustration: FIG. 57.—Arrangement for Precipitating Dust (_after
Leymann_)

_A_ Entry of dust laden air; _B_ Fan; _C_ Purified air; _D_ Pipe carrying
away water and last traces of dust; _E_ Worm carrying away collection of
dust.]

The most effective method, however, is filtration of the air through
bags of canvas or other suitable fabric as in the ‘Beth’ filter (see
figs. 55 and 56). In the ‘Beth’ filter a mechanical knocking apparatus
shakes the dust from the bag to the bottom of the casing, where a worm
automatically carries it to the collecting receptacle. In the absence of
mechanical knocking the filtering material becomes clogged and increases
the resistance in the system. Contrivances of the kind unintelligently
constructed become a source of danger to the workers. Dust of no value
is usually precipitated by being made to pass through a tower down which
a fine spray of water falls. If the gases and fumes can be utilised they
are either absorbed or condensed—a procedure of the utmost importance for
the protection of the workers.

Condensation of the gases into a liquid is effected by cooling and is
an essential part of all processes associated with distillation. The
necessary cooling is effected either by causing the vapours to circulate
through coils of pipes surrounded by cold water or by an increase in the
condensing surface (extension of walls, &c.), and artificial cooling of
the walls by running water.

Absorption of gases and fumes by fluids (less often by solid substances)
is effected by bubbling the gas through vessels filled with the absorbing
liquid or conducting it through towers (packed with coke, flints, &c.),
or chambers down or through which the absorbent flows. Such absorption
towers and chambers are frequently placed in series.

The material thus recovered by condensation and absorption may prove to
be a valuable bye-product. Frequently the gases (as in blast furnace gas,
coke ovens, &c.) are led away directly for heating boilers, or, as in the
spelter manufacture, to make sulphuric acid.




V

_PREVENTIVE REGULATIONS FOR CHEMICAL INDUSTRIES_


Sulphuric Acid Industry

(See also pp. 4-14 and 171)

Danger arises from escape of acid gases or in entering chambers, towers,
containers, &c., for cleaning purposes. The whole chamber system,
therefore, requires to be impervious and the sulphur dioxide and nitrous
gases utilised to their fullest extent—a procedure that is in harmony
with economy in production. The pyrites furnace must be so fired as to
prevent escape of fumes, which is best attained by maintenance of a
slight negative pressure by means of fans. The cinders raked out of the
furnace because of the considerable amount of sulphur dioxide given off
from them should be kept in a covered-in place until they have cooled.
Any work on the towers and lead chambers, especially cleaning operations,
should be carried out under strict regulations. Such special measures
for the emptying of Gay-Lussac towers have been drawn up by the Union
of Chemical Industry. Before removal of the sediment on the floor they
require a thorough drenching with water, to be repeated if gases are
present. Perfect working of the Gay-Lussac tower at the end of the
series of chambers is essential to prevent escape of acid gases. In a
well-regulated sulphuric acid factory the average total acid content of
the final gases can be reduced to 0·1 vol. per cent. Under the Alkali
Works Regulation Act of 1881 the quantity was limited to 0·26 per cent.
of sulphur dioxide—and this should be a maximum limit.

_Entering and cleaning out chambers and towers_ should only be done, if
practicable, by workmen equipped with breathing apparatus, and never
without special precautionary measures, as several fatalities have
occurred at the work. Towers, therefore, are best arranged so as to allow
of cleaning from the outside; if gases are noticed smoke helmets should
be donned. The same holds good for entering tanks or tank waggons. After
several cases of poisoning from this source had occurred in a factory the
following official regulations were issued:

    The deposit on the floor of waggons or tanks shall be removed
    either by flushing with water without entering the tank itself,
    or if the tank be entered the deposit is to be scooped out
    without addition of water or dilute soda solution.

    Flushing out shall only be done after the workmen have got out.

    Workmen are to be warned every time cleaning is undertaken that
    poisonous gases are developed when the deposit on the floor is
    diluted.

    Acid eggs, further, are to be provided with a waste pipe and
    manhole to enable cleaning to be done from outside.

The poisoning likely to arise is partly due to arsenic impurity
(development of arseniuretted hydrogen gas) in the sulphuric acid used.
Unfortunately arsenic free acid is very difficult to obtain.


Hydrochloric Acid—Saltcake and Soda Industries

(See also pp. 15-23 and 170)

Preventive measures here depend upon observance of the general principles
already discussed.

The _saltcake pan_ and reverberatory furnace require to be accurately and
solidly constructed and the process carefully regulated. Regulations
indeed were drawn up at an early date in England as to their working
to prevent escape of gases when adding the acid, raking over in the
reverberatory furnace, and withdrawal of the still fuming saltcake.

The following are the most important of these recommendations:

    The saltcake pan must not be charged when overheated.

    Sulphuric acid shall be added only after all the salt has been
    charged and the door shut.

    If hydrochloric acid fumes escape at the door when the Glover
    acid flows in the flow must be interrupted.

    All doors must be closed while work is in progress.

    Definite times shall be fixed for withdrawal of the saltcake in
    order to try and ensure that it be not still fuming, but should
    this be the case cold sulphate of soda shall be sprinkled over
    it.

The general principle should be observed of maintaining a slight negative
pressure in the furnace by insertion of a fan in the gas conduit so as to
avoid possible escape of gas. The fuming saltcake is best dealt with by
depositing it at once to cool in ventilated receptacles or chambers.

On grounds of economy and hygiene as complete an absorption as possible
of the hydrochloric acid gas developed in the saltcake and soda ash
process is to be aimed at, by conveying it through impervious conduits
to the bombonnes and lofty absorption tower filled with coke or flints
down which water trickles. The entire loss of hydrochloric acid should
not amount to more than 1·5 per cent. of the whole. Under the Alkali Act
at first 5 per cent. was allowed, but this is excessive now in view of
improved methods of condensation.

In the _Leblanc_ process the revolving furnace is on health grounds to
be preferred to the hand furnace. Such a furnace occupies the space
of but three hand furnaces and can replace eighteen of them. The vast
accumulation of waste, consisting mainly of calcium sulphide, and
generating sulphuretted hydrogen gas in such amount as to constitute
a nuisance, is only partially prevented by the Chance-Claus and other
methods of recovery, and makes it most desirable to adopt the Solvay
ammonia process.

_Note._—_Sulphonal, Oxalic acid, Ultramarine, Alum._—The production of
_sulphonal_ is intensely unpleasant owing to the disagreeable smell (like
cats’ excrement) of the mercaptan developed. All work therefore must be
carried on in air-tight apparatus under negative pressure and careful
cooling. Any escaping fumes must be absorbed in solution of acetone and
fine water spray.

Preparation of _oxalic acid_ unless carried on in closed-in vessels gives
rise to injurious and troublesome fumes. If open pans are used, hoods and
ducts in connection with a fan should be placed over them.

Grinding of _ultramarine_ and _alum_ requires to be done in closed-in
mills, and any dust drawn away by locally applied ventilation and
filtered. The gases given off in the burning process contain 3 per cent.
of sulphur dioxide, which requires to be absorbed—a procedure most easily
effected in towers where the upstreaming gas comes into contact with a
dilute solution of lime or soda.


Chlorine, Bleaching Powder, Chlorine Compounds

(See also pp. 23-9 and 173)

What has been said as to imperviousness of apparatus, negative pressure
maintained by the tall chimney stack or earthenware or fireclay fan,
&c., applies equally here. The exhaust ventilation is also required to
aspirate the gas into the bleaching chambers.

At the end of the system there must be either a tower packed with
quicklime to absorb the last traces of chlorine or such a number of
bleach chambers into which the gas can be led that no chlorine escapes.
Production of chlorine gas electrolytically is to be preferred to other
processes on hygienic grounds.

Careful cleanliness is the best prophylactic against occurrence of
_chlorine rash_ among persons employed in the electrolytic production of
chlorine. In some factories attempt has been made to use other substances
(magnetite) instead of carbon for the anode, and the success attending
their adoption is further proof that the tar cement at the anode helped
to cause the acne.

In the _Weldon_ process care must be taken that the water lutes are
intact, and the stills must not be opened before the chlorine has been
drawn off. All processes in which manganese dust can arise (grinding
of manganese dioxide and drying of Weldon deposit) should be done
under locally applied exhaust. The _bleaching powder_ chambers must be
impervious and care taken that they are not entered before the chlorine
has been absorbed. Usually the number of lime chambers connected up with
each other is such that no chlorine escapes free into the air. Emptying
of the finished product should not be done by hand, as considerable
quantities of chlorine escape and make the work extremely irksome.
Mechanical methods of emptying should be adopted in substitution for hand
labour, and of these the Hasenclever closed-in apparatus is the best.


Nitric Acid and Explosives

(See also pp. 39-49 and 172)

In the production of _nitric acid_ complete imperviousness of the system
and as complete condensation of the gases as possible by means of
tourilles, cooling condensers, and the requisite number of towers are
necessary. The method suggested by Valentine of manufacture of nitric
acid in apparatus under a partial vacuum has advantages from a hygienic
standpoint. Earthenware fans are used to force the nitric acid gases
onwards and have the advantage of creating a negative pressure. Great
care is needed in handling, emptying, packing, conveying, and storing the
acid in consequence of the danger from breaking or spilling. The bottles
used must be in perfect condition and must be well packed. No greater
stock of nitric acid should be allowed in a room than is absolutely
necessary, and care must be exercised in the event of a carboy breaking
that the spilt acid does not come into contact with organic substances,
as that would increase development of nitrous fumes.

Workers must be warned not to remain in rooms in which acid has been
spilt. They are only to be entered by workers equipped with breathing
apparatus (smoke helmets).

Among the special regulations on the subject may be mentioned those
of the Prussian Ministerial Decree, dated January 8, 1900, concerning
nitrous fumes and means of protection for workers employed with the acid.
What has been said on p. 257 in regard to the transport of sulphuric acid
applies equally to nitric acid.

In the _nitrating_ process in the manufacture of explosives (see p.
47) it is essential that the apparatus is hermetically closed, that
agitation is done mechanically, or better still by means of compressed
air, and that any fumes developed are exhausted and condensed. In the
preparation of _nitro-glycerin_ (see p. 46) the gases developed in the
nitration of the waste acid require to be carefully condensed. Contact
of nitro-glycerin with the skin has to be avoided and the attention
of the workers drawn to the danger. Preparation of _gun cotton_ (see
p. 48) takes place in machines which are at the same time nitrating
and centrifugalising machines. The apparatus is first filled with
the nitrating acid and the cotton added; the fumes are drawn off by
earthenware ducts and fans, and lastly the bulk of the acid is removed by
centrifugal action. Such machines carry out effectually the principles of
industrial hygiene.

In the preparation of _fulminate of mercury_ nitrous fumes, cyanogen
compounds, and acetic acid compounds are developed by the action of
the nitric acid on mercury, and require to be dealt with by exhaust
ventilation.[G]


Artificial Manures, Fertilizers

(See also pp. 53 and 54)

In grinding phosphorite and superphosphates, corrosive dust is produced.
All grinding operations must, therefore, be carried out automatically
in closed apparatus (ball mills, disintegrators, &c.). In making the
phosphorite soluble by treatment with sulphuric acid, and subsequent
drying of the product, corrosive hydrofluoric acid gas is developed,
which requires to be carried away by an acid proof exhaust fan, and
condensed in a tower by water (see fig. 58). The modern revolving drying
machines are especially serviceable.

[Illustration: FIG. 58.—Washing tower for hydrofluoric acid (_after
Leymann_.)]

In the production of _basic slag_ corrosive dust is given off, causing
ulceration of the mucous membrane. Grinding and other manipulations
creating dust must be carried on in apparatus under local exhaust
ventilation. The following—somewhat shortened—are the German Imperial
Regulations, dated July 3, 1909, for basic slag factories.

    BASIC SLAG REGULATIONS

    1. Workrooms in which basic slag is crushed, ground, or stored
    (if not in closed sacks) shall be roomy and so arranged as to
    ensure adequate change of air. Floors shall be of impervious
    material allowing of easy removal of dust.

    2. Preliminary breaking of the slag by hand shall not be done
    in the grinding rooms, but either in the open air or in open
    sheds.

    3. Slag crushers, grinding mills, and other apparatus shall be
    so arranged as to prevent escape of dust as far as possible
    into the workrooms. They shall be provided with exhaust
    ventilation and means for collecting the dust if this cannot be
    done in the absence of dust.

    4. Arrangements shall be made whereby barrows conveying
    material to the grinding mills shall be emptied directly into
    partially hooded hoppers provided with exhaust ventilation so
    as to prevent escape of dust into the workrooms.

    5. The casing and joints of the grinding mills, ducts, dust
    collectors and sieves shall be airtight; if leaks are noticed
    they must be repaired forthwith.

    6. Ducts, dust collectors and sieves shall be so arranged as to
    enable periodical cleansing to be undertaken from the outside.

    7. Repairs of the plant mentioned in Para. 5 in which workers
    are exposed to inhalation of slag dust shall be entrusted by
    the occupier only to such workers as wear respirators supplied
    for the purpose or other means of protecting mouth and nostrils
    such as wet sponges, handkerchiefs, &c.

    8. Emptying of slag powder from the grinding mills and dust
    collectors and transference to the store rooms shall only
    be done in accordance with special regulations designed to
    minimise dust.

    9. Filling slag powder into sacks from the outlets of the
    mills, elevating and discharging it into receptacles shall only
    be done under efficient exhaust ventilation.

    10. Sacks in which the powder is transported and piled in heaps
    shall be of a certain defined strength to be increased in the
    case of sacks to be piled in heaps more than 3½ metres in
    height. Special rooms separated from other workrooms shall be
    provided for storage of slag powder in sacks. Only the sacks
    representing the previous day’s production may be stored in the
    grinding rooms.

    Basic slag in powder and not in sacks shall be kept in special
    storage rooms shut off entirely from other workrooms. No person
    shall enter such storage rooms when they are being filled or
    emptied. Discharging the contents of the sacks into them shall
    be done under exhaust ventilation.

    11. The floors of the workrooms described in Para. 1 shall be
    cleaned before the commencement of each shift or in an interval
    during each shift. No person except those engaged in cleaning
    shall be present during the operation. If cleaning is effected
    by sweeping, the occupier shall require the persons doing it to
    wear the respirators provided or other protection for the mouth
    and nose.

    12. The occupier shall not permit the workers to bring spirits
    into the factory.

    13. A lavatory and cloakroom and, separated from them and in
    a part of the building free from dust, a meal room shall be
    provided. These rooms shall be kept clean, free from dust, and
    be heated during the winter.

    In the lavatory and cloakroom water, soap, and towels shall be
    provided and adequate arrangements shall be made for keeping
    the clothing taken off before commencing work.

    The occupier shall give the persons employed opportunity to
    take a warm bath daily before leaving work in a bathroom
    erected inside the factory and heated during the winter.

    14. No woman or male young person under eighteen years of age
    shall work or remain in a room into which basic slag is brought.

    Persons under eighteen years of age shall not be employed in
    beating sacks which have contained basic slag.

    15. No person employed in breaking or grinding, emptying,
    packing, or storing basic slag, shall work more than ten hours
    daily.

    There shall be intervals during working hours amounting in the
    aggregate to two hours, one of them lasting at least an hour.
    If duration of employment daily is limited to seven hours with
    never longer than four hours’ work without an interval, only
    one interval of at least one hour is required.

    16. For work mentioned in Para. 15 no person shall be employed
    without a certificate from an approved surgeon stating that he
    is free of disease of the lungs and not alcoholic. The occupier
    shall place the supervision of the health of the workers under
    a surgeon who shall examine them at least once a month for
    signs of disease of the respiratory organs and alcoholism.
    Workers engaged in the operations mentioned in Para. 15 shall
    be suspended from employment when the surgeon suspects such
    illness or alcoholism. Those showing marked susceptibility to
    the effect of basic slag dust shall be permanently suspended.

    17. A health Register shall be kept in which shall be entered
    the precise employment, duration of work, and state of health
    of the persons employed.

    18. The occupier shall obtain a guarantee from the workers that
    no alcohol or food shall be taken into the workrooms.


Preparation of Hydrofluoric Acid

(See also pp. 37 and 171)

The fumes given off in the preparation of hydrofluoric acid require to be
collected in leaden coolers and vessels; that which escapes requires to
be absorbed by a water spray in towers. The apparatus must be impervious
and kept under a slight negative pressure.


Chromium Compounds

(See also pp. 55-8 and 185)

The German Imperial Decree, dated May 16, 1907, contains the preventive
measures necessary in bichromate factories. According to this, workers
suffering from ulceration of the skin (chrome holes, eczema) are not to
be employed except on a medical certificate that they are free from such
affections, and daily examination for signs of ulceration is enjoined,
so that those affected may receive prompt treatment. Further, periodical
medical examination of the workers is required at monthly intervals.
Respirators (for work in which dust cannot be avoided), with lavatory,
cloakroom, and meal room accommodation, are to be provided, and also
baths. In handling bichromates wearing of impervious gloves may be
necessary, and smearing the hands and face with vaseline is recommended.
In addition diffusion of dust and fumes must be minimised; machines
in which mixing, crushing, and grinding are done must be impervious,
and provided with exhaust ventilation. Charging of the furnaces, where
possible, should be effected mechanically and the fumes developed both in
manipulation of the furnaces and from hot bichromate liquor removed by an
exhaust.

A leaflet containing directions for workers coming into contact with
chromium compounds in chemical factories, dyeing, tanning, wood staining,
calico printing, wall paper printing, painting, &c., has been drawn up by
Lewin. It contains a list of the poisonous chrome compounds and of the
industries in which chrome poisoning occurs, information as to the action
of chrome upon the skin and mucous membrane, and the preventive measures
necessary. Among the last named are: smearing the skin with oil, use of
impervious gloves, respirators in work where dust arises, necessity of
cleanliness, and periodical medical examination.

For the _chrome tanning industry_ the following leaflet was drawn up
by the Imperial Health Office in Berlin, which succinctly states the
measures against chrome poisoning in these industries and contains much
practical information for the workers:

    In chrome tanning by the two bath process, the first bath
    containing potassium bichromate and hydrochloric acid has a
    corroding effect upon broken surfaces of the skin (scratches,
    chapped hands, eruptions, &c.). In consequence, they develop
    into round ulcers (chrome holes) with hard raised edges which
    are difficult to heal and go on increasing in size unless work
    at the process is temporarily given up. In persons with very
    sensitive skin, even though the surface may be intact, handling
    the liquor brings on sometimes an obstinate rash (eczema) on
    the hands and forearms.

    The solution used in the one bath process has no corrosive
    action, but it is a strong poison, just as is the solution of
    potassium bichromate of the two bath process. If swallowed, the
    solutions cause vomiting, diarrhœa, kidney trouble, and even
    death. Chromium compounds can also enter the body through skin
    wounds and cause illness.

    _Prevention._—In order to prevent the occurrence of chrome
    ulceration, workers employed with chrome or chrome solutions
    must be especially careful in avoiding injury to the skin of
    the hands or forearms. This applies especially to workers who
    carry the vessels containing bichromate, who weigh and dissolve
    the potassium bichromate, or who come into contact with the
    tanning liquor or with undressed skins and hides which have
    lain in the liquor.

    If, in spite of precautions, eruptions, rashes, or ulceration
    occur, all work necessitating contact with corrosive tanning
    liquors should be suspended until they are healed.

    In order to reduce risk of action of the liquor on the skin,
    workers employed in the process described would do well if,
    before commencing work, they carefully smeared hands and
    forearms with unsalted lard, vaseline, or the like, and during
    work avoided, as much as possible, soiling the bare hands and
    arms with the liquor.

    If, nevertheless, a worker has contracted a chrome hole, or
    eruption, he should consult a medical man, informing him at the
    same time of the nature of his work.

    To avoid internal absorption of chrome, workers preparing the
    baths must carefully avoid inhaling the dust of chromium salts.
    These and all other workers engaged with the liquors containing
    chromium must not take food and drink while at work. Working
    suits should be taken off and face and hands washed with soap
    before eating or drinking, and before leaving the factory.


Petroleum, Benzine

(See also pp. 59-64 and 222-4)

As crude petroleum and the higher fractions first distilled from it
affect the skin injuriously, wetting the skin should be avoided, and
careful cleanliness on the part of the workers enjoined. Workers exposed
to the influence of gases escaping from naphtha springs and wells should
be equipped with breathing apparatus (smoke helmets); this applies to
those who have to enter stills and other apparatus connected with the
distillation of petroleum.

In the preparation of petroleum by sulphuric acid sulphur dioxide in
great quantity is developed, constituting a distinct danger to the
workers. This process, therefore, should be carried on in closed vessels
furnished with mechanical stirrers or compressed air agitators. The most
suitable apparatus is that illustrated in fig. 13.

Petroleum tanks must be thoroughly aired before they are cleaned and
should be entered only by workers equipped with breathing apparatus.
Apparatus containing petroleum and benzine requires, as far as possible,
to be closed in and air tight (as, for example, in the extraction of fat
from bones and oil seed, in the rubber industry, and in chemical cleaning
establishments); where benzine fumes develop they should be immediately
drawn away by suitably applied exhaust ventilation. This is necessary, on
account of the danger of fire, in chemical cleaning establishments where
purification is effected by means of benzine in closed drums.

Regulations for benzine extraction plants are contained in the Prussian
Ministerial Decree, dated January 5, 1909, for benzine extraction
works, and also in that of August 3, 1903, for dry-cleaning premises,
to which last were added ‘Directions for safety,’ containing important
regulations as to risk from fire. From our standpoint the following
points are of interest: care is to be taken to provide and maintain
exhaust ventilation directly across the floor. The air, however, must
not be allowed to pass near any fire. Drying rooms especially are to be
lofty and airy, and separated from other workrooms. In factories with
mechanical power the authorities may require provision of artificial
ventilation for the drying rooms. Washing machines, centrifugalising
machines, and benzine rinsing vessels should be furnished with
well-fitting covers to be removed only for such time as is absolutely
necessary for putting in and taking out the articles to be cleaned,
shaken, or rinsed. The vessels named are to be examined as to their
imperviousness at least once every quarter by a properly qualified
person. The condition in which they are found is to be noted in a book to
be shown to the Factory Inspector and police authorities on demand.

Lastly, substitution for benzine of other less poisonous substances such
as carbon tetrachloride has been urged.


Phosphorus, Lucifer Matches

(See also pp. 49-53 and 190)

In view of the danger of the lucifer match industry, measures were
taken at an early date in almost all civilised states to guard against
phosphorus poisoning, and in many countries have led to the prohibition
of the use of white phosphorus. Complete prohibition of its manufacture
and use was first enacted in Finland (1872) and in Denmark (1874).
Prohibition was decreed in Switzerland in 1879 (in January 1882 this was
revoked, but again enacted in 1893), and in the Netherlands in 1901. In
Germany the law prohibiting the use of white phosphorus came into force
in January 1908, and runs as follows:

    1. White or yellow phosphorus shall not be employed in the
    production of matches and other lighting substances. Lighting
    substances made with white phosphorus shall not be kept for
    sale, or sold, or otherwise brought on the market. Provided
    that this shall not apply to ignition strips which serve for
    the lighting of safety lamps.

    2. Persons wilfully infringing this law shall be punished
    by a fine of 2000 marks. If the infringement occurs through
    ignorance the fine shall consist of 150 marks.

    In addition to the fine, all prohibited articles produced,
    imported, or brought into the trade shall be confiscated,
    as well as the implements used in their production, without
    reference to whether they belong to the person convicted or
    not. If prosecution or conviction of the guilty party cannot be
    brought home, confiscation nevertheless is to be carried out
    independently.

Roumania and France have a state monopoly of matches; in these states
no white phosphorus matches have been produced since 1900 and 1898
respectively. France, by the Law of December 17, 1908, signified
concurrence with the International Convention in regard to the
prohibition of the use of white phosphorus.

In Sweden and Norway the prohibition of white phosphorus is in force
only for the home trade. A Swedish Decree, dated December 9, 1896,
permitted factories carrying on the manufacture for export to use white
phosphorus, and almost precisely similar provisions are contained in the
Norwegian Decree. The Swedish Decree, dated March 30, 1900, permits white
phosphorus matches to be exported, but not to be sold in the country. In
Austria difficulties in regard to prohibition of white phosphorus arose
owing to trade conditions (especially in the East), and the attitude of
the states competing in the lucifer match trade, particularly Italy and
Japan. Austria, therefore, made agreement with international prohibition
of white phosphorus, dependent on the attitude of Japan; since Japan did
not concur, the decision of Austria fell through. When, however, Italy in
the year 1906 joined the Convention, the difficulties were also overcome
in Austria, and by a law similar to that of Germany, dated July 13, 1909,
prohibition of the manufacture and sale of white phosphorus matches dates
from the year 1912.[H]

Belgium has refrained from prohibition of white phosphorus, but on the
other hand has passed a series of enactments relating to the match
manufacture, of which the most essential are here cited, since they
characterise the measures which come into consideration for factories in
which white phosphorus is still employed.

    _Royal Decree, dated March 25, 1890, modified by the Royal
    Decree, dated February 12, 1895, and November 17, 1902,
    concerning employment in lucifer match factories._

    1. In match factories where white phosphorus is used, mixing
    the paste and drying the dipped matches shall be carried on in
    a place specially set apart for the purpose.

    2. Mixing the paste shall be carried on in an entirely closed
    vessel or in one connected with an efficient exhaust draught
    locally applied.

    The proportion of white phosphorus in the paste shall not
    exceed in weight 8 per cent. of the total material, not
    including water.

    3. Hoods and ducts communicating with an exhaust draught shall
    be installed at the level of the plates for dipping white
    phosphorus matches, and over the vessels containing the paste.

    4. Drying rooms for white phosphorus matches, if entered by the
    workers, shall be mechanically ventilated.

    5. Rooms in which phosphorus fumes can arise shall be lofty and
    well ventilated, preferably by an exhaust at the level of the
    work benches, communicating with the main chimney stack.

    The workrooms shall be kept clean. No food or drink shall be
    taken in them.

    6. In every match factory the workers shall have at their
    disposal a special cloak room and suitable and sufficient
    washing accommodation, so as to be able to change clothes
    before commencing, and at the end of, work, and to wash the
    hands and face on leaving.

    Cleanliness will be obligatory upon the workers manipulating
    phosphorus paste or matches.

    7. Workers coming into contact with phosphorus paste or matches
    shall be examined monthly by a surgeon appointed by the
    Minister of Industry, who shall be paid by the occupier.

    Workers having decayed, unstopped teeth, or exhibiting symptoms
    of gingivitis or stomatitis, or in poor health at the time of
    examination, shall be temporarily suspended from work.

    The surgeon shall enter the results of his monthly examinations
    in a prescribed register.

    This register shall be shown to the Factory Inspector on demand.

These decrees are supplemented by further orders regarding the taking of
samples of paste in match factories and store houses (Royal Orders of
March 25, 1890; February 12, 1895; April 18, 1898; November 17, 1902).

As is evident from the Belgian enactment, in states where prohibition of
white phosphorus is not in force, palliative measures only are possible
and even then they can only be enforced in large factories when automatic
machinery is used to eliminate hand labour in dangerous operations. In
this respect the introduction of closed, ventilated, mechanical mixing
apparatus provided with mechanical stirrers, closed and ventilated
mechanical dipping and drying apparatus, are especially important.
Certain modern American machines carry through the whole complicated
process of the phosphorous match industry automatically. Seeing that
prohibition of white phosphorus is an accomplished fact and that matches
free from risk in their manufacture answer every purpose, the universal
enforcement of the prohibition of white phosphorus should be striven for
in civilised states.


Carbon bisulphide

(See also pp. 68-71 and 193-5)

Use of carbon bisulphide in the vulcanising of indiarubber goods by
dipping them into the liquid and subsequently drying them (usually in
a current of hot air) causes development of carbon bisulphide fumes in
considerable quantity, especially if the articles to be dried are laid
on shelves or hung up in the workroom, a procedure which should never be
permitted. Drying must be carried out under local exhaust ventilation.

All vessels holding carbon bisulphide used for dipping can be placed in
a wooden channel above the dipping vessels, provided with openings for
manipulation, and connected with an exhaust system.

The following are the German Imperial Regulations, dated March 1, 1902,
for vulcanising of indiarubber by means of carbon bisulphide:

    VULCANISING BY MEANS OF CARBON BISULPHIDE

    (Notice concerning the erection and management of industrial
    premises in which indiarubber goods are vulcanised by means of
    carbon bisulphide or chloride of sulphur.)

    The following regulations shall apply in accordance with
    paragraph 120 (_e_) of the Industrial Code:

    1. The floor of such rooms as are used for the vulcanising
    of indiarubber goods by means of carbon bisulphide shall not
    be lower than the surrounding ground. The rooms shall have
    windows opening into the outer air, and the lower halves shall
    be capable of being opened so as to render possible sufficient
    renewal of air.

    The rooms shall be ventilated by fans mechanically driven. With
    the approval of the higher authorities permission to dispense
    with mechanical draught may be allowed, provided that in other
    ways powerful change of air is secured. With the approval of
    the higher authorities special ventilating arrangements can be
    dispensed with if the fumes of carbon bisulphide are removed
    immediately, at the point where they are produced, by means
    of a powerful draught, and in this way purity of the air be
    secured.

    2. The vulcanising rooms shall not be used as a dwelling, or
    for sleeping in, or for preparing food in, or as a store,
    or drying room, nor shall other processes than those of
    vulcanising be carried on in them. No persons, except those
    engaged in vulcanising processes, shall be allowed in the rooms.

    There shall be at least 20 cubic meters (700 cubic feet) of air
    space allowed for each person employed therein.

    3. Only such quantities of carbon bisulphide shall be brought
    into the vulcanising rooms as shall serve for the day’s supply.
    Further storage shall be made in a special place separate from
    the workrooms. Vessels to hold the vulcanising liquid shall be
    strongly made, and when filled and not in use shall be well
    covered.

    4. Vulcanising and drying rooms shall be warmed only by steam
    or hot-water pipes.

    These rooms shall be lighted only by means of strong
    incandescent electric lamps.

    Exceptions from paragraphs 1 and 2 may be allowed by the higher
    authorities.

    5. Machines intended for vulcanising long sheets of cloth shall
    be covered over (_e.g._, with a glass casing) so as to prevent
    as far as possible the entrance of carbon bisulphide fumes into
    the workrooms, and from the casing the air shall be drawn away
    effectually by means of a fan mechanically driven. Entrance to
    the space which is enclosed shall only be allowed in case of
    defects in the working.

    In cases where a covering of the machine is not practicable
    for technical reasons the higher authorities can, if suitable
    means of protection are used (especially when the machine is
    placed in an open hall, and provided that no person works at
    the machine for more than two days a week), allow of exception
    to the above arrangement.

    6. Vulcanising of other articles (not mentioned in par. 5),
    unless carried out in the open air, shall be done in covered-in
    boxes into which the worker need only introduce his hands, and
    so arranged as to keep the fumes away from the face of the
    worker.

    The air must be drawn away from the box by means of a powerful
    draught.

    7. Rule 6 shall apply in vulcanising both the outside and
    inside of indiarubber goods. In vulcanising the inside no
    worker shall be allowed to suck the fluid through with the
    mouth.

    8. The goods after their immersion in the vulcanising fluid
    shall not lie open in the room, but shall either be placed
    under a ventilated cover or at once be carried into the drying
    chamber.

    The drying chamber or drying rooms in which the wares are
    exposed to artificial heat immediately after vulcanising
    shall be so arranged that actual entrance into them for the
    putting in or taking out of the vulcanised goods shall not
    be necessary. No person shall be allowed to enter the drying
    chamber while work is going on. The higher authorities can
    permit of exceptions to this rule in the case of the drying of
    long rolls if sufficient protecting arrangements are made.

    9. When vulcanisation is effected by means of chloride of
    sulphur the vessels or chambers used for holding it shall be so
    arranged that escape of the fumes is prevented.

    No person shall enter the vulcanising chamber until the air in
    the chamber has been completely changed; it shall not be used
    for purposes other than vulcanising.

    10. Employment in vulcanising with carbon bisulphide or in
    other work exposing the workers to carbon bisulphide vapour
    shall not be allowed without a break for more than two hours
    and in no case for more than four hours in one day; after two
    hours a pause of at least one hour must be allowed before
    resumption.

    No person under 18 years of age shall be employed.

    11. The occupier shall provide all workers employed in work
    mentioned in paragraph 10 with proper and sufficient overalls.
    By suitable notices and supervision he shall see that when not
    in use they are kept in their proper place.

    12. Separate washing accommodation and dressing-rooms for each
    sex shall be provided, distinct from the workrooms, for all
    persons employed as stated in paragraph 11.

    Water, soap, and towels and arrangements for keeping the
    clothes put off before the commencement of work shall be
    provided in sufficient amount.

    13. The occupier shall appoint a duly qualified medical
    practitioner (whose name shall be sent to the Inspector of
    Factories) to supervise the health of those exposed to the
    effects of carbon bisulphide. He shall examine the workers once
    every month with a view to the detection of poisoning by carbon
    bisulphide.

    By direction of the medical practitioner workers showing signs
    of carbon bisulphide poisoning shall be suspended from work
    and those who appear peculiarly susceptible shall be suspended
    permanently from work in processes mentioned in paragraph 10.

    14. The occupier shall keep a book, or make some official
    responsible for its keeping, of the changes in the personnel in
    the processes mentioned in paragraph 10 and as to their state
    of health. The book shall contain—

      (1) The name of the person keeping the book;

      (2) The name of the appointed surgeon;

      (3) Surname, Christian name, age, residence, date of first
      employment, and date of leaving of every worker mentioned in
      paragraph 10, and the nature of the employment;

      (4) The date of any illness and its nature;

      (5) Date of recovery;

      (6) The dates and results of the prescribed medical examination.

    15. The occupier shall require the workers to subscribe to the
    following conditions:—

      No worker shall take food into the vulcanising rooms;

      The workers shall use the protection afforded in paragraphs 5-7
      and use the overalls in the work named;

      The workers shall obey the directions of the occupier given in
      accordance with Rule 5, paragraphs 1 and 2, Rule 8, paragraphs
      1 and 2, and Rule 9, paragraph 2. Workers contravening these
      orders shall be liable to dismissal without further notice.

      If in a factory regulations already exist (paragraph 134(a) of
      the Industrial Code) the above shall be included.

    16. In the vulcanising rooms mentioned in Rule 1 there shall be
    posted up a notice by the police stating—

      (_a_) The cubic capacity of the rooms;

      (_b_) The number of workers who may be employed.

    Further, in every vulcanising room there shall be posted up in
    a conspicuous place and in clear characters Rules 1-15 and the
    conditions in paragraph 15.

Reference should be made also to the Prussian Ministerial Decree, dated
February 23, 1910, on the preparation, storing, and manufacture of carbon
bisulphide, and to the French Ministerial Circular, dated January 20,
1909 (Manufacture of Indiarubber).

Employment of benzine and chloride of sulphur for vulcanising is, from a
hygienic standpoint, to be preferred to that of the much more dangerous
carbon bisulphide. The same applies also to the process of the extraction
of fat.

In the references made to general arrangements for the protection of
workers dealing with poisons, stress was laid on the complete enclosing
of extraction apparatus. This applies, of course, to extraction by means
of carbon bisulphide, both on grounds of economy, health, and risk from
fire.

On account of the risk to health, efforts have been made to substitute
other means of equal efficiency, free from danger. Such a substitute may
be found in _carbon tetrachloride_. This extracts well, and dissolves
grease spots (like benzine), is not explosive, is scarcely inflammable,
and is less poisonous than the substances commonly used for extraction.
Its employment is to be recommended on hygienic grounds, but the
relatively high price may stand in the way of its use.


Illuminating Gas Industry. Production of Tar and Coke

(See also pp. 71-90 and 199)

In illuminating gas factories imperviousness of the whole working system
is especially important from an economical and hygienic standpoint,
since only in this way can danger to the working staff be avoided. This
applies especially to the retorts, from which no gas should be allowed
to escape. If the exhaust is working satisfactorily this should not be
possible, as the pressure of the gas in the retorts during distillation
will be a negative one. Correct regulation of pressure is thus of the
greatest importance in the prevention of poisoning in gas works.

Further, special precaution is necessary in operations with gas purifying
material containing cyanogen, since otherwise the workers suffer from the
gases developed from the gas lime.

Work with gas purifying material should be so arranged that injurious
gases are carried away by suitable ventilating arrangements.
Consideration for the neighbourhood forbids their discharge into the open
air, and forbids also operations with the gas purifying material in the
open air; therefore non-injurious removal of these gases is necessary.

Quenching of the coke also should, on account of the annoyance to the
working staff and to lessen nuisance to the neighbourhood, be carried out
so that the fumes are drawn into the main chimney stack.

In coke ovens escape of tarry constituents and of poisonous emanations
are prevented by imperviousness of the apparatus, by sufficiency of the
exhaust draught, and especially by passing the products of distillation,
which cannot be condensed, under a fire, or by absorbing them either with
water or oil.

Special precautionary measures are needed further in the distillation of
the washing oil, and generally escape of poisonous emanations must be
prevented by the greatest possible imperviousness of the distillation
system and corresponding regulation of pressure.


Gas Motors (Power Gas Stations)

(See also pp. 80-5)

The following points, taken from an Austrian Ministerial Decree (dated
December 2, 1903), for the prevention of poisoning in power gas works,
may be useful:

    POWER GAS INSTALLATIONS

    In mixed gas installations (Dowson, water gas) of the older
    system, the way in which the gas is produced causes the whole
    apparatus and pipes to be under slight negative pressure,
    because the steam required for the process must be blown into
    the generator. In these works, therefore, a small special steam
    boiler is required and a gas receiver to store the gas.

    In more modern suction generator gas installations the piston
    is used to suck in steam and air as well as the gases arising
    in the generator and to draw them into the motor cylinder. Thus
    the whole system is kept in a condition of slight negative
    pressure during the process. While the suction generator gas
    system is working, only so much gas is produced as the motor
    uses for the time being, so that with this system there is no
    greater store of gas than is requisite.

    In such an installation the following rules should be borne in
    mind:

    1. All the apparatus (gas pipes, valves, &c.) must be
    constructed and maintained in a completely impervious
    condition. Any water seals especially which may be in use must
    receive attention.

    2. Precautions must be taken to prevent the gases from the
    generator passing into the coolers and purifiers when the
    engine is at rest.

    3. Care is to be taken when the apparatus is at rest to prevent
    any possible subsequent escape of gas into the room where the
    apparatus is installed.

    4. The return of explosive gas out of the gas engine into the
    gas pipe by failure to ignite or other accident, must be made
    impossible.

    5. The apparatus through which the generator is charged must
    possess a tightly fitting double valve to prevent escape of gas
    into the room during charging.

    6. The pipes for conducting away the unpleasantly smelling
    bituminous constituents in the water mixed with sulphuretted
    hydrogen from the scrubbers must not communicate with the
    workroom.

    7. Precautions must be taken to minimise the danger during the
    cleaning of the generator (removal of ashes and slag).

    8. All stop-cocks and valves are to be so arranged that their
    position at any time (open or shut) is clearly visible from
    outside.

    9. Purifiers with a capacity greater than two cubic meters
    must be provided with appliances which make possible thorough
    removal of the gas before they are opened.

    10. The gas washing and cleaning apparatus and pipes are to be
    fitted with gauges indicating the pressure existing in them at
    any moment.

    11. When a suction gas plant is first installed and also at
    times when there is no gas in the pipes and plant between the
    generator and the engine, gas must be blown in until all air is
    expelled before the engine is set going.

    12. During the cleaning of apparatus and pipes which, when in
    action, contain gas, the rooms must be thoroughly ventilated.

    13. Rooms in which suction gas plant is installed must be of
    such a height that all the plant and its connections can be
    easily reached for cleaning, &c., and be capable of such free
    ventilation as to render impossible an accumulation of gas.

    14. These rooms must be separated from living rooms by a wall
    without any openings in it. Emanations also must be prevented
    as far as possible from entering into living or working rooms
    situated over the gas engine.

    15. Erection of apparatus for generating and purifying suction
    gas in cellars shall only be allowed if specially effective
    ventilation is provided by natural or mechanical means.

Other Regulations are those of the Prussian Ministerial Decree, dated
June 20, 1904, as to the arrangement and management of suction gas
premises.


ACETYLENE GAS INSTALLATIONS

(See also pp. 85-7)

The following regulations for the protection of workers in acetylene gas
installations are taken from the Prussian Ministerial Decree, dated 2
November, 1897:

    1. Preparation and condensation of acetylene on the one hand,
    and liquefaction on the other, must be carried on in separate
    buildings.

    2. If the pressure employed for condensation of the gas exceeds
    eight atmospheres, this work must take place in a room set
    apart for the purpose.

    3. Rooms in which acetylene is prepared, condensed, or
    liquefied shall not be used as, nor be in direct connection
    with, living rooms. They must be well lighted and ventilated.

    4. The carbide must be kept in closed watertight vessels, so
    as to ensure perfect dryness and only such quantities shall
    be taken out as are needed. The vessels must be kept in dry,
    light, well-ventilated rooms; cellar rooms may not be used for
    storage purposes.

    5. Crushing of carbide must be done with the greatest possible
    avoidance of dust. Workers are to be provided with respirators
    and goggles.

    6. Acetylene gasometers must be fitted up in the open air or in
    a well-ventilated room, separated from the gas generator. Every
    gas receiver must have a water gauge showing the pressure in
    the receiver.

    7. Between the gasometer and receiver a gas purifier must be
    provided so as to remove impurities (phosphoretted hydrogen,
    arseniuretted hydrogen, carbon bisulphide, ammonia, &c.).

    8. Condensation of acetylene gas at a pressure exceeding ten
    atmospheres shall only be done in combination with cooling.


DISTRIBUTION AND USE OF POWER AND ILLUMINATING GAS

The Austrian Gas Regulations (of July 18, 1906) contain general
provisions as to impermeability and security of the gas pipes and the
precautions to be observed in their installation. Special directions
follow as to main flues, material, dimensions, branches, and connections,
valve arrangements, testing of the pipes against leakage, directions
for discovering leaks, and other defects; also the nature of the branch
pipes (dimensions and material), valves, cocks, syphons, water seals, and
pressure gauges. In addition there are directions as to testing pipes and
how to deal with escape of gas, freezing of pipes, and other mishaps.


Ammonia

(See also pp. 90-3 and 175)

In the production of ammonia and ammonium salts (ammonium sulphate)
combination of the ammoniacal vapour with the sulphuric acid is
accompanied with the formation of volatile dangerous gases containing
sulphuretted hydrogen and cyanogen compounds, which produce marked
oppression and sometimes endanger the health of the workers. Drawing-off
these fumes into the furnace (practised sometimes in small industries)
is not advisable, as the sulphuretted hydrogen is burnt to sulphur
dioxide; if it is burnt absorption of the sulphur dioxide should follow,
or working it up into sulphuric acid (Leymann). Often these gases are
freed from cyanogen compounds and sulphuretted hydrogen by means of gas
purifying materials, such as are used in gas works. The whole apparatus
must be impervious. Where liquids containing ammonia are used exhaust
ventilation is necessary.


Cyanogen, Cyanogen Compounds

(See also pp. 93-5 and 195-7)

Processes in which cyanogen gas can develop, require to be done under a
powerful exhaust draught.

In the production of cyanogen compounds possibility of the escape of
hydrocyanic acid (prussic acid) has to be borne in mind. Such escape is
possible in its production from raw animal products.

The most careful cleanliness and observance of general measures for
personal hygiene are necessary in factories in which cyanogen compounds
are manufactured or handled. In crushing cyanide of potassium the workers
should wear indiarubber gloves and respirators. The products should be
stored in closed vessels in dry store rooms set apart for the purpose.

Modern cyanide of potassium factories which work up molasses, from which
the sugar has been removed, and also residuary distillery liquors, so
far conform with hygienic requirements that all the apparatus is under
negative pressure, so that poisonous gases cannot escape into the
workrooms.


Coal Tar, Tar Products

(See also pp. 96-119)

Care must be taken for the removal of injurious gases developed in the
manipulation and use of tar (tar distillation) and in the processes
of cleaning connected therewith. This can be most effectively done by
carrying on the processes in closed apparatus. Hofmann describes such
a factory where all mixing vessels in which the distillation products
are further treated are completely closed in, so that even in mixing and
running off, no contact is possible with the material.

The vessels for holding tar, tar-water, &c., must be impervious and
kept covered. Only the cold pitch and asphalt should be stored in open
pits. The cooling of the distillation products and residues, so long as
they give off poisonous and strongly-smelling fumes, should be carried
out in metal or bricked receivers. Such directions find a place in the
‘Technical Instructions’ appended to the German Factory Code. Without
doubt, tar is, because of its smell and for other reasons, unpleasant to
handle, and the danger to health from contact with it is not a matter
of indifference. Spilling of small quantities of tar during transport
and other manipulations can hardly be avoided. Careful cleanliness,
therefore, on the part of workers is strongly urged. It may be mentioned
that if tar is covered with a layer of tar-water, treatment with acid
fluids develops sulphur and cyanogen compounds, which may affect the
workers. Tar water should, therefore, be separated carefully from the tar
and used for the preparation of ammonia.

The same remarks as to cleanliness, &c., apply in the manufacture of
felt, lamp-black, and briquettes, with use of tar. Saturation of felt,
and manufacture of tar plaster should be done in closed apparatus.
In the production of lamp-black, even with a great number of soot
chambers, there is escape of soot causing nuisance to workers and the
neighbourhood. Complete avoidance of this seems to be difficult, so that
measures for personal hygiene must be assured. In briquette factories it
has been found useful to heat the tar by means of steam instead of by
direct fire, which renders possible the use of a closed apparatus and
mechanical stirring.

In the distillation of tar, during the first distillation period (first
runnings) unpleasant and injurious gases containing ammonia and sulphur
escape from the stills. These should (according to Leymann) be carried
away through closed pipes branching off from the lower end of the
running-off pipe, either into the furnace (in doing which a possible back
flash of flame is to be guarded against) or be subjected to purification
by lime or oxide of iron (similar to that in the case of illuminating
gas) with a view to recovery of ammonia and sulphur. The lower end of the
distillation pipes should be U-shaped so as to form a liquid seal—the
pipes for the drawing off of the gases branching off before the curve. In
the later stages of distillation risk can be checked by careful cooling
and imperviousness of the apparatus.

Very unpleasant yellow fumes develop in great quantity when pitch is run
off from the hot still. Hence hot pitch should not be run off into open
pitch receptacles, but be cooled first in closed receptacles.

The crude products obtained by distillation (light oil, creosote oil)
are subjected to purification consisting in treatment on the one hand
with alkali and on the other with acid and followed by fractional
distillation. In these processes injurious fumes may develop, therefore
they must—as already mentioned—be carried on in closed vessels provided
with means of escape for fumes and appliances for mechanical stirring;
the fumes drawn off must be led into the chimney stack.

In the distillation of brown coal, of tar, and of resin, it is necessary,
as in the distillation of coal tar, to insist above all on careful
cooling and condensation, and thorough absorption of uncondensed gases
in washing towers. Special precautionary rules are necessary to guard
against the danger of entering tar stills for cleaning purposes. Such
directions were approved in Great Britain in 1904 in view of accidents
which occurred in this way:

    TAR DISTILLING

    The following directions[I] are approved by the Home Office
    and are applicable to factories in which is carried on the
    distillation of tar for the production of naphtha, light oil,
    creosote oil, and pitch.

    1. During the process of cleaning, every tar still should
    be completely isolated from adjoining tar stills either by
    disconnecting the pipe leading from the swan neck to the
    condenser worm, or by disconnecting the waste gas pipe fixed
    to the worm end or receiver. Blank flanges should be inserted
    between the disconnections. In addition, the pit discharge pipe
    or cock at the bottom of the still should be disconnected.

    2. Every tar still should be ventilated and allowed to cool
    before persons are allowed to enter.

    3. Every tar still should be inspected by the foreman or other
    responsible person before any workman is allowed to enter.

    4. The inspecting foreman on first entering any tar still
    or tank, and all persons employed in tar stills or tanks in
    which there are no cross stays or obstructions likely to cause
    entanglement, should be provided with a belt securely fastened
    round the body with a rope attached, the free end being left
    with two men outside whose sole duty should be to watch and
    draw out any person appearing to be affected by gas. The belt
    and rope should be adjusted and worn in such a manner that the
    wearer can be drawn up head foremost and through the manhole
    and not across it.

    5. A bottle of compressed oxygen, with mouthpiece, should be
    kept at all times ready for use; and printed instructions as
    to the use of this bottle, and the method to be employed for
    resuscitation by means of artificial respiration should be kept
    constantly affixed. A draft of such instructions is appended.

    6. A supply of suitable chemical respirators properly charged
    and in good condition should be kept ready for use in case
    of emergency arising from sulphuretted hydrogen or certain
    poisonous gases. (Granules of carbon saturated with a solution
    of caustic soda readily absorb sulphuretted hydrogen and may be
    used for charging respirators.)

    7. The use of naked lights should be strictly prohibited in
    any portion of the works where gas of an inflammable nature is
    liable to be given off.

    8. Each still should be provided with a proper safety valve,
    which should at all times be kept in efficient working
    condition.


GASSING

    _Symptoms._—The first symptoms are giddiness, weakness in the
    legs, and palpitation of the heart. If a man feels these he
    should at once move into fresh warm air, when he will quickly
    recover if slightly affected. He should avoid exposure to cold.
    He should not walk home too soon after recovery; any exertion
    is harmful.

    _First Aid._—Remove the patient into fresh warm air. Send for
    the oxygen apparatus. Send for a doctor. Begin artificial
    breathing at once if the patient is insensible and continue it
    for at least half-an-hour, or until natural breathing returns.
    Give oxygen[J] at the same time and continue it after natural
    breathing returns.

    _Artificial Breathing_ (_Schäfer Method_).—Place the patient
    face downwards as shown in the diagrams.

    Kneel at the side of the patient and place your hands flat in
    the small of his back with thumbs nearly touching, and the
    fingers spread out on each side of the body over the lowest
    ribs (_see_ Diagram 1).

    [Illustration: DIAGRAM 1]

    Then promote artificial breathing by leaning forward over the
    patient and, without violence, produce a firm, steady, downward
    pressure (_see_ Diagram 2). Next release all pressure by
    swinging your body backwards without lifting your hands from
    the patient (_see_ Diagram 1).

    [Illustration: DIAGRAM 2]

    Repeat this pressure and relaxation of pressure without any
    marked pause between the movements, _about 15 times a minute_,
    until breathing is established.

In my opinion as expressed in the general discussion, use of breathing
apparatus (smoke helmets) with oxygen is strongly advisable; these
implements must be put on before entering the still.

In creosoting wood, opening the apparatus and taking out the steeped
wood should only be done when the apparatus is sufficiently cooled, as
otherwise injurious fumes escape.

In heating asphalt unpleasant fumes arise which should be drawn off into
a furnace, or absorbed by a condenser charged with oil (Leymann); open
pans should be avoided, as injurious to workers.


Organic Dye-stuffs, Coal-Tar Colours.

(See also pp. 107-19 and 204-15)

The hygienic measures to be adopted for the prevention of industrial
poisoning in coal-tar colour factories are chiefly concerned with the
poisonous nature on the one hand of the raw material (benzene, toluene,
&c.) and on the other of the intermediate products (nitrobenzene,
aniline, toluidine, &c.) and the subsidiary substances (chlorine, acids,
especially nitric acid, &c.,) used.

The most important measures are as follows:

In purifying the raw materials (benzene, &c.) the distillation requires
to be done under effective cooling and in impervious apparatus. If
injurious solvents are employed (such as pyridine in the production of
anthracene) the manipulations should be performed in closed apparatus
if possible, under negative pressure. The fumes exhausted should be
carefully condensed by cooling or absorbed by a spray of water or oil.

In view of the poisonous nature of benzene, the apparatus, stills,
receivers, tanks, tank waggons, &c., should only be entered for the
purpose of cleaning or repairing after preliminary thorough removal of
all residue of benzene, complete isolation from all similar apparatus
near, and thorough ventilation. Workers entering the stills, &c.,
should always be equipped with breathing apparatus (smoke helmets) and
with a supply of oxygen. Other aids, such as safety belts which are held
by helpers, are not here advocated in view of the often sudden fatal
poisoning, especially as the rescuer is easily induced to spring to the
assistance of his unfortunate mate without the necessary equipment. The
frequency of such accidents calls urgently for the use of breathing
apparatus.

In the manufacture of _diazo-_ and _nitroso-compounds_ and generally in
nitrating operations poisonous nitrous fumes are developed. By reduction
in an acid solution, acid fumes and singularly pungent-smelling compounds
can be given off. If reduction by means of tin is practised, the arsenic
in the tin can cause evolution of the extremely poisonous arseniuretted
hydrogen gas. In sulphonating, sulphur dioxide can develop; and
sulphuretted hydrogen gas on heating with sulphur or sulphide of sodium.

All manipulations should take place in tightly closed-in apparatus
provided with exhaust, and the gases drawn off should be absorbed or
effectively carried away. In the case of many injurious gases it is
not sufficient merely to conduct them into the flue; they ought to
be condensed and got rid of. Thus acid fumes (nitrous fumes, sulphur
dioxide, hydrochloric acid vapour, chlorine gas) are neutralised by water
or milk of lime, or a solution of soda; ammonia or alcohol by water;
sulphuretted hydrogen and arseniuretted hydrogen by lime and oxide of
iron; aniline, &c., by dilute acids.

Production of _nitrobenzene_, by nitrating benzene requires to be done in
closed apparatus, provided with mechanical agitators. In the subsequent
separation of the nitrating acids from the resulting nitro-compounds,
escape of vapourised nitro-compounds can scarcely be avoided even if
closed apparatus is used. Provision, therefore, must be made for abundant
ventilation of the workrooms. The reduction of the nitro-compounds
(nitrobenzene, nitrotoluene) to aniline (toluidine) must similarly take
place in closed agitating vessels. Introduction of the iron filings and
sulphuric or hydrochloric acids, also the subsequent saturation with
lime, and driving over of the aniline, &c., with steam, and collection
of the distillate, must take place in completely closed apparatus.
Nevertheless, escape of small quantities of aniline is very difficult to
prevent unless ample ventilation is provided.

In the production of _fuchsin_ by heating aniline hydrochloride
(toluidine, red oil) with nitrobenzene (formerly arsenic acid) in closed
vessels, furnished with mechanical stirring apparatus the aniline
remaining unconverted after the melting escapes in the form of steam
carrying aniline fumes, even with careful condensation, so that thorough
ventilation and the other general measures for the protection of workers
set forth on pp. 242 _et seq._ are required.

Marked injury to health and distress to workers through acid fumes are
sometimes caused by the denitration of the waste mixture of sulphuric
and nitric acids in the nitrating process, that is, by the separation of
nitric acid from the acid mixture. This denitration takes place usually
in the Glover towers of the lead chamber system which is often associated
with the manufacture of aniline. The mixed nitro-compounds of the waste
acids, however, are often not completely condensed, but pass through the
chambers and Gay-Lussac towers and escape into the air, whence arises
the constant smell of nitrobenzene in aniline factories (Leymann). In
the production of _naphthylamine_ and recovery of chlorinated products,
escaping chlorine should be led into chloride of lime chambers,
hydrochloric acid fumes into towers to be absorbed by water and milk of
lime or a solution of soda.

In aniline factories danger can scarcely be wholly avoided, as the
workers, on the one hand, come into contact with poisonous substances,
nitrobenzene, aniline, &c., and on the other hand, in spite of all
technical hygienic measures, can hardly help breathing in some of the
aniline. Apart from the technical regulations, therefore, there must
be insistence on cleanliness of the workrooms, personal cleanliness on
the part of the workers (washing, baths, working suits, cloak-rooms,
&c.). Besides this, contact with aniline, nitrobenzene, &c., wetting of
the body and clothes with these substances, and, especially spilling,
splashing, and scattering these fluids must be carefully avoided.
The workers require to be suitably instructed as to the symptoms of
nitrobenzene and aniline poisoning, and the right steps to take, if
poisoned. The oxygen apparatus must always be at hand, ready for use; the
workers must be instructed how to use it. Further, workers, especially
those newly employed, must be under supervision in order that assistance
may be rendered them on the first signs of poisoning; medical assistance
ought to be within easy reach. Workers also should know of the tendency
of aniline to cause cancer of the bladder.

Precautions against the poisonous nitro-derivatives of benzene
(nitrophenol, picric acid, &c.), which are in the form of poisonous dust,
must take the form of entirely closed-in grinding and packing apparatus,
or, at all events, removal of the dust at its source.

Among official regulations may be mentioned the Prussian Ministerial
Edict, dated December 18, 1908, as to purification and storage of
benzene, and further the Regulations dated December 13, 1907, and
December 30, 1908, in force in Great Britain for the manufacture
of nitro- and amido-derivatives of benzene, and the manufacture of
explosives with use of dinitrobenzene or dinitrotoluene.




VI

_PREVENTIVE REGULATIONS—THE EXTRACTION OF METALS (SMELTING WORK IN
GENERAL)_


Danger is incurred when the furnace leaks, a condition which generally
occurs in the course of time, or if gases escape during the necessary
manipulations through the working doors. This can be avoided by
maintaining the walls in as air-tight a state as possible; but as very
small leakages are almost unavoidable the best course is to so regulate
the draught in the furnace (by means of fans) that a slight negative
pressure always exists in it. Naturally, poisonous gases escaping from
the furnace such as sulphur dioxide, carbonic oxide, carbon dioxide,
and hydrocarbons require to be drawn away and rendered harmless. This
can often be done by merely conducting them into the main flue. Gases
containing carbonic oxide possess high heating capacity, and their
escape can usually be prevented by suitable cupola bells. They can be
led away in impervious conduits and utilised for heating purposes or
for driving gas engines. Entering the flues for cleaning or repairing
purposes is especially dangerous; and as it is difficult to isolate one
portion entirely from another, such operations might well be carried on
by persons equipped with breathing apparatus (smoke helmets or oxygen
apparatus).

In roasting operations handwork can be largely replaced by furnaces
worked mechanically. If the gases generated are rich in sulphur dioxide
they can be utilised for the manufacture of sulphuric acid or for
the production of liquid sulphur dioxide either directly or after
concentration; if not, they must be rendered harmless by treatment with
milk of lime in absorption towers. Other methods of rendering the sulphur
dioxide (unsuited for manufacture of sulphuric acid) harmless depend on
treatment with minerals containing calcium carbonate, or magnesium or
aluminium hydrate, sodium sulphide, &c. Sometimes the sulphurous gases
are led into blast furnaces containing oxide of iron and coal (so as to
form sulphide of iron) or are absorbed by means of moist scraps of sheet
iron or brown coal or peat briquettes.

Use of chlorine compounds in the extraction of metals from ores (silver,
copper) causes evolution of chlorine and hydrochloric acid vapour. These
should be dealt with in absorption towers. Metallic fumes are collected
by suitable condensing arrangements. Flue dust is retained in flue dust
chambers, but in the cleaning of such condensing flues and chambers
danger to the workers is considerable and they should be equipped with
respirators, working suits, &c. Personal hygiene must be insisted on.


Iron

(See also pp. 146-51)

In blast furnace work, industrial poisoning occurs mainly from escaping
gases rich in carbonic oxide. They may also contain sulphur dioxide and
cyanogen compounds. The high proportion of carbonic oxide, however, makes
these gases valuable and serviceable, because of their great heating
value. They are, therefore, now led away and utilised, the furnace being
closed by a cupola bell only opened by means of a mechanical contrivance
when charging is necessary; while this is being done the ignited blast
furnace gases pour out, and the workers retire from the opening, so
that danger to them is avoided. The construction of a blast furnace
with a cupola bell can be seen in fig. 29. The blast furnace gases are
conducted away by an opening in the side, and pass along special pipes
to be utilised, after having gone through a purifying process mainly for
the removal of flue dust, &c. The gases serve partly for the heating of
the blast for the furnace itself, and partly for driving the gas engines
which serve the electrical power apparatus, electric lighting, &c., in
the works. Through the rational utilisation of the blast furnace gases,
the workers are protected from their injurious action during the working
of the furnace. Serious gas poisoning, however, occurs not infrequently
to workers who have to enter the gas mains for cleaning purposes.
Workers, therefore, should only be permitted to enter the flues, &c.,
a considerable time after the process has been stopped and after as
complete and thorough a ventilation of the system as is possible.

Any portion of the gas system which is to undergo cleaning must be
completely isolated. Ventilation is best effected by the introduction of
compressed air. Thus a foundry (in the Duisburg district) has provided
all its cellars and passages, through which gas pipes pass, and which
must be entered during repairs, with compressed air pipes. It is,
however, advisable that gas conduits should only be entered by workers
equipped with breathing apparatus and oxygen supply. Naturally adequate
instruction of workers and training in first aid are necessary, as well
as a sufficient supply of oxygen in constant readiness.

Injurious gases can escape from the furnace during tapping and slag
running; poisonous gases with a disagreeable odour, from presence of
sulphuretted hydrogen, also arise in granulating the slag, that is, when
the fluid slag is led into water for subsequent use in preparation of
cement. These gases should be collected by hoods, and be carried away as
far as possible.

In the manufacture of _steel_ by the _Bessemer_ or _Thomas-Gilchrist_
process, the dark smoke arising out of the converter during the blowing
operation should be drawn off (led into flues), as it is injurious to
health. In the _Martin_ furnaces poisoning may occur, especially when
the gas flues are entered after cessation of work. In letting out the
gas in order to stop the furnaces, the gas and air valves must first be
closed and the outlet valves for gas be opened only after the pipes have
been filled with steam. Steam is to be driven through until the pipes
are quite free from gas, and the system only entered after it has become
thoroughly cooled. If need arises for entering portions of the system
while neighbouring parts are still filled with gas, the workers employed
require to be provided with breathing apparatus and smoke helmets.

In the transport of _ferro-silicon_ several cases of poisoning have
occurred. Cautionary regulations, therefore, relating to this work have
been found necessary.

Such directions are contained in the police regulations of the Prussian
Minister of Trade and Industry respecting the transport on the Rhine of
corrosive and poisonous substances (dated September 29, 1910).

It is prescribed: (1) that ferro-silicon be packed in strong watertight
cases of wood or metal; (2) that on the cases be inscribed, legibly and
indelibly, the notice ‘Ferro-silicon. To be kept dry! With care!’ (3)
that the substance be delivered dry and in dry cases; (4) that the cases
be stored in airy places on the deck of the ship in such a manner that
they are protected from wet.

Further, care is to be taken that the storage on ships is done in such a
way that possible damage to the material in which it is packed entails no
risk. The harbour authorities where loading or landing takes place can
deal with special cases as they think fit.

International regulation as to transport of ferro-silicon in the spirit
of the above regulations would be most desirable in view of the oversea
trade in this substance.[K]


Lead

(See also pp. 120-40 and 177-82)

For protection against lead poisoning, the most widely spread of the slow
industrial poisonings, all those measures are of moment which we have
described in our general discussion on protection against danger from
poison in industries, both personal and general.

Personal hygiene, especially careful washing after work, prohibition of
eating in workrooms, suitable working clothes, provision of cloak rooms,
meal rooms, baths, &c., are important and effective measures for the
protection of workers against industrial lead poisoning.

The worker should naturally be adequately instructed as to the risk.
Appropriate printed notices are especially adapted for this purpose.

Further, selection of workers should be made under medical supervision.
Workers who suffer from specific disease which, if associated with lead
poisoning, may prove dangerous, should be excluded from all contact
with lead. Among such illnesses must be reckoned tuberculosis in all
its forms, alcoholism, epilepsy, tendency to mental disease (nervous
disposition, hysteria, neurasthenia, &c.), rheumatism, and disease of the
kidneys.

Overtime work undoubtedly increases risk; therefore working hours should
be shortened as much as possible, and handwork replaced by machine work
where possible. Young persons and women especially should be excluded
from work in lead. Alternation of employment also is beneficial and
essential in very dangerous lead work, because the poison accumulates in
the body and only during intervals wherein absolutely no poison can be
absorbed has it time to be eliminated.

Periodical medical examination by a surgeon is of great value with
systematic entry of the results of examination in a health register. As
bearing on this, early diagnosis is of the greatest importance, so that
workers in whom the first signs of lead poisoning appear may at once be
suspended or transferred to other work.

Lead workers should take suitable nourishing food and avoid particularly
alcoholic excess.

When the danger is due to fumes or dust in the air the measures
prescribed on pages 242-55 apply, particularly those which aim at keeping
the workrooms and the air in the factories free of them by locally
applied exhaust ventilation.

In order to replace or reduce the use of lead we strongly advocate the
use of non-poisonous, or at any rate less poisonous, substances, where
this can be done without technical difficulties, as, for instance,
carborundum discs instead of lead in polishing of precious stones,
leadless glaze in pottery for lead glaze (so far as this is possible,
as to which see page 319), beds free of lead (in different industries)
for lead beds. In a number of cases, however, such substitution is
impracticable on technical grounds or can only partially be carried out,
as, for example, in letterpress printing and in the paint and colour
industry, in which the prohibition of lead has often been repeatedly
urged. So far, unfortunately, it must be admitted that repeated attempts
to find a non-poisonous substitute for lead colours, especially for
white lead, of equal value technically, have not succeeded. Endeavours
have been made to substitute for lead, zinc preparations (zinc white,
lithopone, &c.), but hitherto (in regard to durability, opacity, &c.)
with incomplete success.

Mention must be made of the measures based upon the relatively
non-poisonous nature of lead sulphide. Lead sulphide is, in spite of
various assertions to the contrary, practically non-poisonous; a fact
attributable to its insolubility in water and weak acids. As lead
sulphide is the only non-poisonous lead compound it is a duty to take
advantage of this fact for purposes of lead prophylaxis.

Attempts with this end in view were made by the introduction of sulphur
soaps in lead factories. Soaps containing in large quantity soluble
alkaline sulphides convert lead compounds adhering to the skin into
black lead sulphide. The lead compounds are in this way made harmless,
and besides this the worker is impelled to remove the staining by
washing. Such a sulphur soap has been brought into the market under the
name of akremnin soap, but does not enjoy special popularity with the
workmen on account of its unpleasant smell.

The struggle against the risks of lead employment has been going on ever
since efforts for the protection of workers were commenced.

The International Association for Labour Legislation has made valuable
inquiries in this direction. The question of lead poisoning had been
repeatedly discussed by this Association and its branches in various
countries. The International Labour Bureau also took up the issue and
in 1906—supported by the Institute for General Welfare in Frankfurt
a-M.—offered a prize for the best treatise on the prevention of
industrial lead poisoning. The outcome of this competition was the volume
compiled by Leymann, ‘Die Bekämpfung der Bleigefahr in der Industrie’
(published by Fischer, Jena, 1908).

In connection with the resolution adopted at the third Congress of the
International Association for Labour Legislation the Union of Social
Reform (as the German branch is called) addressed the Federal Council on
the white lead question, the chief points insisted upon being the need
for: (1) regulations for the house painting industry in pursuance of
Section 120 of the Factory Code; (2) report by the Imperial Health Office
on the practicability of substitutes for lead; (3) exclusion of lead
colours from use in the painting of public buildings; and (4) treatment
of lead poisoning by the State Insurance Office as an accident entitling
to compensation.

These demands were supported by the central office of the Society for
Promoting the Welfare of Workers, which had as far back as its seventh
conference in 1898 occupied itself with the question of dangerous trades
and especially, at its conference in 1905, taken up the subject of the
protection of workers against industrial poisoning.

In Germany these efforts resulted in the passage of a number of Imperial
Regulations for separate lead industries.

In other countries similar action was set on foot. In Austria, where the
subject is of special importance in view of the part played by lead in
the home industries, the Government undertook to improve the conditions
in industries attended with risk of lead poisoning. For this purpose
the Statistical Office of the Ministry of Commerce and Labour has,
since 1904, carried out extensive inquiries into lead and zinc smelting
works, paint and colour factories, the painting and varnishing trades,
letterpress printing, and the ceramic industry. The results are contained
in the volume ‘Lead Poisoning in Smelting Works and Industries Generally’
(published by Hölder, Vienna).

As in Germany and Austria, so also in Great Britain, France, Switzerland,
Belgium, and the Netherlands, regulations in various lead industries were
enforced after previous official inquiry and report.

A general code, however, affecting all lead industries has only been
published in one or two states. And yet this would, in my opinion, be
of very great practical value as it is hardly possible to regulate each
single branch of industry.

In Germany the Regulations dated May 26, 1903, dealing with lead colours
are certainly comprehensive, but relate primarily to paint factories, and
are not, therefore, a general Order in the sense indicated. In Saxony the
decree of June 27, 1901, made notification of lead poisoning compulsory,
and in the subsequent decree of April 16, 1909, prescribed general
measures against lead poisoning. In Switzerland single cantons have made
general regulations. In France, by a decree dated April 23, 1908 (in
pursuance of the general law of June 12, 1893), all industries attended
with risk of lead poisoning were brought under Regulation.

We give the provisions of this interesting decree, as it is a good
example of the kind of Regulations we have in mind.

    DECREE OF THE PRESIDENT OF THE FRENCH REPUBLIC (APRIL 23, 1908)
    RELATING TO CERTAIN INDUSTRIES IN WHICH LEAD IS USED

    1. In the lead industries hereinafter mentioned, viz.:
    smelting, cupellation of argentiferous lead, manufacture
    of accumulators, glass-making, manufacture and use of lead
    enamels, manufacture of pottery, decoration of porcelain
    or faience, ceramic chromo-lithography, manufacture of
    lead alloys, oxides, salts and colours—employers, directors
    or managers are required, apart from the general measures
    prescribed by the Decree of 29 November, 1904, to take special
    measures for protection and health as set forth in the
    following sections.

    2. Lead melting pots shall be erected in an airy place
    separated from the other workrooms.

    Hoods or other means for the effectual removal of fumes shall
    be provided:—

      (_a_) Over the openings for the run of lead and slag in lead
      smelting.

      (_b_) Before the furnace doors in the manufacture of lead
      oxides.

      (_c_) Above the pots for melting lead or its alloys, in the
      other industries enumerated in Section 1.

    3. All work with oxides and other compounds of lead capable of
    producing dust shall be done as far as possible when in a damp
    condition.

    When this work cannot be done in the presence of water or other
    liquid, it shall be carried out by mechanical means, in covered
    air-tight apparatus.

    If it is impossible to conform to the requirements of either
    of the first two paragraphs of this section, the work shall
    be done under a strong draught so arranged that the harmful
    products may be intercepted by apparatus suitably placed.

    Finally, if none of these systems is possible the workmen shall
    be supplied with respirators.

    4. Oxides and other compounds of lead, whether dry or damp,
    in suspension or solution, shall not be handled with the bare
    hand. The employer shall at his own expense provide the workers
    in these operations with either gloves made of impervious
    material such as indiarubber, or suitable appliances, and shall
    cause them to be kept in good repair and frequently cleaned.

    5. Tables on which these products are handled shall be covered
    with some impervious material, kept in a perfectly water-tight
    condition.

    The same requirement applies to the floors of the workrooms,
    which shall also be kept damp.

    The floor shall be slightly sloped towards a water-tight
    receptacle for collecting the lead substances which are washed
    down.

    The work shall be so arranged that there shall be no
    splashing. The tables, floors and walls shall be washed at
    least once a week.

    6. Without prejudice to the requirements of section 3, the
    grinding and mixing of lead products, and the use of them
    in dusting shall be effected in special places with active
    ventilation.

    If the materials cannot be damped, the workers shall be
    provided with respirators.

    7. Pottery shall not be dipped with bare hands in solutions
    containing litharge, red lead, galena or white lead in
    suspension.

    8. No food or drink shall be brought into the works.

    9. Employers shall, at their own expense, provide and maintain
    for the use of the workers, overalls or clothing for use during
    work only, in addition to gloves and respirators.

    10. In a part of the building separated from the workrooms,
    there shall be provided for the use of the workers exposed to
    lead dust or fumes, a cloak room and lavatory kept in good
    order, provided with basins or taps in sufficient number, a
    plentiful supply of water, soap and a towel for each worker
    replaced at least once a week.

    The cloak rooms shall be provided with cupboards or drawers
    with locks or padlocks, the ordinary clothing being kept apart
    from the working clothes.

    11. A warm bath or shower bath shall be provided each week for
    the workers exposed to lead dust or fumes.

    A warm bath or shower bath shall be provided every day after
    work, for each worker employed, either in emptying or cleaning
    the condensing chambers and flues, in repairing furnaces in
    lead works, in carrying lead corrosions from the beds in white
    lead factories, in packing red lead, in grinding lead enamels
    and in dry dusting.

    12. Employers are required to exhibit, in a conspicuous
    position in the works, regulations imposing on the workers the
    following obligations:—

      To use the appliances, gloves, respirators, and working clothes
      placed at their disposal.

      Not to bring into the works either food or drink.

      To pay great care, before each meal, to the cleanliness of the
      mouth, nose, and hands.

      To take the baths weekly or daily as provided in section 11.

    13. The Minister of Labour may, by Order made with the advice
    of the Consultative Committee for Arts and Manufactures, exempt
    an establishment for a specified period, from all or part of
    the requirements of Regs. 2ᵃ, 2ᵇ, 2ᶜ, 5² and 6¹ in any case
    where it is found that observance of these requirements is
    practically impossible, and that the health and safety of the
    workers are assured by conditions at least equivalent to those
    prescribed in the present Order.

    14. Subject to additional postponements which may be granted
    by the Minister in pursuance of Section 6 of the Act of 12th
    June, 1893 (as amended by that of 11th July, 1903), the delay
    required for the carrying out of the alterations necessitated
    by the present Decree is limited to one year from the date of
    its publication.

    15. The Ministry of Labour is charged with the administration
    of this Decree.

This decree was supplemented by further noteworthy additions requiring
medical supervision in lead industries as follows:

    DECREE OF DECEMBER 28, 1909, ORGANISING MEDICAL SERVICE IN
    INDUSTRIES EXPOSING THE WORKERS TO RISK OF LEAD POISONING

    1. In premises in which the processes enumerated in Regulation
    1 of the Decree of April 23, 1908, are carried on medical
    attendance as prescribed below shall be provided.

    2. A surgeon appointed by the occupier shall examine the
    workers and enter the results of examination required in
    Regulations 3 and 4. The examinations shall be paid for by the
    occupier.

    3. No person shall be employed in work mentioned in Regulation
    1 of the Decree of April 23, 1908, without a certificate from
    the surgeon stating that he is free from symptoms of lead
    poisoning and of illness which might render him specially
    susceptible.

    4. No worker shall remain at the same employment unless
    the certificate is renewed one month after commencement of
    employment and subsequently at quarterly intervals.

    In addition to the periodical examination the occupier shall
    give an order on the surgeon to every workman declaring himself
    to be ill from his employment or who desires to undergo medical
    examination.

    5. A special Register open to the Factory Inspector shall be
    kept containing the following particulars of each worker:

    (1) Dates and duration of absence on account of illness of any
    kind;

    (2) Dates of medical certificates for such illness, the notes
    made by the surgeon and the name of the surgeon furnishing them;

    (3) Instructions given by the appointed surgeon in pursuance of
    Regulations 3 and 4 above.


Lead Smelting Works

(See also pp. 122-31)

As the fumes in lead smelting works contain a high proportion of lead,
all apparatus, especially furnaces and working doors, should be provided
with efficient exhaust ventilation and all flues, furnaces, and other
apparatus be as airtight as possible. Where lead dust is created exhaust
ventilation locally applied is necessary. Two of the most important
preventive measures are personal cleanliness and alternation of
employment. Dust arising in the furnaces and borne along by the furnace
gases together with arsenical fumes and dust must be deposited in flues
or chambers.

In view of the importance of proper instruction of smelters as regards
the danger we quote the warning note prepared by the Institute for
Industrial Hygiene, Frankfurt a.-M., which deserves wide circulation.

    LEAD LEAFLET FOR SMELTERS

    _How does Lead Poisoning arise?_

    The danger of lead poisoning in lead, spelter and other
    smelting premises can be avoided if due care is observed.

    Lead poisoning occurs when lead enters the system. This takes
    place by breathing dust and fume containing lead, or by eating
    and drinking, smoking, snuff taking and tobacco chewing if food
    or tobacco is taken into the mouth with dirty hands and dirty
    face and beard.

    No one is immune from lead. Lead accumulates in the body of
    careless persons and he who is not sick to-day can be so
    to-morrow or after weeks or months.

    _How can Plumbism be avoided?_

    All smelters must observe cleanliness. In this respect they
    should see to the following points:

    1. It is to their interest to see that the exhaust ventilation
    is kept in order and that the Special Rules or Regulations are
    exactly followed. Further, special clothing should be worn, the
    mouth and nose should be covered, and the floors sprinkled.

    2. It is especially important that in intervals and at the
    close of work the mouth, face, beard, and hands should be
    carefully cleaned. Food should not be eaten or the premises
    left without putting on fresh clothes and thoroughly washing
    or, still better, bathing. When drinking, the edge of the
    drinking glass should not be fingered with dirty hands.
    Especially important is it that the teeth should be cleaned and
    the mouth washed out.

    3. During work smoking, snuff taking, and tobacco chewing,
    which invariably convey lead into the mouth, should be
    given up, as it is impossible to prevent the hands getting
    contaminated with lead. Lighting the pipe with glowing lead
    ashes is in the highest degree dangerous from the risk of
    inhaling lead fume. The body must be strengthened to withstand
    the action of lead. Moderation in drinking, especially
    avoidance of spirits, should be observed. Alcoholic subjects
    succumb to lead poisoning much more readily than the temperate.

    Food should be abundant and rich in fat, for example milk and
    bacon. Thick soups are excellent before work. Work should never
    be begun on an empty stomach. And lastly as much fresh air as
    possible. Walking, athletics, work in the garden and field will
    help to keep off many an attack. If anyone thinks that he is
    suffering from lead poisoning he should at once in his own and
    his family’s interest see the doctor of his sick club.

The following are the

    GERMAN IMPERIAL REGULATIONS FOR LEAD SMELTING WORKS, DATED JUNE
    16, 1905

    _General Regulations_

    1. Workrooms in which lead ores are roasted, sintered, or
    smelted, pig lead produced and submitted to further treatment,
    distillation of rich lead (bullion cupellation) litharge, red
    lead, or other oxides of lead prepared, ground or sieved,
    stored or packed, or zinc skimmings distilled, shall be roomy,
    high, and so arranged that a sufficient constant exchange of
    air takes place. They shall be provided with a level and solid
    floor to allow of easy removal of dust by a moist method.

    The walls shall be smooth so as to prevent collection of dust;
    they shall be either washed down or lime washed at least once a
    year.

    Provided that this shall not apply in the case of calcining
    sheds with wooden walls.

    2. An abundant supply of good drinking water, protected against
    contamination from dust, shall be provided for the workers on
    the furnaces and smelting pots, and in such close proximity to
    them, that they can obtain it at any time without having to go
    into the open air.

    Arrangements for sprinkling the floors shall be provided near
    the furnaces. The floors of the rooms mentioned in paragraph 1
    shall be wet cleansed at least once daily.

    3. Prepared (i.e. concentrated) lead ores and leady smelting
    products, unless moist, shall not be crushed except in an
    apparatus so arranged as to prevent as far as possible
    penetration of dust into the workrooms.

    Provided that this shall not apply to calcined material from
    converters.

    Sacks in which lead ores and materials containing lead have
    been packed shall not be freed from dust and cleaned except in
    a dust-proof apparatus or by washing.

    4. Materials containing lead for charging the blast-furnaces,
    if they are oxides and form dust, shall be damped before they
    are mixed with other materials, stocked on the feeding floor,
    or charged into the blast-furnaces.

    Provided that this shall not apply in the case of calcined
    material from converters.

    5. Dust, gases, and lead fumes, escaping from furnaces, and
    converters, tapping spouts, tapping pots, drain sump, slag
    pots, slag cars, or slag channels, and from glowing residues
    taken from the furnaces, shall be caught as near as possible to
    the point of origin and removed harmlessly.

    Dust collecting chambers, flues, as well as furnaces which
    have been ‘blown down,’ shall not be entered by workmen unless
    sufficiently cooled and ventilated.

    _Special Regulations for such parts of a factory where lead
    colours are prepared_

    6. In grinding, sieving and packing dry leady materials, in
    charging, and emptying litharge and red lead furnaces, in
    collecting the red lead and similar operations in which leady
    dust is developed, exhaust arrangements shall be provided for
    preventing the entrance of dust into the workrooms.

    7. Apparatus producing leady dust, if their construction and
    manner of use does not effectually prevent evolution of dust,
    shall have all cracks protected by thick layers of felt or
    woollen material, or by similar means, so as to prevent the
    entrance of dust into the workrooms.

    Apparatus of this character shall be provided with arrangements
    for preventing compression of air in them. They shall only be
    opened when the dust in them shall have completely settled, and
    they are absolutely cool.

    _Special arrangements in force for the distillation of zinc
    skimmings_

    8. Proposed new furnaces for the distillation of zinc skimmings
    (for which according to pars. 16 and 25 of the Industrial Code
    a special permission is required) shall be so arranged that (1)
    there shall be at least a clear space of 10 feet in front of
    the charging opening; (2) any passages under the distillation
    rooms shall be roomy, at least 11½ feet high in the centre,
    light and airy.

    9. Dust, gases, and fumes arising from the zinc skimmings
    distillation furnaces shall be collected as near as possible to
    the point of origin, and carried outside the smelting room.

    The entrance of gases from the fires into the smelting room
    shall be prevented as far as possible by suitable arrangements
    for drawing them off.

    10. Sieving and packing of by-products obtained in the
    distillation of zinc skimmings (poussière, flue dust) shall
    not be done except in a special room separated from the other
    workrooms, and complying with the requirements of Reg. 1.

    Sieving shall only be done in an apparatus so constructed that
    dust shall not escape.

    _Employment of workers._

    11. Women and young persons shall not be employed or permitted
    in rooms mentioned in Reg. 1, in flue dust chambers, or dust
    flues, or in the removal of flue dust.

    12. No person shall be newly employed in rooms mentioned
    in Reg. 1, in flue dust chambers, or dust flues, or in the
    transport of flue dust, without a certificate of fitness from
    the surgeon appointed by the higher authorities.

    These certificates shall be collected and shown to the Factory
    Inspector and Appointed Surgeon on request.

    13. No person shall be employed in charging blast furnaces,
    apart from mere labouring work on the floors, for more than
    eight hours daily. The same shall apply in the case of workmen
    employed in the inside of furnaces when cool, or in emptying
    flue dust chambers, or dust flues which contain wet flue dust.

    No person shall be employed in cleaning out, from inside, flue
    dust chambers, or dust flues containing dry flue dust for more
    than four hours daily; and including emptying and work of
    transport of this kind altogether no longer than eight hours
    daily.

    Other workers in rooms specified in Reg. 1 shall not work more
    than 10 hours in 24, exclusive of mealtimes.

    Exception to this is allowed in the case of those workers who
    are employed for the purpose of a weekly change of shift, and
    for whom exception as to Sunday employment is permitted by
    Imperial Decree.

    _Clothing, overalls, lavatory accommodation, &c._

    14. The occupier shall provide for all persons employed in
    cleaning out flue dust chambers, dust flues, repairing of
    cooled furnaces, grinding, sieving and packing of litharge, red
    lead, or other lead colours, complete suits of working clothes,
    including caps and respirators.

    15. Work with lead salts in solution shall not be done except
    by workers who either grease their hands or are provided with
    impermeable gloves.

    16. The suit of clothes, or overalls, provided in Regs. 14 and
    15, respirators and gloves, shall be provided in sufficient
    amount and in proper condition. The occupier shall see that
    they are always suitable for their purpose, and are not worn
    except by those workers for whom they are intended; and that
    they, at stated intervals (the overalls at least once a week,
    the respirators and gloves prior to use), are cleaned, and
    during the time that they are not in use are kept in a place
    specially reserved for each article.

    17. A lavatory and cloak room shall be provided for the use of
    the workmen in a part of the building free from dust. Separate
    from it there shall be a dining-room. These rooms must be kept
    free from dust and be warmed during the winter.

    In a suitable place provision shall be made for warming the
    workers’ food.

    Water, soap, and towels, and arrangements for keeping separate
    the overalls from other clothing taken off before the
    commencement of work shall be provided in sufficient amount in
    the lavatory and cloak room.

    The occupier shall afford opportunity for persons engaged in
    cleaning out flue dust chambers, dust flues, and the cooled
    furnaces, to take a bath daily after the end of the work, and
    for those handling oxides of lead, at least once a week, during
    working hours inside the works. The bathroom shall be warmed
    during the winter.

    18. The occupier shall place the supervision of the health of
    the workers in the hands of a surgeon, appointed by the higher
    authorities for this purpose, whose name shall be sent to the
    Inspector of Factories. The surgeon shall examine the workers
    at least once a month in the factory, with a view to the
    detection of symptoms of lead poisoning.

    The occupier shall not employ persons suspected by the surgeon
    of having contracted lead poisoning in the processes mentioned
    in Reg. 1 or in cleaning out flue dust chambers, dust flues, or
    furnaces when cold, or transport of the flue dust, until they
    are quite well. Those who appear peculiarly susceptible shall
    be permanently suspended from working in these processes.

    19. The Health Register shall be shown to the Factory Inspector
    and Appointed Surgeon on demand. (Similar to Reg. 15 of Spelter
    Regulations.)

    20. The occupier shall require the workers to subscribe to the
    following conditions:—

      (1) Food must not be taken into the workrooms. Meals may only
      be taken outside the workrooms.

      (2) Workmen must only enter the meal room to take their meals
      or leave the factory, after they have taken off their overalls
      and carefully washed their face and hands.

      (3) Workmen must use the overalls, respirators and gloves in
      those workrooms and for the particular processes for which they
      are given them.

      (4) Cigar and cigarette smoking during work is forbidden.

      (5) A bath in the factory must be taken every day at the close
      of their work by those engaged in the emptying and cleaning of
      flue dust chambers, flues, and furnaces when cold, and by those
      employed on oxides of lead once a week.

    Provided that this shall not apply in the case of workmen
    exempted by the appointed surgeon.

    Workers contravening these orders will be liable to dismissal
    without further notice.

    21. In every workroom, as well as in the cloak room and
    meal room, there shall be posted up by the occupier, in a
    conspicuous place and in clear characters, a notice of these
    regulations.

    The occupier is responsible for seeing that the requirement
    of Reg. 20 (1) is obeyed. He shall make a manager or foreman
    responsible for the precise carrying out of Reg. 20 (1) (2) and
    (5). The person thus made responsible shall see to the carrying
    out of the regulations and for the exercise of necessary care
    as prescribed in par. 151 of the Factory Act.

    22. No work in a lead smelting works shall be commenced until
    notice of its erection has been sent to the Factory Inspector.
    After receipt of the notice he shall personally visit to
    see whether the arrangements are in accordance with these
    regulations.

    23. These regulations come into force on 1st January, 1906.
    Where structural alterations are necessary for the carrying out
    of Regs. 1, 5 (1), 6, 9, 10 and 17, the higher authorities may
    allow an extension of time to a date not later than January
    1st, 1908.

    If it seems necessary on strong grounds of public interest, the
    Council (Bundesrath) may extend the time in particular works
    until 1st January, 1913, and until then allow exceptions from
    the regulations as regards Reg. 13 (1) and (2).


Accumulator Factories

[Dr. Rambousek gives a very brief synopsis of the German Imperial
Regulations in force for this industry and mentions that in Great Britain
the Regulations of the Secretary of State dated 1903 are similar. We
have printed these, as the code is fairly representative of the English
Regulations for (1) smelting of metals; (2) paints and colours; (3)
tinning of hollow ware; (4) yarn dyed with chromate of lead; (5) vitreous
enamelling; and the special rules for (6) white lead and (7) earthenware:

    REGULATIONS DATED NOVEMBER 21, 1903, MADE BY THE SECRETARY OF
    STATE FOR THE MANUFACTURE OF ELECTRIC ACCUMULATORS

    Whereas the manufacture of electric accumulators has been
    certified in pursuance of Section 79 of the Factory and
    Workshop Act, 1901, to be dangerous;

    I hereby, in pursuance of the powers conferred on me by that
    Act, make the following regulations, and direct that they shall
    apply to all factories and workshops or parts thereof in which
    electric accumulators are manufactured.

    _Definitions._—In these Regulations ‘lead process’ means
    pasting, casting, lead burning, or any work involving contact
    with dry compounds of lead.

    Any approval given by the Chief Inspector of Factories in
    pursuance of these Regulations shall be given in writing, and
    may at any time be revoked by notice in writing signed by him.

    _Duties of Occupier_

    1. _Ventilation._—Every room in which casting, pasting or lead
    burning is carried on shall contain at least 500 cubic feet of
    air space for each person employed therein, and in computing
    this air space, no height above 14 feet shall be taken into
    account.

    These rooms and that in which the plates are formed shall be
    capable of through ventilation. They shall be provided with
    windows made to open.

    2. _Separation of processes._—Each of the following processes
    shall be carried on in such manner and under such conditions as
    to secure effectual separation from one another and from any
    other process:

      (_a_) Manipulation of dry compounds of lead;

      (_b_) Pasting;

      (_c_) Formation, and lead burning necessarily carried on
      therewith;

      (_d._) Melting down of old plates.

    Provided that manipulation of dry compounds of lead carried on
    as in Regulation 5 (b) need not be separated from pasting.

    3. _Floors._—The floors of the rooms in which manipulation
    of dry compounds of lead or pasting is carried on shall be
    of cement or similar impervious material, and shall be kept
    constantly moist while work is being done.

    The floors of these rooms shall be washed with a hose pipe
    daily.

    4. _Melting pots._—Every melting pot shall be covered with a
    hood and shaft so arranged as to remove the fumes and hot air
    from the workrooms.

    Lead ashes and old plates shall be kept in receptacles
    especially provided for the purpose.

    5. _Manipulation of dry compounds of lead._—Manipulation of
    dry compounds of lead in the mixing of the paste or other
    processes, shall not be done except (_a_) in an apparatus so
    closed, or so arranged with an exhaust draught, as to prevent
    the escape of dust into the work room: or (_b_) at a bench
    provided with (1) efficient exhaust draught and air guide so
    arranged as to draw the dust away from the worker, and (2) a
    grating on which each receptacle of the compound of lead in use
    at the time shall stand.

    6. _Covering of benches._—The benches at which pasting is done
    shall be covered with sheet lead or other impervious material,
    and shall have raised edges.

    7. _Prohibition of employment._—No woman, young person, or
    child shall be employed in the manipulation of dry compounds of
    lead or in pasting.

    8. (_a_) _Appointed Surgeon._—A duly qualified medical
    practitioner (in these Regulations referred to as the
    ‘Appointed Surgeon’) who may be the Certifying Surgeon, shall
    be appointed by the occupier, such appointment unless held by
    the Certifying Surgeon to be subject to the approval of the
    Chief Inspector of Factories.

    (_b_) _Medical examination._—Every person employed in a lead
    process shall be examined once a month by the Appointed
    Surgeon, who shall have power to suspend from employment in any
    lead process.

    (_c_) No person after such suspension shall be employed in a
    lead process without written sanction entered in the Health
    Register by the Appointed Surgeon. It shall be sufficient
    compliance with this regulation for a written certificate to
    be given by the Appointed Surgeon and attached to the Health
    Register, such certificate to be replaced by a proper entry in
    the Health Register at the Appointed Surgeon’s next visit.

    (_d_) _Health Register._—A Health Register in a form approved
    by the Chief Inspector of Factories shall be kept, and shall
    contain a list of all persons employed in lead processes. The
    Appointed Surgeon will enter in the Health Register the dates
    and results of his examinations of the persons employed and
    particulars of any directions given by him. He shall on a
    prescribed form furnish to the Chief Inspector of Factories
    on the 1st day of January in each year a list of the persons
    suspended by him during the previous year, the cause and
    duration of such suspension, and the number of examinations
    made.

    The Health Register shall be produced at any time when required
    by H.M. Inspectors of Factories or by the Certifying Surgeon or
    by the Appointed Surgeon.

    9. _Overalls._—Overalls shall be provided for all persons
    employed in manipulating dry compounds of lead or in pasting.

    The overalls shall be washed or renewed once every week.

    10. _Cloak and dining rooms._—The occupier shall provide and
    maintain:

      (_a_) a cloak room in which workers can deposit clothing put
      off during working hours. Separate and suitable arrangements
      shall be made for the storage of the overalls required in
      Regulation 9.

      (_b_) a dining room unless the factory is closed during meal
      hours.

    11. _Food, &c._—No person shall be allowed to introduce, keep,
    prepare or partake of any food, drink, or tobacco, in any room
    in which a lead process is carried on. Suitable provision shall
    be made for the deposit of food brought by the workers.

    This regulation shall not apply to any sanitary drink provided
    by the occupier and approved by the Appointed Surgeon.

    12. _Washing._—The occupier shall provide and maintain for the
    use of the persons employed in lead processes a lavatory, with
    soap, nail brushes, towels, and at least one lavatory basin for
    every five such persons. Each such basin shall be provided with
    a waste pipe, or the basins shall be placed on a trough fitted
    with a waste pipe. There shall be a constant supply of hot and
    cold water laid on to each basin.

    Or, in the place of basins the occupier shall provide and
    maintain troughs of enamel or similar smooth impervious
    material, in good repair, of a total length of two feet
    for every five persons employed, fitted with waste pipes,
    and without plugs, with a sufficient supply of warm water
    constantly available.

    The lavatory shall be kept thoroughly cleansed and shall be
    supplied with a sufficient quantity of clean towels once every
    day.

    13. Before each meal and before the end of the day’s work, at
    least ten minutes, in addition to the regular meal times, shall
    be allowed for washing to each person who has been employed in
    the manipulation of dry compounds of lead or in pasting.

    Provided that if the lavatory accommodation specially reserved
    for such persons exceeds that required by Regulation 12, the
    time allowance may be proportionately reduced, and that if
    there be one basin or two feet of trough for each such person
    this Regulation shall not apply.

    14. _Baths._—Sufficient bath accommodation shall be provided
    for all persons engaged in the manipulation of dry compounds
    of lead or in pasting, with hot and cold water laid on, and a
    sufficient supply of soap and towels.

    This rule shall not apply if in consideration of the special
    circumstances of any particular case, the Chief Inspector
    of Factories approves the use of local public baths when
    conveniently near, under the conditions (if any) named in such
    approval.

    15. _Cleaning._—The floors and benches of each workroom shall
    be thoroughly cleansed daily, at a time when no other work is
    being carried on in the room.

    _Duties of Persons Employed_

    16. _Medical examination._—All persons employed in lead
    processes shall present themselves at the appointed times for
    examination by the Appointed Surgeon as provided in Regulation
    8.

    No person after suspension shall work in a lead process, in
    any factory or workshop in which electric accumulators are
    manufactured, without written sanction entered in the Health
    Register by the Appointed Surgeon.

    17. _Overalls._—Every person employed in the manipulation of
    dry compounds of lead or in pasting shall wear the overalls
    provided under Regulation 9. The overalls, when not being worn,
    and clothing put off during working hours, shall be deposited
    in the places provided under Regulation 10.

    18. _Food, &c._—No person shall introduce, keep, prepare, or
    partake of any food, drink (other than any sanitary drink
    provided by the occupier and approved by the Appointed
    Surgeon), or tobacco in any room in which a lead process is
    carried on.

    19. _Washing._—No person employed in a lead process shall
    leave the premises or partake of meals without previously and
    carefully cleaning and washing the hands.

    20. _Baths._—Every person employed in the manipulation of dry
    compounds of lead or in pasting shall take a bath at least once
    a week.

    21. _Interference with safety appliances._—No person shall in
    any way interfere, without the concurrence of the occupier
    or manager, with the means and appliances provided for the
    removal of the dust or fumes, and for the carrying out of these
    Regulations.

    These Regulations shall come into force on the 1st day of
    January, 1904.


White Lead

(See also pp. 131 and 132)

In the manufacture of white lead processes which create dust are
specially dangerous, namely, emptying the corrosion chambers, drying and
grinding, transport of the material in the form of powder, and packing.
The following measures are called for: emptying the chambers should only
be done by men wearing respirators or equipped with breathing helmets
after preliminary damping of the corrosions by means of a spray. Use
of a vacuum cleaning apparatus suggests itself. Drying should be done
as far as possible in stoves charged mechanically, the temperature in
which can be watched from the outside; grinding must be done in closed
and ventilated mills; transport of the dried material should be effected
by mechanical means or vacuum apparatus, and packing should be done in
mechanical packing machines. Further, cleanliness and strict discipline
are essential. Alternation of employment is advisable. The question of
substitutes for white lead is referred to on p. 293.

Manufacture of red lead calls for precisely similar preventive measures.
Charging and emptying the oxidising furnaces should be done under
efficient exhaust ventilation. Conveyance, sifting, and grinding of the
cooled material requires to be done in the same way as has been described
for white lead.

In the production of chrome colours (lead chromates) besides the danger
from lead the injurious action of chrome has to be borne in mind.

Regulations for white lead factories have been made in Germany, Belgium,
and Great Britain. We give below the German Imperial Regulations dated
May 26, 1903.

    REGULATIONS FOR MANUFACTURE OF LEAD COLOURS AND LEAD PRODUCTS

    (1) The following regulations apply to all premises in which
    lead colours or other chemical lead products (white lead,
    chromate of lead, masicot, litharge, minium, peroxide of lead,
    Cassel yellow, English yellow, Naples yellow, lead iodide, lead
    acetate, &c., are manufactured), or in which mixtures of lead
    are prepared as the principal or as a subsidiary business.
    They shall not apply to lead smelting works, even though
    processes named in paragraph (1) are carried on.

    Neither shall they apply to workplaces in which manufactured
    colours are intimately mixed or ground in oil or varnish in
    connection with another industry.

    (2) The workrooms in which the materials mentioned in paragraph
    1 are prepared or packed shall be roomy, lofty, and so arranged
    that sufficient and constant exchange of air can take place.

    They shall be provided with a solid and smooth floor permitting
    of easy removal of dust by a moist method. The floor, unless
    for purposes of manufacture, shall be kept constantly wet, and
    shall be wet cleansed at least once daily.

    The walls, when not of a smooth washable surface or painted
    with oil, shall be whitewashed at least once a year.

    (3) The entrance of lead dust, or fumes, into the workrooms
    shall be prevented by suitable means as far as possible. Rooms
    which cannot be thus protected must be so separated from other
    rooms that neither dust nor fumes can enter them.

    (4) Lead melting pots shall be covered with a hood and shaft
    communicating directly or by a chimney with the open air.

    (8)[L] Grinding, sieving, and packing dry lead compounds,
    emptying litharge and minium furnaces, and other operations in
    which lead dust is generated, shall not be done except under an
    exhaust draught, or other efficient means for preventing the
    entrance of dust into the workrooms.

    In the packing of colours containing only a little lead, in
    small amounts, or in small packages for retail purposes,
    exception to these regulations can be allowed by the higher
    authorities.

    (9) Machines generating lead dust and not efficiently protected
    by their construction or method of use against the escape of
    dust, shall have all cracks occluded by means of thick layers
    of felt or similar material, so as to prevent the entrance of
    dust into the workrooms.

    Machines of this kind shall be provided with arrangements
    preventing pressure of the air inside. They shall not be opened
    until they are cool, and until the dust generated has settled.

    (10) Women shall not be employed in factories in which the
    colours specified in paragraph (1) are prepared except in work
    which does not expose them to the action of lead dust or fumes.
    Young persons shall not be employed nor be allowed on the
    premises in factories concerned exclusively or in great part
    with the preparation of lead colours or other lead compounds.

    (11) No person shall be employed in rooms where the processes
    specified in paragraph (1) are carried on who is not provided
    with a certificate from a qualified surgeon stating that he is
    physically fit and free from disease of the lungs, kidneys,
    and stomach, and that he is not addicted to alcohol. This
    certificate shall be kept and produced on demand to the Factory
    Inspector or Appointed Surgeon.

    (12) No person shall be employed in packing lead colours or
    mixtures containing lead or other lead compounds in a dry
    state, or with the coopering of the filled casks for more
    than eight hours daily. This regulation shall not apply where
    the packing machines are provided with effectual exhaust
    arrangements, or so constructed and used as effectually to
    prevent the escape of dust.

    No person under 18 years of age shall be employed in the
    process mentioned in the above paragraph, but exception can
    be allowed in the packing of colours containing lead in
    small amount, or in small packages for retail purposes, on
    application to the higher authorities.

    For the rest, no person coming into contact with lead or lead
    compounds shall be employed for more than 10 hours within the
    space of 24 hours.

    (13) The occupier shall provide overalls and head-coverings for
    all persons coming into contact with lead or lead compounds,
    and suitable footwear for those emptying the oxidising chambers.

    (14) The occupier shall not allow work involving exposure
    to dust to be performed except by workers provided with
    respirators or moist sponges covering the nose and mouth.

    (15) The occupier shall not allow work involving contact with
    soluble salts of lead to be done except by workers provided
    with waterproof gloves or by those whose hands have previously
    been smeared with vaseline.

    (16) The occupier shall provide the overalls, respirators, &c.,
    mentioned in paragraphs (13) (14) and (15) for each one of the
    workers in sufficient number and in good condition. He shall
    take care that they are used only by the workers to whom they
    are severally assigned, and that in the intervals of work and
    during the time when they are not in use they shall be kept in
    their appointed place. Overalls shall be washed every week, and
    the respirators, sponges, and gloves before each time that they
    are used.

    (17) Lavatories and cloak rooms, and, separate from these,
    a mess room, shall be provided for the workers coming into
    contact with lead or lead compounds in a part of the works free
    from dust. These rooms shall be kept in a cleanly condition,
    free from dust, and shall be heated during the cold seasons. In
    the meal room or in some other suitable place there shall be
    means for warming food. The lavatories and cloak rooms shall
    be provided with water, vessels for rinsing the mouth, nail
    brushes for cleaning the hands and nails, soap, and towels.
    Arrangements shall also be made for keeping separate clothes
    worn during work from these taken off before the commencement
    of work. The occupier shall give facilities for all persons
    employed in emptying the oxidizing chambers to have a warm
    bath daily after the end of the work, and for those persons
    coming into contact with lead or lead compounds, twice weekly.
    The time for this shall be during the hours of work, and in
    the cold season the bath room, which must be on the factory
    premises, shall be heated.

    (18) The occupier shall appoint a duly qualified medical
    practitioner, whose name shall be sent to the Inspector of
    Factories and to the Health Authority. He shall examine the
    workers at least twice every month with a view to the detection
    of symptoms of lead poisoning. The occupier shall not employ
    workers suspected of symptoms of lead poisoning in occupations
    exposing them to lead or lead compounds until they have
    completely recovered. Those who appear peculiarly susceptible
    shall be suspended permanently from work.

    (19) The occupier shall keep a book, or make some official
    responsible for its keeping, recording any change in the
    personnel employed in lead or lead compounds and as to their
    state of health. He shall be responsible for the completeness
    and correctness of the entries except those made by the surgeon.

The remaining regulations as to entries in the Health Register, &c., are
similar to those already given in the Regulations for lead smelting works
on p. 300.


Use of Lead Colours

(See also pp. 132-4)

As explained on pp. 132-134 use of lead in the painting and varnishing
trades frequently causes lead poisoning. This has led to regulations in
various countries having for their object partly hygienic measures and
partly also limitation of colours containing lead, such as prohibition of
the use of lead paints in the interior of buildings or in the painting of
public buildings and of ships, &c.

The details of such regulations are seen in the German Imperial
Regulations dated June 27, 1905:

    ORDER OF THE IMPERIAL CHANCELLOR RELATING TO THE PROCESSES
    OF PAINTING, DISTEMPERING, WHITEWASHING, PLASTERING, OR
    VARNISHING. JUNE 27, 1906

    I.—_Regulations for carrying on the Industries of Painting,
    Distempering, Whitewashing, Plastering, or Varnishing._

    _Regulation 1._—In the processes of crushing, blending, mixing,
    and otherwise preparing white lead, other lead colours, or
    mixtures thereof with other substances in a dry state, the
    workers shall not directly handle pigment containing lead,
    and shall be adequately protected against the dust arising
    therefrom.

    _Regulation 2._—The process of grinding white lead with oil or
    varnish shall not be done by hand, but entirely by mechanical
    means, and in vessels so constructed that even in the process
    of charging them with white lead no dust shall escape into
    places where work is carried on.

    This provision shall apply to other lead colours. Provided that
    such lead colours may be ground by hand by male workers over 18
    years of age, if not more than one kilogram of red lead and 100
    grains of other lead colours are ground by any one worker on
    one day.

    _Regulation 3._—The processes of rubbing-down and
    pumice-stoning dry coats of oil-colour or stopping not clearly
    free from lead shall not be done except after damping.

    All _débris_ produced by rubbing down and pumice-stoning shall
    be removed before it becomes dry.

    _Regulation 4._—The employer shall see that every worker who
    handles lead colours or mixtures thereof is provided with,
    and wears, during working hours, a painter’s overall or other
    complete suit of working clothes.

    _Regulation 5._—There shall be provided for all workers
    engaged in processes of painting, distempering, whitewashing,
    plastering, or varnishing, in which lead colours are used,
    washing utensils, nail brushes, soap and towels. If such
    processes are carried on in a new building or in a workshop,
    provision shall be made for the workers to wash in a place
    protected from frost, and to store their clothing in a clean
    place.

    _Regulation 6._—The employer shall inform workers, who handle
    lead colours or mixtures thereof, of the danger to health
    to which they are exposed, and shall hand them, at the
    commencement of employment, a copy of the accompanying leaflet
    (not printed with this edition), if they are not already
    provided with it, and also a copy of these Regulations.

    II.—_Regulations for the Processes of Painting, Distempering,
    Whitewashing, Plastering, or Varnishing when carried on in
    connection with another Industry._

    _Regulation 7._—The provisions of paragraph 6 shall apply to
    the employment of workers connected with another industry
    who are constantly or principally employed in the processes
    of painting, distempering, whitewashing, plastering, or
    varnishing, and who use, otherwise than occasionally, lead
    colours or mixtures thereof. The provisions of paragraphs 8-11
    shall also apply if such employment is carried on in a factory
    or shipbuilding yard.

    _Regulation 8._—Special accommodation for washing and for
    dressing shall be provided for the workers, which accommodation
    shall be kept clean, heated in cold weather, and furnished with
    conveniences for the storage of clothing.

    _Regulation 9._—The employer shall issue regulations which
    shall be binding on the workers, and shall contain the
    following provisions for such workers as handle lead colour and
    mixtures thereof:

      1. Workers shall not consume spirits in any place where work is
      carried on.

      2. Workers shall not partake of food or drink, or leave the
      place of employment until they have put off their working
      clothes and carefully washed their hands.

      3. Workers, when engaged in processes specified by the
      employer, shall wear working clothes.

      4. Smoking cigars and cigarettes is prohibited during work.

    Furthermore, it shall be set forth in the regulations that
    workers who, in spite of reiterated warning, contravene the
    foregoing provisions may be dismissed before the expiration of
    their contract without notice. If a code of regulations has
    been issued for the industry (par. 134a of the G.O.) the above
    indicated provisions shall be incorporated in the said code.

    _Regulation 10._—The employer shall entrust the supervision of
    the workers’ health to a duly qualified medical man approved of
    by the public authority, and notified to the factory inspector
    (par. 139b of the G.O.), and the said medical man shall examine
    the workers once at least in every six months for symptoms
    indicative of plumbism.

    The employer shall not permit any worker who is suffering from
    plumbism or who, in the opinion of the doctor, is suspected of
    plumbism, to be employed in any work in which he has to handle
    lead colours or mixtures thereof, until he has completely
    recovered.

    _Regulation 11._—The employer shall keep or shall cause to be
    kept a register in which shall be recorded the state of health
    of the workers, and also the constitution of and changes in
    the staff; and he shall be responsible for the entries being
    complete and accurate, except in so far as they are affected by
    the medical man.

Then follow the regulations as to entries in the Register, as to which
see the Regulations as to lead smelting works, p. 300.


Type Founding and Compositors’ Work

(See also pp. 138 and 139)

Fumes which may carry up lead dust are generated in the casting of
letters. Dust arises also in setting the type. General hygienic measures
are especially called for such as healthy conditions in the workrooms.
Much can be done by exhaust ventilation locally applied to the type cases
and to letter (mono- and linotype) casting machines. Vacuum cleaning of
printing workshops and type cases is strongly advised.

As some lead poisoning in printing works is attributable to lead colours
or bronze powder containing lead their use should be limited as much as
possible.

The German Imperial Regulations for printing works and type foundries are
as follows:

    ORDER OF THE FEDERAL COUNCIL OF JULY 31ST, 1897, REGULATING
    LETTERPRESS PRINTING WORKS AND TYPE FOUNDRIES, IN PURSUANCE OF
    SECTION 120_E_ OF THE INDUSTRIAL CODE

    I. In rooms in which persons are employed in setting up type
    or manufacture of type or stereotype plates the following
    provisions apply:

      1. The floor of workrooms shall not be more than a half a meter
      (1·64 feet) below the ground. Exceptions may only be granted by
      the higher administrative authority where hygienic conditions
      are secured by a dry area, and ample means of lighting and
      ventilating the rooms.

      Attics may only be used as workrooms if the roof is provided
      with a lathe and plaster ceiling.

      2. In workrooms in which the manufacture of type or stereotype
      plates is carried on, the number of persons shall not exceed
      such as would allow at least fifteen cubic meters of air space
      (529·5 cubic feet) to each. In the rooms in which persons are
      employed only in other processes, there shall be at least
      twelve cubic meters of air space (423·5 cubic feet) to each
      person.

      In cases of exceptional temporary pressure the higher
      administrative authority may, on the application of the
      employer, permit a larger number in the workrooms, for at the
      most 30 days in the year, but not more than will allow ten
      cubic meters of air space (353 cubic feet) for each person.

      3. The rooms shall be at least 2·60 meters (8· feet) in height
      where a minimum of fifteen cubic meters are allowed for each
      person, in other cases at least 3 meters (9·84 feet) in height.

      The rooms shall be provided with windows which are sufficient
      in number and size to let in ample light for every part of the
      work. The windows shall be so constructed that they will open
      and admit of complete renewal of air in workrooms. Workrooms
      with sloping roof shall have an average height equal to the
      measurements given in the first paragraph of this section.

      4. The rooms shall be laid with close fitting impervious
      floor, which can be cleared of dust by moist methods. Wooden
      floors shall be smoothly planed, and boards fitted to prevent
      penetration of moisture. All walls and ceilings shall, if
      they are not of a smooth washable surface or painted in oil,
      be limewashed once at least a year. If the walls and ceilings
      are of a smooth washable surface or painted in oil, they shall
      be washed at least once a year, and the oil paint must, if
      varnished, be renewed once in ten years, and if not varnished
      once in five years.

      The compositors’ shelves and stands for type boxes shall be
      either closely ranged round the room on the floor, so that no
      dust can collect underneath, or be fitted with legs, so that
      the floor can be easily cleaned of dust underneath.

      5. The workrooms shall be cleared and thoroughly aired once at
      least a day, and during the working hours means shall be taken
      to secure constant ventilation.

      6. The melting vessel for type or stereotype metal shall be
      covered with a hood connected to an exhaust ventilator or
      chimney with sufficient draught to draw the fumes to the outer
      air.

      Type founding and melting may only be carried on in rooms
      separate from other processes.

      7. The rooms and fittings, particularly the walls, cornices,
      and stands for type, shall be thoroughly cleansed twice a year
      at least. The floors shall be washed or rubbed over with a damp
      cloth, so as to remove dust once a day at least.

      8. The type boxes shall be cleansed before they are put in use,
      and again as often as necessary, but not less than twice at
      least in the year.

      The boxes may only be dusted out with a bellows in the open
      air, and this work may not be done by young persons.

      9. In every workroom spittoons filled with water and one at
      least for every five persons shall be provided. Workers are
      forbidden to spit upon the floor.

      10. Sufficient washing appliances, with soap and at least one
      towel a week for each worker, shall be provided as near as
      possible to the work for compositors, cutters, and polishers.

      One wash-hand basin shall be provided for every five workers,
      fitted with an ample supply of water.

      The employer shall make strict provision for the use of the
      washing appliances by workers before every meal and before
      leaving the works.

      11. Clothes put off during working hours shall either be kept
      outside the workroom or hung up in cupboards with closely
      fitting doors or curtains, which are so shut or drawn as to
      prevent penetration of dust.

      12. Artificial means of lighting which tend to raise the
      temperature of the rooms shall be so arranged or such
      counteracting measures taken that the heat of the workrooms
      shall not be unduly raised.

      13. The employer shall draw up rules binding on the workers
      which will ensure the full observance of the provisions in
      sections 8, 9, 10, and 11.

    II. A notice shall be affixed and a copy sent to the local
    police authority shewing:

      (_a_) The length, height, and breadth of the rooms.

      (_b_) The air space in cubic measure.

      (_c_) The number of workers permitted in each room.

      A copy of Rules 1 to 13 must be affixed where it can be easily
      read by all persons affected.

    III. Provides for the method of permitting the exceptions
    named above in sections 2 and 3, and makes it a condition of
    reduction in cubic air space for each person employed as type
    founder or compositor that there shall be adequate mechanical
    ventilation for regulating temperature and carrying off
    products of combustion from workrooms.


Ceramic Industry

(See also pp. 135-8.)

A complete substitute for lead in glazes seems as yet impossible on
technical grounds, as glaze containing lead has qualities which cannot
be obtained without its use. In small works the technique necessary
for the production of leadless glazes (special kinds of stoves) cannot
be expected, especially as those carrying on a small industry lack the
necessary knowledge of how to be able to dispense with the use of lead
glazes and substitute leadless materials without complete alteration
in their methods of manufacture. And yet discontinuance or the utmost
possible limitation of the use of lead glazes and colours is most
urgently needed in all small ceramic workshops, as they are not in a
position to put in localised exhaust ventilation, &c., which is possible
in large factories. Observance of even the simplest hygienic measures can
scarcely be obtained. Consequently very severe cases of lead poisoning
are met with in small works. An effort in the direction of discontinuance
of lead glazes was made in Bohemia, where (at the cost of the State)
technical instruction was given by an expert on the preparation of
leadless glazes especially in districts where the industry was carried
on in the homes of the workers. This procedure, extension of which is
expected, had good results.

Many have demanded, in view of the possibility of substituting leadless
for lead glazes, the total prohibition of lead. Such is the view of the
Dutch inspector De Vooys; Teleky and Chyzer share the view expressed so
far as the small industry is concerned, since the practicability of the
change has been demonstrated.

English authorities (Thorpe, Oliver) propose diminution of the lead in
the glaze in such a way that on shaking with weak acid not more than a
specified small quantity shall be dissolved (Thorpe test). In my opinion
such a measure is hardly enough for the small industry. I do not expect
much good from obligatory use of fritted glazes.

In addition to earthenware, manufacture of tiles and bricks leads not
infrequently to cases of lead poisoning from use of lead glaze.

The following measures apply to the larger ceramic works. Since risk
is considerable, not only in glost placing but also in grinding,
ware-cleaning, &c., closed ball mills in grinding and locally applied
exhaust ventilation in ware-cleaning operations, &c., must be arranged.
Personal cleanliness and proper equipment of a factory in all the
essentials insisted on on pp. 226-9 are important, but nothing can take
the place of efficient locally applied ventilation.

Vitreous enamelling of household utensils, baths, gas stoves, signs,
&c., is an analogous process as enamels containing lead may be used.
Sieving on the dry powder and brushing off superfluous glaze often cause
poisoning. Here generally the same preventive measures apply.

[In Great Britain the china and earthenware industry is placed under
Regulations dated January 2, 1913, which supersede the previous Special
Rules. These Regulations—thirty-six in number—provide, among other
usual provisions, (1) for efficient exhaust ventilation in (_a_)
processes giving rise to injurious mineral dust (fettling and pressing
of tiles, bedding, and flinting, brushing and scouring of biscuit)
and (_b_) dusty lead processes (ware cleaning, aerographing, colour
dusting, litho-transfer making, &c.); and (2) monthly periodical medical
examination of workers in scheduled lead processes.]

In the Netherlands, in consequence of lead poisoning in porcelain works,
committees were appointed to inquire into the subject in 1901, 1902, and
1903.


File Cutting

(See also p. 140)

In file cutting the file is cut on a lead bed or a bed of an alloy of
zinc and lead. The same source of poisoning occurs in other industries
such as amber working. Lead poisoning among file cutters is pronounced.
The best preventive measure is substitution of a bed of pure zinc for
lead. The German Imperial Health Office have issued a ‘Warning notice’
for file-cutters.

    LEAFLET FOR FILE-CUTTERS

    The use of lead beds or of alloys of lead with other metals
    has repeatedly brought about lead poisoning in file-cutters.
    The beds also supposed to be made of zinc usually contain a
    considerable proportion of lead, and are thus dangerous to
    health.

    Among file-cutters lead poisoning arises from absorption of
    the metal in small quantities by means of dirty hands, eating,
    drinking, smoking or chewing of tobacco. The consequences of
    this absorption are not at once noticeable. They appear only
    after weeks, months, or even years, according to the extent to
    which the lead has accumulated in the system.

    _How does lead poisoning show itself?_—The first sign is
    usually a bluish-grey line on the gums called the blue line,
    associated with anæmia or pallor. Later symptoms are very
    varied. Most frequently lead colic comes on, the affected
    person suffering from violent cramplike pains starting from the
    navel; the stomach is hard and contracted; very often vomiting
    and constipation ensue, or, very occasionally, diarrhœa. In
    some cases paralysis shows itself—generally in those muscles
    which extend the fingers, usually affecting both arms. In
    exceptional cases other muscles of the arms and legs are
    affected. Sometimes lead poisoning manifests itself in violent
    pains in the joints—generally the knee, more rarely in the
    shoulder and elbow. In specially severe cases brain trouble
    supervenes—violent headache, convulsions, unconsciousness or
    blindness. Finally lead poisoning may set up disease of the
    kidneys—Bright’s disease and gout.

    Women suffering from lead poisoning frequently miscarry.
    Children born alive may, in consequence of lead poisoning, die
    in their first year. Children fed at the breast are poisoned
    through the milk.

    Apart from severe cases complicated with brain trouble,
    which are often fatal, persons suffering from lead poisoning
    generally recover if they withdraw from further contact.
    Recovery takes place after a few weeks, but in severe cases
    only after months.

    The most effective preventive measures are cleanliness
    and temperance. Persons who, without being drunkards, are
    accustomed to take spirits in quantity are more likely to
    succumb than the abstemious. Spirits should not be taken
    during working hours. In regard to cleanliness, file-cutters
    using lead beds should be especially careful and observe the
    following rules:

    1. Since soiling the hands with lead cannot be entirely
    avoided, smoking and chewing tobacco during work should be
    given up.

    2. Workers should only take food and drink or leave the works
    after thoroughly washing the hands with soap—if possible with
    pumice stone; if drinking during work cannot be wholly given up
    the edges of the drinking vessels ought not to be touched by
    the hands.

    If a file-cutter falls ill in spite of precautions with
    symptoms pointing to lead poisoning he should, in his own and
    his family’s interest, at once consult a doctor, telling him
    that he has been working with a lead bed.


Other Industries in which Lead is used

In cutting _precious stones_ with use of lead discs lead poisoning
frequently occurs, especially where this trade, as in some parts of
Bohemia, is carried on as a home industry. The authorities have required
substitution of carborundum (silicon carbide) for lead discs. As,
therefore, an efficient substitute is possible, use of lead should be
prohibited. Similarly, use of lead in the making of musical instruments
should, if possible, be discontinued. Brass pipes in _musical instrument_
making are filled with lead to facilitate hammering and bending, and in
this way poisoning has occurred. In numerous other industries where the
use of lead cannot be avoided, and where consequently the danger must
be present, as, for instance, in _lead melting_, _soldering_, _lead
rolling_, _stamping_, _pressing_, &c., in the manufacture of _lead
piping_, _shot_, _wire_, _bottle capsules_, _foil_, _toys_, and many
other articles, general preventive measures should be carefully carried
out. _Melting of lead_ and _lead alloys_ should be carried out only under
efficient exhaust ventilation. In larger works where dust is generated
this should be drawn away at the point where it is produced. This applies
also to processes in the chemical industries where lead or lead compounds
are used, seeing that no substitute is possible.


Zinc, Brass-casting, Metal Pickling, Galvanising

(See also pp. 151 and 182)

In zinc smelting account has to be taken of fumes which may contain
lead, zinc, arsenic, sulphur dioxide, and carbonic oxide. Metallic fumes
require to be condensed—a procedure in harmony with economic interests.
This is effected in a technically arranged condensing system, consisting
of a condenser and prolong, in which the fumes are given as large a
space as possible in which to condense and cool. In order to prevent
the entry of fumes into the shed when removing distillation residues,
hoods should be arranged over the front of the furnace through which
the gases can be conducted into the main chimney stack or be drawn away
by a fan; in addition the residue should fall into trolleys which must
either be covered at once or placed under a closely fitting hood until
the fuming contents are cool. As the mixing of the materials for charging
and the sifting and packing of the zinc dust (poussière) may cause risk,
these processes require to be carried out mechanically with application
of local exhaust. Such an arrangement is shown in fig. 59 below. The
material which is fed in is carried by the elevator to the sifting
machine, falls into the collecting bin, and is then packed. The points at
which dust can come off are connected with the exhaust and carried to the
dust collector; fans carry the filtered air to the outside atmosphere.

[Illustration: FIG. 59.—Arrangement for Sieving and Packing Zinc Dust
(poussière).

_a_ Charging hopper; _b_ Distributor; _c_ Elevator; _d_ Sieve; _e_
Collector; _f_ Packing machine; _g_ Exhaust pipe; _h_ Worm; _i_ Dust
Collector; _k_ Motor]

Only paragraphs 3-8 of the German Imperial Regulations dated February 6,
1900, for Spelter Works are quoted, as the remainder are on precisely
similar lines to those for lead smelting works given in full on p. 300.

    3. Crushing zinc ore shall not be done except in an apparatus
    so arranged as to prevent penetration of dust into the workroom.

    4. The roasting furnaces as well as the calcining furnaces
    shall be provided with effective exhaust arrangements for the
    escaping gases. The occupier shall be responsible for their
    efficiency during the time the furnace is at work.

    5. To avoid dust, ores intended for charging distillation
    furnaces shall not be stacked in front of or charged into
    the furnace, or mixed with other material, except in a damp
    condition.

    This regulation shall not apply to large so-called Silesian

    Retorts when in use in the zinc smelter; yet in the case of
    them also the Higher Authorities may require damping of the
    charging material if specially injurious to health.

    6. Dust, gases and vapours escaping from distillation furnaces
    shall be caught as near as possible to the point of origin by
    efficient arrangements and carried out of the smelting rooms.
    The entrance of the gases from the fires into the smelting room
    shall be prevented as far as possible by suitable arrangements
    for drawing them off.

    7. Residues shall not be drawn into the smelting room; they
    shall be caught in closed channels under the furnaces and
    emptied from these channels at once into waggons placed in
    passages beneath the distillation rooms.

    This regulation (where the Higher Authorities approve) shall
    not apply to existing plants, should it be impossible to make
    the arrangements mentioned in Reg. 1, or where such additions
    could only be added by rebuilding at a prohibitive cost.

    8. Sieving and packing of by-products obtained by the
    distillation of zinc (poussière, flue dust) shall not be done
    except in a special room separate from other workrooms, in
    accordance with Reg. 1.

    Sieving shall only be done in an apparatus so arranged as to
    prevent escape of dust.

In _brass casting_, in order to prevent occurrence of brass-founders’
ague, it is necessary that the zinc oxide fumes evolved should be
effectively drawn away from the crucible by locally applied exhaust
ventilation. General ventilation merely of the room is almost useless, as
in casting the fumes rise up into the face of the pourer. Seeing that
casting is carried on in different parts of the foundry, it is advisable
to connect up the hoods over the moulds by means of metal piping with the
exhaust system, or to arrange a flexible duct which can be moved about as
occasion requires.

Dangerous acid fumes (notably nitrous fumes) are evolved in metal
pickling, especially of brass articles (such as harness furniture,
lamp fittings, church utensils, &c.), for the purpose of giving them a
shiny or dull surface by immersion in baths of nitric, hydrochloric, or
sulphuric acid. As severe and even fatal poisoning has occurred in these
operations they should be conducted in isolated compartments or channels
under exhaust ventilation. If the ventilation provided is mechanical an
acid proof earthenware fan or an injector is necessary. The following
description applies to one large works: The pickling troughs are placed
in a wooden compartment closed in except for a small opening in front.
To this compartment a stoneware pipe leading to a stoneware fan is
connected. The nitrous fumes are drawn through the pipe and led into
the lower part of an absorption tower filled with cone-shaped packing
material through which water trickles from a vessel placed at the top.
The greater part of the acid fumes are absorbed as they pass upwards
and the water collects in a receiver below, from which it is blown by
compressed air into the vessel above for utilisation again until it
becomes so charged with acid that it can be used for pickling purposes.

In _galvanising_ and _tinning_ acid fumes, injurious acroleic vapour, and
metallic fumes can arise as the metal articles (iron, copper, &c.) first
require to be cleaned in an acid bath and then dipped into molten fat
or molten zinc or tin. Here also the fumes should be drawn away in the
manner described.


Recovery and Use of Mercury

Escape of mercury vapour and development of sulphur dioxide seriously
endanger workers engaged in smelting cinnabar. The danger can be
minimised by proper construction of furnaces preventing escape as far
as possible of fumes and most careful condensation of the mercury in
impervious and sufficiently capacious chambers and flues.

Continuous furnaces are to be preferred to those working intermittently.
The system of condensing chambers and flues must offer as long a passage
as possible to the fumes, and care must be taken to keep them thoroughly
cool. Removal of the deposit rich in mercury from the flues is especially
fraught with danger. This work should only be carried on after efficient
watering by workers equipped with respirators, working suits, &c.

_Use of mercury._—Mirror making by coating the glass with mercury used
to be one of the most dangerous occupations. Now that a fully adequate
substitute for mercury has been found in the nitrate of silver and
ammonia process, use of mercury should be prohibited. As a home industry
especially mirror coating with mercury should be suppressed. Fortunately
the dangerous mode of production is rapidly being ousted.

The following requirements are contained in a decree of the Prussian
Government dated May 18, 1889:

(1) Medical certificate on admission to employment in mirror making with
use of mercury;

(2) restriction of hours to six in summer and in winter to eight daily,
with a two hours’ mid-day interval;

(3) fortnightly examination of the workers;

(4) air space per person of 40 cubic meters in the coating room and 30 in
the drying room, and, in both, introduction of 60 cubic meters of air per
head per hour;

(5) Work to cease if the temperature of the room in summer reaches 25° C.

Measures are necessary to prevent occurrence of mercury poisoning in
hatters’ furriers’ processes (preparation of rabbit fur for felt hats)
in consequence of the use of nitrate of mercury. Danger arises chiefly
in cutting the hair, in dressing and drying, in sorting, and also in
the subsequent stages of hard felt hat manufacture. Aspiration of the
dust and fluff at its point of generation, isolation of the drying
rooms and prohibition of entry into them while drying is going on, are
necessary. In dressing (commonly known as ‘carotting’), the nitric acid
vapour requires to be drawn away. In addition strict personal hygiene,
especially of the teeth, is very important. Processes involving _water
gilding_ (nowadays practised on a very small scale) should only be
carried on in stoves provided with exhaust ventilation. Electroplating,
fortunately, has almost entirely taken its place.

As cases of mercury poisoning have been reported from use of mercurial
pumps in producing the vacuum inside _electric incandescent bulbs_, air
pumps should be substituted for them whenever possible.

_Barometer_ and _thermometer_ makers may and do suffer severely if care
is not taken to draw away the fumes and ensure good ventilation of the
workrooms. Careless handling and the dropping of mercury on the benches
make it difficult to prevent some volatilisation. Personal hygiene and
especially a proper hygiene of the mouth are of the greatest importance
in this class of work.

Preparation of mercury compounds in chemical factories, especially the
dry processes (sublimation), as in production of cinnabar, corrosive
sublimate and calomel mixing, grinding, and sublimation, require to be
carried on in closed apparatus. Preparation of the substances named above
in solution involves much less risk than subliming. From our point of
view, therefore, the former is to preferred.


Arsenic, Arsenic Compounds, Arseniuretted Hydrogen

For arsenic works imperviousness of the system and as complete
condensation as possible are necessary to prevent escape of fumes.

Respirators should be worn in manipulations with white arsenic, and
such work as packing done under conditions of locally applied exhaust
ventilation.

Industrial use of arsenic compounds, in view of the risk attaching to
them, should be reduced as much as possible. This has sometimes been
achieved by technical improvement in processes of manufacture. Thus in
the colour industry, where formerly colours containing arsenic played
an important rôle, coal-tar colours have taken their place, and use
of arsenic even in these (as in the manufacture of fuchsin) has been
replaced by nitrobenzene.

As the danger from arseniuretted hydrogen gas is especially great in
processes in which acid acts on metal and either one or both of them
contain arsenic, the materials, should be as free from arsenic as
possible, in the production, for example, of hydrogen for soldering, in
extracting metals by means of acids, in galvanic elements, in accumulator
works, in the storage and transport of acids in metal vessels, and in
galvanising.

In any case the workers in these industries should be warned of the
danger and instructed in case of emergencies. For soldering exclusive use
of hydrogen produced electrolytically and procurable in steel cylinders
is advisable.


Extraction and Use of Gold and Silver

In the extraction of gold and silver by amalgamation and subsequent
volatilisation of mercury there is risk of mercurial poisoning. The
preventive measures necessary are similar to those for poisoning in the
recovery of mercury (see p. 327).

_Argyria_ in pearl bead blowers can be avoided by using pumps to blow the
silver solution into the beads instead of the mouth.

In electroplating the possibility of poisonous fumes arising from the
baths must be guarded against because hydrocyanic (prussic) acid, though
only in minute quantities, may be evolved; care must be taken that the
workrooms are well ventilated or the baths hooded. Careful personal
hygiene is essential, for the prevention of skin diseases from which
workers in electroplating often suffer.




VII

_PREVENTIVE MEASURES IN OTHER TRADES_


Ceramic Industry

In the glass industry use of lead, chrome, and arsenic compounds should
be restricted as much as possible or allowed only under suitable
precautions (exhaust ventilation, personal hygiene, &c.).

_Etching on glass_ by means of hydrofluoric causes almost inevitably
injury to the workers. Rendering the surface of glass opaque should
preferably be done by sand blast. When a bath of hydrofluoric acid for
etching on glass is used the fumes require to be drawn away by hoods over
the baths and the work-rooms well ventilated.

Further precautionary measures are called for in view of industrial
poisoning by furnace gases in various ceramic industries, as, for
example, cement works, glass works, and tile works.

The following suggestions are made in the technical introduction to the
Germany Factory Act for prevention of poisoning from carbonic oxide,
carbon dioxide, and sulphur dioxide:

(1) Even the fixing of benches which might be used for sleeping on near
the furnaces should be strictly forbidden;

(2) All furnaces which are roofed over should be provided with adequate
side and roof ventilation;

(3) All gas pipes and cocks must be maintained in an impervious condition.


Manufacture and Use of Varnishes and Drying Oils

Unpleasant fumes are given off on boiling linseed oil with oxidising
substances, which should be prevented by closely fitting covers and
condensation of the fumes in cooling apparatus. In heating and dissolving
resin for the production of varnishes the fumes evolved require to be
dealt with in a similar way.

Preventive measures must be taken also in the use of quick-drying paints
on ships and inside steam boilers as, owing to the rapid evaporation of
the poisonous solvents—benzene, benzine and turpentine—fatalities have
occurred. As a result of elaborate investigation by the inspectors of
factories in Hamburg the following instructions were issued:

    Quick-drying paint for ships and for preventing rust should
    only be used under the supervision of a person conversant with
    the danger to health and risk from fire.

    They should only be allowed for the painting of interior
    surfaces after adoption of adequate precautions—free
    ventilation, use of smoke helmets with air conducting
    apparatus, and no naked lights, &c. Since use of quick-drying
    paints cannot easily be prohibited and the fumes from the
    substitutes for turpentine—benzene and other light tarry
    oils—exert injurious effect on man, precautionary measures are
    called for. Regulation of working hours is as important as
    provision of adequate ventilation. Workers, therefore, should
    be allowed proper intervals from work.

    Confined spaces in the interior of ships should be adequately
    ventilated before, after, and during work; all persons who use
    the paints should have opportunity for washing given them at
    their work places, and should be compelled to avail themselves
    of these facilities; indulgence in alcohol and smoking should
    be prohibited; receptacles in which quick-drying paints are
    sold should be provided with an air-tight cover and with a
    warning notice as to the danger of the contents.

    Paints made from petroleum fractions of low boiling-point,
    light coal-tar oils, turpentine oil, carbon bisulphide, and
    similar substances, are to be regarded as injurious to health.

    Persons under eighteen, and women, should not be allowed to
    work with quick-drying paints.

    Obligatory notification of cases of poisoning by hydrocarbons
    and other similar poisonings would have a good effect.

Schaefer (Inspector of Factories in Hamburg) has drawn up the following
leaflet for painters, varnishers, workers in dry docks, and others
engaged in painting with quick drying paints and oils:

    All quick-drying paints and oils are more or less injurious
    to health and very inflammable, as they contain volatile
    substances such as benzine (naphtha, petrol ether), benzene,
    turpentine oil, carbon bisulphide, &c. These paints are mostly
    used in painting interiors of ships, boilers, machinery,
    apparatus, &c., and come on the market under various
    names, such as Black Varnish Oil, Solution, Patent Colour,
    Anti-corrosive, Dermatin, Acid-proof Paint, Apexior, Saxol, &c.

    Even at ordinary temperatures the volatile fluids used
    as mediums for dry paint powders, or as a first coating,
    evaporate. Air filled with the fumes is not only harmful to
    health, but liable to explosion. Working with these paints and
    oils in the interior of ships, or steam boilers and the like,
    has repeatedly led to explosions and fatal poisoning.

    _Danger of Poisoning._—All persons are exposed to the danger of
    poisoning who use quick-drying paints in the interior of rooms
    or receptacles, or otherwise manipulate the paints. The warmer
    the room and the less ventilation there is before and during
    the painting, the greater the danger of poisoning. On the other
    hand, use of these paints in the open air is generally without
    effect.

    Poisoning arises from inhaling the fumes of hydrocarbons.
    The symptoms are oppression, headache, inclination to vomit,
    cough, hiccough, giddiness, noises in the ears, drunken-like
    excitement, trembling and twitching. Inhalation of larger
    quantities brings on, quite suddenly and without previous
    warning, unconsciousness, which may last many hours and is
    often fatal. Except in severe cases the symptoms generally
    soon disappear, if the affected person withdraws from further
    contact with the fumes. The most effective protection therefore
    against poisoning is fresh air and temperance. In so far as
    painting with quick-drying materials is necessary in workrooms,
    interiors of ships, water and ballast tanks, double bottoms,
    bunkers, bilges, cabins, boilers and receptacles, care must
    be taken to ensure thorough ventilation before, after, and
    while the work is going on. Where no sufficient ventilation
    is possible these paints ought not to be used. Frequent
    intermission of work by a short stay in the open air is useful.
    When working in spaces not easily accessible, the worker should
    be roped.

    Speaking, singing, or whistling during work favours inhalation
    of the fumes and is, therefore, to be avoided. Indulgence in
    spirits, especially during working hours, increases the danger
    of poisoning. Habitual drinkers should not be allowed to work
    at all with quick-drying paints and oils.

    At the first signs of discomfort work should be stopped. An
    immediate stay in the open air will then usually dispel the
    poisonous symptoms.

    If, notwithstanding this, severe symptoms develop, oxygen
    inhalation should be commenced forthwith and medical aid called
    in.


Production of Vegetable Foods and Luxuries

(See also p. 154)

Measures for the prevention of industrial poisoning have to be thought of
in connection with drying processes (by smoke gases, carbon dioxide, and
carbonic oxide), many processes of preserving (use of sulphur dioxide,
&c.), and fermentation (accumulation of carbonic acid).

In breweries the use of kilns allowing fire gases to enter the
drying-rooms formerly caused carbonic oxide and carbonic acid poisoning.
The general introduction of hot air kilns provided with mechanical
malt-turning apparatus should be insisted on, and is in keeping with
progress in technical methods.

The accumulation of carbonic acid in the malting cellars can be prevented
in the same way as in a distillery.

If ammonia is used for _refrigeration_, precautions are necessary so
that, in the event of leakage or bursting of pipes, the workers may
escape. Naturally the imperviousness of the freezing system must be
guaranteed.

Oppression and danger to the health of the workers is occasionally caused
by the development of gases in the coating of barrels with pitch, partly
preventable by the use of pitching machines.

In the production of _spirits_ carbonic acid poisoning can occur from
accumulation of carbonic acid in the fermentation cellars. These should
be thoroughly ventilated and in view of the heaviness of the gas,
openings for ventilation should always be located at the floor level.

In the _sulphuring of malt_ the following recommendations were made by
the Austrian inspectors:

During the sulphuring process the room ought not to be entered (for
the turning over of the malt). When the sulphur has been burnt, the
drying-room must be ventilated from the outside, by opening the windows
and letting in cold currents of air, until the sulphur dioxide has
completely dispersed, which can be tested by holding a strip of moistened
blue litmus paper at the half-opened door. If it does not turn red,
turning over of the malt may be proceeded with.

As the _sulphuring of hops_ in hop districts is done in primitive little
kilns, in which the hops are spread out on a kind of gridiron and sulphur
burnt below in iron pans, development of sulphur dioxide may affect the
workers. The following regulations are therefore suggested for work in
these kilns:

    The rooms in which sulphuring takes place must be airtight,
    capable of being locked, and provided with arrangements which
    make it possible to remove the sulphur dioxide fumes before
    the room is entered. This can usually be done by a strong
    coke fire, maintained in the chimney place, which creates the
    necessary draught. If fans are used, it must be remembered that
    iron is affected and destroyed by acid gases; stoneware fans
    are therefore advisable.

In the production of _vinegar_, air escapes laden with acetic acid
vapour, alcohol, lower oxidation products of alcohol, aldehyde, acetic
ether, &c. Their escape can be avoided if the whole process is carried on
in a closed self-acting apparatus with the advantage also that no loss
occurs.

In premises for _drying agricultural products_ (fruit, chicory, turnips)
the persons employed in the drying-room are exposed to the danger of
carbonic oxide poisoning from direct firing.

The following recommendations for work in drying-rooms with direct firing
are taken from an Austrian decree of 1901:

    The lower drying chambers, in which the real drying process
    is effected, should be so arranged that the objects dried in
    them can be removed by means of long-handled implements through
    a passage shut off from the drying-room. The separation of
    this passage can be effected by loose tin plates which can be
    removed as required for the work of turning or removal of the
    dried products, so that the worker need not come into contact
    with the gases.

    Open fires should be so arranged that if required they can
    be shut off, by simple arrangements, from the drying-rooms
    in which the workers are temporarily occupied in carrying
    in, and turning, the objects to be dried, transferring the
    partly dried products to hotter hurdles, and emptying them
    when finished, in such a way that the entrance of combustion
    gases into the drying chambers can be completely prevented. In
    order, however, to prevent a back draught, arrangements must be
    made for simultaneous removal of the gases by pipes connected
    with a chimney or smoke flue. The places from which the fires
    are charged should, in addition, be furnished with suitably
    arranged openings for ventilation leading into the outer air,
    in order to neutralise, in case of need, any back draught from
    the furnaces into the rooms.

    The windows of the drying chambers should be so arranged as to
    open both from within and without.

    The floor of the roof space, or attic, which forms at the same
    time the ceiling of the upper drying-room, should be kept
    perfectly airtight, as also the openings into it through which
    the steam pipes pass. For this purpose the floor should be a
    double one and the openings or boxes into which material is
    thrown should have a double cover above and below. Further,
    situated in the highest point of the ceiling of the roof space,
    there should be a suitable number of openings topped by louvred
    turrets. In the roof space no work should be done except
    manipulations necessary for the charging of the hurdles with
    the goods to be dried. Use of the roof floor as a sleeping or
    living room is not permissible.

    Before the workers enter the drying chambers for the purpose of
    turning the materials, the stove should be shut off, the gases
    drawn from the furnace into the chimney or flue, and at the
    same time the doors and windows of the drying rooms opened.

    Entering of drying chambers for working purposes should only be
    done after a sufficient time has elapsed for removal of the air
    by ventilation.

    Charging of the furnaces should be so arranged that they burn
    as low as possible before the removal of the dried materials
    and before subsequent work in the drying chambers. Seeing that
    chicory and turnip drying is done intermittently by night, a
    special sleeping or waiting room with free ventilation should
    be provided. The regulations concerning the ventilation of the
    workrooms are to be made known to the workers.


Cigar Industry

In order to prevent injury to health to tobacco workers the dust and
fumes, especially at cutting and sifting machines, require to be drawn
away by locally applied exhaust ventilation. The workrooms, moreover,
must conform to hygienic requirements, especially as to cleanliness.
Washing accommodation and baths are desirable, but are only likely to be
provided in large works.


Wood Working

(See also p. 154)

Risk from poisonous woods can be avoided by exhaust ventilation applied
to the wood-working machinery.

To lessen the danger to health in the use of methylated spirits in the
polishing of wood adequate ventilation of the workrooms is necessary;
drawing off the fumes by local ventilation is often impossible.


Production of Wood-pulp (Cellulose) and Paper.

In the _sulphite cellulose_ process, sulphur dioxide may escape from
the sulphur stoves or from the boilers; escape of sulphur dioxide is
also possible through defective gas pipes and condensers. Gas pipes and
condensers require to be quite impervious and condensation or absorption
as complete as possible. The fumes escaping from the boilers should be
led through pipes into closed boilers for condensation purposes; the
gases not condensed here are to be led into absorption towers.

In the manufacture of _paper_ with use of chloride of lime for bleaching
chlorine can be given off in considerable quantity, requiring removal of
the gases from the apparatus.

The use of poisonous colours containing lead or arsenic, and addition of
lead-containing substances to the paper pulp, is now very rare.


Textile Industries.

(See also p. 156)

In the textile industry only a few manipulations are associated with
serious risk of poisoning. Those engaged in carbonising are exposed
to acid fumes; closed and ventilated apparatus, therefore, as far as
possible, require to be used and the acid gases escaping from them should
be absorbed. These requirements are fulfilled by carbonising stoves which
are ventilated and connected with coke condensers. It is especially urged
that only arsenic free acid be employed, as otherwise danger of poisoning
by arseniuretted hydrogen may be incurred.

In the making of _artificial silk_, according to the Chardonnet-Cadoret
process, the precautionary measures recommended in nitrating together
with careful exhaustion of the ether and camphor fumes apply.

The combustion gases (containing carbonic oxide) developed in the
process of singeing are harmful and require to be led away at their
source.

Poisonous metallic salts, especially lead and lead-containing zinc, are
used as weighting materials, in dressing or finishing, and sometimes
cause symptoms among the workers. Apart from the danger to those occupied
in spinning and weaving, the workers who handle these products (in the
clothing trade) also run a risk from lead.

Precautionary measures are necessary in the _varnishing of woven
materials_, as the substances employed may contain volatile poisonous
solvents. If these poisonous solvents cannot be replaced by others less
poisonous, carefully applied exhaust ventilation must be provided.
The same holds good when carbon bisulphide, benzene, and benzine are
used as solvents in the production of woven materials impregnated with
indiarubber.

Employment of lead salts and other poisonous metallic salts in the
glossing of woven materials, or in order to render them non-inflammable,
is to be deprecated.

Cases of lead poisoning have occurred in the working-up of asbestos, as
lead wire is sometimes used in the process of weaving.

To protect workers in _chlorine_ and _sulphur bleaching_ from poisoning
by chlorine or sulphur dioxide the gases arising from the bleaching
liquids should be drawn away. Use of closed bleaching apparatus, as is
the case in large works, reduces the danger to a minimum. Bleaching-rooms
should be connected with a powerful stoneware fan, so that they may be
thoroughly aired before they are entered.


Dye Works

Industrial poisoning by dyes is, in general, rare, as the natural dyes
(wood and tar dyes) are almost without exception non-poisonous. Further,
the dyes are generally only used in diluted solution. Formerly the
arsenic in many tar dyes caused poisoning, but now it is usually the
mordants which have harmful effect. To this class belong chromic acid
salts and mordants containing arsenic, antimony (tartar-emetic), and
also chloride of tin. In the scraping off of layers of paint containing
arsenic, arsenic dust may arise. In Turkey red dyeworks, especially
sodium arsenite is used for fixing the tar dyes.

Orpiment dyes which may give off poisonous arseniuretted hydrogen gas
are becoming less and less used; from the point of view of industrial
hygiene, the utmost possible avoidance of the use of arsenic-containing
preparations in dye works is to be recommended. Where this is not
possible, strict personal hygiene must be enforced (as, for instance,
application of vaseline to the skin).




FOOTNOTES


[A] Leymann has dealt with the conditions of health in a large aniline
factory in a later work which is referred to in detail in the section on
the aniline industry.

[B] Poisoning by lead, phosphorus, and arsenic contracted in a factory or
Workshop has been notifiable in Great Britain and Ireland since 1895.

[C] ‘On the Nature, Uses, and Manufacture of Ferro-silicon,’ 1909, Cd.
4958.

[D] In Great Britain section 73 of the Factory and Workshop Act, 1901,
requires every medical practitioner attending on or called in to visit
a patient whom he believes to be suffering from lead, phosphorus,
arsenical or mercurial poisoning, or anthrax, contracted in any factory
or workshop, to notify the Chief Inspector of Factories, and a similar
obligation is placed on the occupier to send written notice of every case
to the inspector and certifying surgeon of the district.

The table on p. 222 shows the number of reports included in returns for
the years 1900-12.

Cases of acute poisoning in factories and workshops are reportable to
the Inspector and certifying surgeon, under the Notice of Accidents Act,
1906, when (_a_) causing loss of life or (_b_) due to molten metal, hot
liquid, explosion, _escape of gas_ or steam, and so disabling any person
as to cause absence throughout at least one whole day from his ordinary
work.

The following table gives indication of the relative frequency of cases
of poisoning from gases and fumes, although some were reported as
accidents the result of the unconsciousness induced:

    +-------------------------------+-------+------+------+------+------+
    |     Nature of Gas or Fumes.   | 1912. | 1911.| 1910.| 1909.| 1908.|
    |              (1)              | (2)   |  (3) |  (4) |  (5) |  (6) |
    +-------------------------------+-------+------+------+------+------+
    |Carbon monoxide                |91 (14 |64 (6 |53 (9 |53 (6 |55 (5 |
    |  (_a_) Blast furnace          |33  (5 |16 (2 |19 (7 |16    |26 (3 |
    |  (_b_) Power (suction,        |       |      |      |      |      |
    |    producer, Mond, Dowson).   |19  (4 |31 (1 |25    |25 (4 |19 (2 |
    |  (_c_) Coal                   |29  (2 | 6 (2 | 4    |11 (1 | 9    |
    |  (_d_) Other                  |10  (3 |11 (1 | 5 (2 | 1 (1 | 1    |
    |Sulphuretted hydrogen          | 6     | 8 (2 | 2    | 5 (2 | 8 (1 |
    |Carbon dioxide                 | 3  (2 | 1 (1 | 2 (1 | 2 (2 | 4 (3 |
    |Ammonia                        | 1     | 1 (1 | 2    | 1    | 1    |
    |Chlorine and hydrochloric      |       |      |      |      |      |
    |  acid fumes                   | 3     | 5 (1 | 3    | 1    | 1    |
    |Nitrous fumes                  |12  (1 |18 (2 |11    |12 (2 | 3 (1 |
    |Nitro and amido derivatives of |       |      |      |      |      |
    |  benzene                      | 9  (1 |21    |18    | 4    | 2    |
    |Naphtha and benzene            | 3  (1 | 1 (1 | —    | 1 (1 | 2    |
    |Other (Sulphur dioxide, &c.)   | 7  (2 | 4    | 4    | 4    | 3    |
    +-------------------------------+-------+------+------+------+------+

The principal figures are those of all cases, fatal and non-fatal; the
small figures relate to fatal cases.

Transcriber’s Note: The ‘small figures’ are given here in brackets e.g.
(1.

[E] The principal numbers relate to cases, the small figures to deaths.
Fatal cases not reported in previous years are included as both cases and
deaths.

Transcriber’s Note: The ‘small figures’ are given here in brackets e.g.
(1.

[F] Fischer adopts a chemical basis in his classification. His two
main subdivisions are (1) inorganic and (2) organic poisons. The
sub-divisions of the inorganic poisons are (_a_) non-metallic—chlorine,
calcium chloride, hydrochloric acid, potassium chlorate, hydrofluoric
acid, carbonic oxide, phosgene, carbon dioxide, cyanogen compounds,
ammonia, nitrous fumes, phosphorus, phosphoretted hydrogen, arsenic
compounds, antimony compounds, sulphur dioxide, sulphuric acid,
sulphuretted hydrogen, carbon bisulphide, chloride of sulphur; and
(_b_) metallic—chromic acid and chromates, manganese dioxide, sulphate
of nickel, mercury and lead. The sub-divisions of (2) the organic
substances are into (_a_) the unsaturated carbon compounds—benzene,
petroleum, methyl-, ethyl-, amyl-, and allyl-alcohol, oxalic acid,
formal- and acetaldehyde, acrolein, acetone, methyl-bromide and
iodide, nitro-glycerin, dimethyl-sulphate and amyl acetate, and
(_b_) the aromatic series benzene, nitro-, chloro-nitro-, dinitro-,
chloro-dinitro-benzene, phenol, picric acid, phenyl-hydrazine, aniline,
and certain aniline colours, para-nitraniline, pyridine, naphthalene,
nitro-naphthalene, naphthlyamine, naphthol, benzidine, acridine,
turpentine, and nicotine.

[G] A Prussian Ministerial Decree, dated March 31, 1892, deals with the
preparation of nitrate of mercury.

[H] In Great Britain and Ireland the White Phosphorus Matches Prohibition
Act became operative from January 1, 1910. In the United States of
America a Prohibition Act became operative on July 1, 1913.

[I] Reprinted by permission of the Controller of H.M. Stationery Office.

[J] _Use of Oxygen Cylinder._—Open the valve gradually by tapping the
lever key (which must first be extended to its full length) with the
wrist, until the oxygen flows in a gentle stream from the mouthpiece into
the patient’s mouth. The lips should not be closed round the mouthpiece.
The nostrils should be closed during breathing in, and opened during
breathing out.

If the teeth are set, close the lips and one nostril. Let the conical end
of the mouthpiece slightly enter the other nostril during breathing in,
and remove it for breathing out.

[K] The suggested regulations made after his inquiry (see p. 149) by Dr.
Copeman are:

1. Ferro-silicon should not be sent out from the works immediately after
manufacture, but after being broken up into pieces of the size in which
it is usually sold, should be stored under cover, but exposed to the air
as completely as possible, for at least a month before being despatched
from the works.

2. Manufacturers should be required to mark in bold letters each barrel
or other parcel of ferro-silicon with the name and percentage grade
(certified by chemical analysis) of the material; the name of the works
where it is produced; the date of manufacture; and date of despatch.

3. The carriage of ferro-silicon on vessels carrying passengers should
be prohibited. When carried on cargo boats it should, if circumstances
permit, be stored on deck. If it be considered necessary to store it
elsewhere, the place of storage should be capable of being adequately
ventilated, and such place of storage should be cut off by airtight
bulkheads from the quarters occupied by the crew of the vessel.

4. This regulation should apply to the transport of ferro-silicon on
river or canal barges as well as on sea-going vessels.

5. Storage places at docks or at works where ferro-silicon is used should
have provision for free access of air, and should be situated at a
distance from work-rooms, mess-rooms, offices, &c.

[L] Regulations 5-7 contain precautions to be observed in the corroding
chambers.




APPENDIX

REFERENCES




PART I

PROCESSES OF MANUFACTURE AND INSTANCES OF POISONING


GENERAL SURVEY OF POISONING IN CHEMICAL INDUSTRIES

[1] Leymann, _Concordia_, 1906, Nos. 7, 8 and 9; [2] Grandhomme, _Die
Fabriken der Farbwerke zu Höchst a. M._, Verlag Mahlau, 4th edition.


SULPHURIC ACID INDUSTRY

[1] _Zeitschr. für. Gewerbe-Hygiene_, 1907, p. 230; [2] Bath, _Zeitschr.
f. Angew. Chemie_, 1896, p. 477.


HYDROCHLORIC ACID AND SALTCAKE MANUFACTURE

[1] _Zeitschr. f. Gewerbe-Hygiene_, 1906, p. 562; [2] _Zeitschr. f.
Gew.-Hyg._ 1902, p. 62; [3] Walther in Weyl’s _Arbeiterkrank-keiten_, p.
666.


CHLORINE AND BLEACHING POWDER

[1] _Zeitschr. für. Gew.-Hyg._, 1906, p. 280; [2] _Concordia_, 1906,
No. 8; [3] _Arch. f. Hyg._, vol. 46, p. 322; [4] Egli, _Unf. b. Chem.
Arb._, Zurich, 1902, p. 40; [5] Vaubel, _Chemiker Zeitung_, 1903; [6]
_Concordia_, 1907, No. 7; [7] Rumpf, _D. Med. Wochenschr._, 1908, vol.
34, p. 1331; [8] Müller, _Vierteljahrsschr. f. Ger. Med. ü öffentl.
Sanitätsw._, vol. ix., p. 381; and Roth, _Komp. d. Gewerbekrankh_, p.
205; [9] Klocke-Bochum, _Zeitschr. f. Gew.-Hyg._, 1906, p. 563; [10]
Sury Bienz, _Vierteljahrsschr. f. Ger. Med._, 1907, vol. 34, p. 251;
[11] Erben, _Handb. d. ärztl. Sachverst_, 1910, vol. ii. p. 266; [12]
_Concordia_, 1902, No. 5., and _Vierteljahrsschr. f. öff. Ges. Pfl._,
1902, Suppl. p. 371; [13] Mohr, _D. Med. Wochenschr_., 1902, vol. 28, p.
73; [14] ‘Über Chlorakne,’ _Archiv. f. Dermatol._, 1905, vol. 77, p. 323;
[15] Dammer, _Handb. d. Arb. Wohlf._, vol. i. p. 433; [16] _D. Arch. f.
Klin. Med._, 1901, vol. 71, p. 370; [17] Schuler, _D. Vierteljahrsschr.
f. öffentl. Ges. Pfl._, vol. 31, p. 696; [18] Egli, _Unf. b. Chem. Arb._,
Zurich, 1902, pp. 22, 45; [19] Rambousek, _Concordia_, 1910, No. 6.


MANUFACTURE AND USE OF NITRIC ACID AND ITS COMPOUNDS

[1] Schmitz, _Berl. Klin. Wochenschr._, 1884, vol. 21, p. 428, and
Becker, _Aerztl. Sachv. Ztg._, 1899, vol. v. p. 277; [2] _Concordia_,
1908, No. 23, p. 498; [3] Schmieden, _Zentralbl. f. Klin. Med._, 1892,
No. 11; Kockel, _Vierteljahrsschr. f. Ger. Med._, 1898, vol. 15; [4]
Egli, _Unf. b. chem. arb._, 1903, p. 52; [5] _Chem. Industrie_, 1905, p.
444; [6] _Chem. Industrie_, 1905, p. 445; [7] _Berl. Klin. Wochenschr._,
1886, vol. 23, p. 417; [8] _Komp. d. Gewerbekrankheiten_, p. 62; [9]
_Intern. Uebers. über Gew.-Hyg._, 1907, p. 76.


PHOSPHORUS AND LUCIFER MATCH MANUFACTURE

[1] _Die Phosphornekrose, ihre Verbreitung in Oesterreich_, Wien, 1907;
[2] Friedrichs, in _Arb. d. Ung. Ver. f. ges. Arbeiterschutz_ 1908,
vol. 4, pp. 1-176; [3] v. Jaksch, _Handb. d. ärztl. Sachv.-Tät._, 1909,
vol. 7, p. 239; and Lévai, _W. Klin. Rundsch._, 1900, vol. 14, p. 33,
and Dearden, _Brit. Med. Journ._, 1899, vol. 1, p. 92; [4] Wodtke,
_Vierteljahrsschr. f. ger. Med. und öffentl. Sanitätsw._, vol. 18, p. 325.


CHROMIUM COMPOUNDS

[1] Hermanni, _Münch med. Wochenschr._, 1901, No. 14, and Wodtke, _loc.
cit._, p. 325; [2] _Zeitschr. f. Gew.-Hyg._, 1908, p. 161; [3] Wutzdorff
und Heise, _Arb. a. d. Kais. Ges. Amt._, vol. xiii.; [4] _Zeitschr. f.
öffentl. Ges. Pfl._, 1894; [5] Burns, _Ann. Rept. of C. I. of F._, 1903;
[6] Neisser, _Intern. Uebers. über Gew.-Hyg._, 1907, p. 92.


MANGANESE COMPOUNDS

[1] Couper, _Journ. de Chimie_, vol. 3, series ii.; [2] _Münch. med.
Wochenschr._, 1901, p. 412; [3] Embden, _D. med. Wochenschr._, vol. 27,
p. 795.


PETROLEUM AND BENZINE INDUSTRY

[1] Berthenson, _D. Vierteljahrsschr. f. öffentl. ges.-Pfl._, 1898, vol.
30, p. 315; [2] _Virchow’s Archiv_, vol. 112, p. 35; [3] Felix, _D.
Vierteljahrsschr. f. öffentl. ges.-Pfl._, 1872; [4] _Lancet_, 1886, p.
149; [5] _Ramazzini_, 1908, vol. 2, p. 226; [6] Dorendorf, _Zeitschr.
f. Klin. Med._, 1901, p. 42; [7] _Brit. Med. Journ._, 1903, p. 546, and
_ibid._, 1908, p. 807; [8] _Zeitschr. f. Gew.-Hyg._, 1907, p. 157; [9]
Wichern, _Zeitschr. f. Gew.-Hyg._, 1909, Nos. 3 and 4; [10] Mitchell,
_Med. News_, iii., p. 152; _Ann. d’Hyg. publ._, vol. 24, p. 500; Arlidge,
_Dis. of Occupation_; _Revue d’Hygiène_, 1895, p. 166; Neisser, _Intern.
Uebers. f. Gew.-Hyg._, 1907, p. 96.


SULPHURETTED HYDROGEN GAS

[1] _Chem. Ind._, 1908, p. 323; [2] Pfeiler, _D. Vierteljahrsschr. f.
öffentl. Ges.-Pfl._, 1904; [3] _Lehre v. d. schädl. u. gift. Gasen_, p. 274.


CARBON BISULPHIDE

[1] _Archiv f. Hyg._, vol. 15, pp. 125-141; [2] Santesson, _Archiv f.
Hyg._, vol. 31, p. 336; [3] _Chem. Ind._, 1905, p. 442; [4] _Zeitschr.
f. Gew.-Hyg._, 1908 and 1909; [5] _Arch. f. Hyg._, xx., p. 74; [6] _Die
Schwefelkohlenstoffvergiftung der Gumniarbeiter_, Leipzig, Veit & Comp.,
1899; [7] _Ann. d’Hyg. publ._, 1863.


ILLUMINATING GAS

[1] _Krankheiten des Arbeiter_, 1871; [2] _Gewerbepathologie_, 1877;
[3] _Weyl’s Handb. d’Hyg._, 1894, vol. 8; [4] Sprenger and Albrecht:
Albrecht’s _Gewerbehygiene_, 1896; [5] Jehle, ‘Hygiene der Gasarbeiter,’
_Zeitschr. f. Gew.-Hyg._, 1901, pp. 245 and 261; [6] Schütte:
‘Krankheiten der Gasarbeiter,’ Weyl’s _Arbeiterkrankheiten_, 1908, p.
239; [7] Heymann’s Verlag, 1910; [8] _Zeitschr. f. Gew.-Hyg._, 1909, No.
12; [9] _Chem. Ind._, 1905, p. 442; [10] Egli, _Über d. Unf. b. Chem.
Arb._, Zurich, 1903; [11] _Gewerb. techn. Ratgeber_, 1906, p. 96.


COKE OVENS

[1] Hesse, _Concordia_, 1909.


POWER GAS, SUCTION GAS, &C.

[1] _Zeitschr. f. Gew.-Hyg._, 1906, p. 250; 1909, p. 297; 1906, p.
19; [2] _Gewerbl. techn. Ratgeber_, 1906, p. 297; [3] Nottebohm,
_Socialtechnik_, 1907, vol. 7, p. 80; [4] Finkelstein, _Jahr. d. Peych._,
1897, vol. 15, p. 116; [5] Jokote, _Arch. f. Hyg._, 1904, vol. 49, p. 275.


AMMONIA

[1] _Ber. pr. Gew. Insp._, 1904; [2] Egli, _loc. cit._, No. 2, p. 48;
[3] _Lehre v. d. schädl. u. gift. Gasen_, p. 274; [4] _Zeitschr. f.
gew.-Hyg._, 1909, p. 242; [5] _Berl. Klin. Wochenschr._, 1908.


CYANOGEN COMPOUNDS

[1] _Handb. d. Hyg._, vol. 8, p. 897; [2] Merzbach, _Hyg. Rundsch._,
1899, No. 1; [3] _Zeitschr. f. Med. Beamte_, 1907, vol. 20, p. 825; [4]
Kockel, _Vierteljahrsschr. f. ger. Med._, 1903, vol. 26; [5] Erben,
_Vergiftungen_, ii. p. 204.


TAR AND ITS DERIVATIVES

[1] Lewin, _Münchn. med. Wochenschr._, 1907; [2] Santesson, _Skand. Arch.
f. Physiol._, 1900, vol. 10, pp. 1-36; [3] _Concordia_, 1901, p. 287
Jahresber. d. Staatl. Aufsichtsbeamten über Unfallverbütung, 1909; [4]
Arb. d. Hamb. Gewerbeinspektoren, 1909; [5] Greiff, _Vierteljahrsschr. f.
ger. Med._, 1890.


COAL TAR COLOURS

[1] _Die Fabriken der Farbwerke vorm. Meister Lucius & Brüning zu Höchst
a. M._, 1896; [2] _Concordia_, 1910, p. 355; [3] _Vierteljahrsschr.
f. öffentl. Ges.-Pfl._, Supplem. pro 1902, p. 371; [4] Schröder,
_Vierteljahrsschr. f. ger. Med._, 1903, p. 138; Rump, _Zeitschr. f.
Med. Beamte_, 1903, p. 57; [5] Brat, _D. med. Wochenschr._, 1901, Nos.
19 and 20; [6] Mohr, _D. med. Wochenschr._, 1902; [7] _Zeitschr. f.
Gew.-Hyg._, 1908, p. 383; [8] Hanke, _W. Klin. Wochenschr._, 1899, vol.
12, p. 725; Frank, _Beiträge zur Angenheilk._, 1898, vol. 31, p. 93;
Silex, _Zeitschr. f. Angenheilk._, 1902, p. 178; [9] Dearden, _Brit. Med.
Journ._, 1902, vol. 2, p. 750; [10] _Ann. Rept. of C. I. of F._, 1905, p.
165; [11] _Münch, med. Wochenschr._, 1907; [12] Erdmann, _Arch. f. exp.
Path._, 1905, vol. 53, p. 401.


FERRO-SILICON

_Nature, Uses and Manufacture of Ferro-silicon_, by S. M. Copeman, S. R.
Bennett, and H. W. Hake. London. 1909. Cd. 4958.


LEAD AND ITS COMPOUNDS

Legge and Goadby, _Lead Poisoning and Lead Absorption._ Edward Arnold.
1912.

[1] Wächter, _Die gewerbliche Bleivergiftung im Deutschen Reich_, 1908,
p. 36; [2] _XIV. Intern. Kongr. f. Hyg. und Dem._, 1907, vol. 2, p.
746; [3] Rambousek, _Concordia_, 1910; [4] Müller, _Die Bekämpfung
der Bleigefahr in Bleihütten_, Fischer, 1908, 156; [5] Frey, _Die
Zinkgewinning und ihre Hygiene_, Hirschwald, Berlin, 1907; [6] Wächter,
_Die gew. Bleivergiftung_, 1908, Braun, Karlsruhe; [7] Clayton, _Brit.
Med. Journ._, 1906, vol. 1, p. 310; [8] _Bericht an die Intern.
Vereinigung für Arbeiterschutz_, 1908.


MERCURY AND ITS COMPOUNDS

[1] Laureck, _Weyl’s Arbeiterkr._, p. 62; [2] Giglioli, Ramazzini, 1909,
vol. 3, p. 230.


ARSENIC AND ITS COMPOUNDS

[1] _Zeitschr. f. Gew.-Hyg._, 1902, p. 441; [2] Prölss, _Friedreich’s Bl.
f. ger. Med._, 1901, p. 176.


ANTIMONY

[1] _Vergiftungen_, vol. ii. p. 285.


BRASS

[1] _Vierteljahrsschr. f. ger. Med._, 1906, p. 185; [2] _Arch. f. Hyg._,
1910, vol. 72, p. 358.




PART II

PATHOLOGY AND TREATMENT


OXYGEN INHALATION IN INDUSTRIAL POISONING

Brat, ‘Bedeutung der Sauerstofftherapie in der Gewerbehygiene, _XIV.
Intern. Kongr. f. Hyg. u. Dem._ und _Zeitschr. f. Gew.-Hyg._ 1908, Heft
13, S. 305; Dräger, ‘Zur Physiologie des Rettungsapparates mit komprim.
Sauerstoff, _I. Intern. Kongr. f. Rett.-Wes., Frankfurt a. M._ 1908,
und _Fabrikfeuerwehr_ 1908, Heft 19, S. 74; Klocke, ‘Die Bedeutung
der Sauerstoffinhalationen in der Gewerbehygiene,’ _Zeitschr. f.
Gew.-Hyg._ 1906, Heft 20, S. 559; Dräger, ‘Neue Untersuchungen über die
Erfordernisse eines zur Arbeit brauchbaren Rettungsapparates,’ _Zeitschr.
f. Gew.-Hyg._ 1905, S. 49; Klocke, ‘Sauerstoffrettungsapparate,’ _Soz.
Techn._ 1908, Nr. 14, S. 272.


HYDROFLUORIC ACID POISONING

Egli, _Unf. b. chem. Arb._, I, S. 23, und II, S. 45; Rambousek,
‘Gewerbekrankh. in Böhmen,’ _Concordia_ 1910, Heft 6, und _Amtsarzt_
1910, Heft 7.


SULPHURIC ACID AND SULPHUR DIOXIDE

Ogata, _Arch. f. Hyg._, Bd. 2; Lehmann, _Arch. f. Hyg._, Bd. 18, S. 180
ff; Klocke ‘(SO₂-Vergiftung und O-Inhal.),’ _Zeitschr. f. Gew.-Hyg._
1906, S. 562 und 617; ‘SO₂-Absorption beim Atemprozess,’ Chem. Ztg.
1909, S. 246; ‘Tod durch Einatmung von Schwefelsäuredampf,’ _Zeitschr.
f. Gew.-Hyg._ 1907, S. 430; ‘Schwefel-dioxydvergiftung in England,’
_Concordia_ 1909, Heft 5, S. 105; ‘Schwefels.-Vergiftung, _Chem. Ind._
1909 _(Ber. d. Berufsgen. f. chem. Ind. pro_ 1908, S. 26); Egli, _Unf. b.
chem. Arb._, ii, S. 52.


NITRIC ACID AND NITROUS FUMES

‘Verg. durch nitrose Gase in einer Zellulosefabrik,’ _Zeitschr. f.
Gew.-Hyg._ 1908 Heft 24, S. 565; ‘Behandlung von Nitrosevergiftungen
durch Sauerstoffinhalationen,’ _Zeitschr. f. Gew.-Hyg._ 1908, Heft 20, S.
560; ‘Behandlung durch Chloroform,’ _Zeitschr. f. Gew.-Hyg._ 1904, Heft
10, S. 226, und 1907, Heft 8, S. 183; ‘Vergiftungen durch nitrose Gase
(Zusammenfassung),’ Holtzmann, _Concordia_, 1908, Nr. 23, S. 498.


CHLORINE, BROMINE, AND IODINE

Leymann, _Arch. f. Hyg._, Bd. 7, S. 231; Binz, _Arch. f. exp. Path._,
Bd. 13; _Vierteljahrsschr. f. ger. Med._ 1888, S. 345; Lehmann, _Arch.
f. Hyg._, Bd. 34, S. 302, und _Arch. f. Hyg._, Bd. 17, S. 336; _Arch. f.
exp. Path. u. Ph._ 1887, S. 231; Egli, _Unf. b. chem. Arb._, II, S. 51;
Chlorverg., _Chem. Ind._ 1907, S. 347, 1908, S. 325; Neisser, _Intern.
Uebers. über Gew.-Hyg._, I, S. 94; ‘Chlorverg. in England,’ _Concordia_
1909, S. 105.

_Literatur Über Chlorakne._—Herxheimer, _Münchn. med. Wochenschr._ 1899
S. 278; Bettmann, _D. med. Wochenschr._ 1901, S. 437; Lehmann, _Arch.
f. Dermatol._ 1905, S. 323; Leymann, ‘Erk.-Verh. der chem. Grossind.,’
_Concordia_ 1906, Nr. 7-9; Holtzmann, _D. Vierteljahrsschr. f. öffentl.
Ges.-Pfl._ 1907, Bd. 39, S. 258.


CHLORIDES OF PHOSPHORUS

Vaubel, _Chem. Ztg._ 1903; Leymann, _Concordia_ 1906, Nr. 7; Egli, _Unf.
b. chem.-Arb._ 1902, S. 49; Rumpf, _D. med. Wochenschr._ 1908, Bd. 34, S.
1331.


CHLORIDE OF SULPHUR

Lehmann, _Arch. f. Hyg._ 1894, Bd. 20, S. 26; Leymann, _Concordia_ 1906,
Heft 7.


AMMONIA

Lehmann, ‘Verauche über die Wirkung,’ _Arch. f. Hyg._, Bd. 5; ‘Vers.
über die Resorption,’ _Arch. f. Hyg._, Bd. 17 u. 67; ‘Versuche über die
Gewöhnung,’ _Arch. f. Hyg._, Bd. 34; Lewin, ‘Tödl. Ammoniakverg. in
einer chem. Fabrik, Berl. klin. Wochenschr. 1908; ‘Tödl. Ammoniakverg.,’
_Zeitschr. f. Gew.-Hyg._ 1909, Wr. 9, S. 242; ‘Ammoniakverg. in der
Kälte-Ind.’


LEAD POISONING

‘Vorkommen der Bleivergiftung. Bleierkrankungen in der Bleihütte
Braubach,’ _Zeitschr. f. Gew.-Hyg._ 1909, S. 291; _Bleivergiftungen
in gewerbl. u hüttenmänn. Betrieben_ (_Oesterreichs_), herausgegeben
vom k. k. Arbeitsstat. Amt: I. Erhebungen in Blei- und Zinkhütten;
II. Erhebungen in Bleiweiss- und Bleioxydfabriken; III. Expertise,
betreffend die Blei- und Zinkhütten; IV. Expertise, betreffend die
Bleiweiss- und Bleioxydfabriken; V. Erhebungen in Farbenfabriken und
Betrieben mit Anstreicher-, Lackierer- und Malerarbeiten; VI. Expertise
hierzu; VII. Erhebungen und Expertise in Buch- und Steindruckereien
und Schriftgisseereien (alle Teile erschienen bei Alfr. Hölder, Wien
1905-1909). Frey, _Zinkgewinnung im oberschles. Industriebezirk_,
Berlin 1907, Verlag Hirschwald; Leymann, _Die Bekämpfung der Bleigefahr
in der Industrie_, Verlag Fischer, Jena 1908; Müller, _Die Bekämpfung
der Bleigefahr in Bleihütten_, Verlag Fischer, Jena 1908; Wächter,
_Die gewerbl. Bleiverg. im Deutschen Reich_, Verlag Braun, Karlsruhe
1908; Chyzer, _Les intoxications par le plomb se présentant dans la
céramiquen en Hongrie_, Schmidl, Budapest 1908; Kaup, _Bleiverg. in der
keramischen Ind._, als Manuskript gedruckt, D. Sekt. Ges. f. Soziale
Reform; Teleky, ‘Beitrag z. H. d. Erzeug. v. ord. Töpferware usw. in
Oesterr.,’ _Arbeiterschutz_, 1908, Nr. 19, 20; De Vooys, _Bleiverg. in
der niederl. keram. Ind._ (Nederl. Vereen. voor wettelijke Beseherming
van arbeiders 1908); Kaup, _Bleiverg. in österr. Gew.-Betrieben_,
Schriften des österr. Vereines für Arbeiterschutz 1902, Heft 3;
Sommerfeld, ‘Zur Bleiweissfrage,’ _Soz. Praxis_ 1902, Nr. 8; Friedinger,
‘Sanit. Verh. in d. Buchdr.,’ _Soz. Praxis_ 1902, Nr. 9; Wutzdorff,
_Bleiverg. in Zinkhütten_, Arb. a. d. Kais. Ges.-Amte, Bd. 17, S. 441;
Blum, _Unters. über Bleiverg._, Frankfurt a.M. 1900, _Vierteljahrsschr.
f. öffentl. Ges.-Pfl._, Suppl. 32, S. 630; Panwitz, _Bleiverg. in
Buchdruckereien_, Veröff. d. Kais. Ges.-Amtes 1897, S. 503; Teleky,
‘Bleiverg. bei Fransenknüpferinnen,’ Ref. _Zeitschr. f. Gew.-Hyg._ 1907,
Nr. 1, S. 13; ’ Bleierkrankung und Bekämpfung ders., Literatursammlung,’
_Zeitschr. f. Gew.-Hyg._ 1904, Nr. 6, S. 131; Teleky, ‘Die gewerbl.
Bleiverg. in Oesterreich,’ _Soz. Techn._ 1909, Nr. 17, S. 333; Bleiverg.
(Legge), Verh. d. II. Intern. Kongr. f. Gewerbekrankh. in Brüssel 1910;
Bleiverg. in Böhmen (Rambousek), Concordia 1910, Nr. 7, Amtsarzt 1910,
Nr. 6; Abelsdorff, Statistik d. Bleiverg., Concordia 1910, Heft 17, S.
359; Wutzdorff, ‘Bleiverg. in Akkumulatoreniabr.,’ _Arb. a. d. Kais.
Ges.-Amte_ 1898, Bd. 15, S. 154; Rasch, ‘Ueber Bleiverg. d. Arb. in
Kachelfabr.,’ _Arb. a. d. kais. Ges.-Amte_ 1898, Bd. 14, S. 81.


GENERAL LITERATURE ON PATHOLOGY AND TREATMENT OF LEAD POISONING

Jores, ‘Die allg. pathol. Anatomie der chron. Bleiverg. des Kaninchens,’
_Beiträge z. path. Anat. u. allg. Path._ 1902, Bd. 31, S. 183; Glibert,
_Le saturnisme experimental, extrait d. rapp. ann. de l’insp. du travail
en 1906_, Bruxelles, 1907. Rambousek, ‘Die Pathol. d. Bleiverg.’ in
Leymann’s _Bekämpfung d. Bleigef._, S. 15, Velag Fischer, Jena 1908;
_Die Verhütung d. Bleigefahr_, Verlag Hartleben 1908; Blum, ‘Unters.
über Bleiverg., Frankfurt a.M. 1900,’ _Vierteljahrsschr. f. öffentl
Ges.-Pfl._, Suppl. 32, S. 630; Elschnig, ‘Sehstörungen b. Bleiverg.,’
Ges. d. Aerzte, Wien, Sitzung v. 15. April 1898, und _Wiener med.
Wochenschr._ 1898, S. 1305; ‘Neuere Forschungen über Bleiverg.,’
_Zeitschr. f. Gew.-Hyg._ 1909, S. 629; Seeligmüller, ‘Einfl. d. Bleies
auf den Frauenorganismus usw.,’ _Berl. klin. Wochenschr._ 1901, S. 842;
Bernhardt, ‘Zur Pathol. d. Bleilähmung,’ _Berl. klin. Wochenschr._
1900, S. 26; Rambousek, ‘Die Bleierkrankung,’ _Zeitschr. f. ärztl.
Fortbildung_ 1909, Nr. 7; Israel, ‘Obd.-Befund b. Bleiverg.,’ _Berl.
klin. Wochenschr._ 1895, S. 575; Gumpertz, Bernhardt, ‘Anom. d. elektr.
Erregb. b. Bleiverg.,’ _Berl. klin. Wochenschr._ 1894, S. 372 u. S.
284; Jolly, ‘Sekt.-Befund b. Bleilänmung, Entart. d. Gangl.,’ _Berl.
klin. Wochenschr._ 1893; Miura, ‘Ueber die Bedeutung des Bleinachweises
auf der Haut Bleikranker,’ _Berl. klin. Wochenschr._ 1890, S. 1005;
Mattirolo, ‘Behandlung d. Bleikolik mit Erythroltetranitrat,’ _Wiener
med. Presse_ 1901, _Wiener med. Wochenschr._ 1901, S. 2171; Oddo und
Silbert, ‘Ausscheidung des Bleis,’ _Revue med._ 1892, Nr. 4, und _Wiener
med. Presse_ 1892, S. 1182; Mosse, ‘Veränderungen d. Gangl. coeliac. bei
exper. Bleikolik,’ _Wiener klin. Wochenschr._ 1904, S. 935; Escherich,
‘Zwei Fälle v. Bleilähmung b. Kindern (Peroneuslähmung.),’ _Wiener klin.
Wochenschr._ 1903, S. 229; Variot, ‘Ein Fall v. Bleilähmung b. einem
Kinde (Peroneuslähmung),’ _Gaz. des Hôp._ 1902, S. 482, und _Wiener klin.
Wochenschr._ 1902; Sorgo, ‘Progress. Muskelatrophie nach Bleiverg.,’
_Weiner med. Wochenschr._ 1902, S. 919; Variot, ‘Bleiverg. b. einem
Kinde, Parese d. unt. Extrem.,’ _Wiener med. Wochenschr._ 1902, S. 2056;
Rome, ‘Bleiverg. b. Kindern,’ _La trib. med._ 1902, Nr. 39, und _Wiener
med. Wochenschr._ 1902, S. 2391; Layal, Laurencon, Rousel, ‘Erscheinungen
der Pylorusstenose b. Bleiverg.,’ _Wiener med. Wochenschr._ 1897;
Macfairlain, ‘Chloroformbehandlung bei Bleikolik,’ _Wiener med.
Wochenschr._ 1895; Bechtold, ‘Spast. Spinalparalyse b. Bleiverg.,’ _Med.
chir. Zentralbl._ 1904, Nr. 40; Oliver, ‘Lead-poisoning, &c.,’ _Lancet_,
1891, S. 530; Heymann, ‘Lähmungen d. Kehlkopfmuskeln b. Bleiverg.,’
_Arch. f. Laringol._ 1896, S. 256; Clayton, ‘Ind. lead-poisoning,’
_Brit. med. journ._ 1906, S. 310; Taylor, ‘Bleiamblyopie,’ _Lancet_
1898, S. 742; Seeligmüller, ‘Zur Pathol. d. chron. Bleiverg.,’ _D.
med. Wochenschr._ 1902, S. 317; Lewin, ‘Puls b. Bleiverg.,’ _D. med.
Wochenschr._ 1897, S. 177; Walko, ‘Erkr. d. Magens b. chron. Bleiverg.,’
_Münchn. med. Wochenschr._ 1907, S. 1728; Tielemanns, _Parotiserkr.
b. Bleiverg._, Monogr., Paris 1895; Borgen, ‘Blutdruckbestimmungen b.
Bleikolik,’ _D. Arch. f. klin. Med._ 1895, S. 248; Klieneberger, ‘Intox.
saturn. und Nephritis sat.,’ _München. med. Wochenschr._ 1904, S. 340;
Bach, ‘Augenerkr. b. Bleiverg.,’ _Arch. f. Augenheilk._ 1893, S. 218;
Redlich, ‘Tabes und chron. Bleiverg.,’ _Wiener med. Wochenschr._ 1897,
S. 801; Seifert, ‘Kehlkopfmuskellähmung b. Bleiverg.,’ _Berl. klin.
Wochenschr._ 1884, S. 555.


LITERATURE ON BLOOD CHANGES IN LEAD POISONING

Schmidt, ‘Die Bleiverg. und ihre Erkennung,’ _Arch. f. Hyg._ 1907, Bd.
63, Heft 1; Galperin-Teytelmann, _Die basophilen Granula der roten Blutk.
b. Bleairbeitern, Ing. Diss._, Bonn 1908; Carozzi, _Reperti ematol. e
loro valore statistico nel saturn. prof. Corr. sanitar._ 1909, Bd. 20,
Nr. 5 u. 6; Gilbert, _Le saturnisme exp._, Bruxelles, 1907; Rambousek,
‘Beitrag z. Pathol. d. Stoffw. und d. Blutes b. Bleiverg., _Zeitschr. f.
exp. Path. und Therap._ 1910, Bd. 7; Moritz, ‘Beziehungen der basophilen
Granula zu den Erythrozyten,’ _Münchn. med. Wochenschr._ 1901, Nr. 5;
_St. Petersburger med. Wochenschr._ 1901, Nr. 26, 1903, Nr. 50; _Verh. d.
I. Intern. Kongr. f. Arb.-Krankh. in Mailand_ 1906, _Atti del congresso_,
S. 601-607; Trautmann, ‘Blutunters. b. Bleiverg.,’ _Münchn. med.
Wochenschr._ 1909, S. 1371; Grawitz,’Ueber die körn. Degenerat. d. roten
Blutkörperchen,’ _D. med. Wochenschr._ 1899, Nr. 44; ‘Die klin. Bedeutung
und exp. Erzeugung körn. Degener. in den roten Blutkörperchen,’ _Berl.
klin. Wochenschr._ 1900, Nr. 9; Hamel, ‘Ueber die Beziehungen der körn.
Degener. der roten Blutkörperchen zu den sonst. morph. Veränd. des Blutes
mit besonderer Berücks. d. Bleiintox.,’ _D. Arch. f. klin. Med._ 1900,
Bd. 67; Frey, ‘Beitrag zur Frühdiagnose v. chron. Bleiverg.,’ _D. med.
Wochenschr._ 1907, Nr. 6; Grawitz, _Klin. Pathol. des Blutes_, Leipzig
1906, S. 120 ff.; Naegeli, ‘Ueber die Entstehung der basoph. gek. roten
Blutk.,’ _München. med. Wochenschr._ 1904, Nr. 5; Schmidt, ‘Zur Frage
d. Entstehung d. basoph. Körner,’ _D. med. Wochenschr._ 1902, Nr. 44;
_Exp. Beiträge z. Pathol. d. Blutes_, Jena 1902; ‘Ein Beitrag. z. Frage
d. Blutregen.,’ _Münchn. med. Wochenschr._ 1903, Nr. 13; Erben, ‘Chem.
Zusammensetzung d. Blutes b. Bleiverg.,’ _Zeitschr. f. Heilkunde_, 1905,
S. 477.


LITERATURE ON CHANGES IN METABOLISM IN LEAD POISONING

Preti, ‘Beitrag z. Kenntn. d. Stickstoffums. b. Bleiverg.,’ 1909,
S. 411; Rambousek, ‘Beitrag z. Pathol. d. Stoffw. und d. Blutes,’
_Zeitschr. f. exp. Path. und Ther._ 1910, Bd. 7; ‘Pathol. d. Bleiverg.’
in Leymann’s _Bekämpfung d. Bleigefahr_, Fischer, Jena 1909; Minkowski,
_Die Gicht_, Wien, 1903, Holders Verlag.; Schittenhelm und Brugsch, ‘Zur
Stoffwechselpathol. d. Gicht,’ _Zeitschr. f. exp. Path. und Ther._, Bd.
4, S. 494-495.


LITERATURE ON TOXICITY OF VARIOUS LEAD COMPOUNDS

Blum, ‘Unters. über Bleiverg., Frankfurt a. M. 1900,’ _Vierteljahrsschr.
f. öffentl. Ges.-Pfl._, Suppl. 32, S. 630; Rambousek, _Die Verhütung der
Bleigefahr_, Verlag Hartleben 1908; Biondi und Rambousek, ‘Polemik über
die Ungiftigkeit d. Bleisulfids,’ _I. Intern. Kongr. f. Gew.-Krankh. in
Mailand_ 1906, _Atti del congresso_, S. 617-622; Lehmann, ‘Hyg. Unters.
über Bleichromat,’ _Arch. f. Hyg._ 1893, Bd. 16, S. 315.


ZINC

Schlockow, ‘Ueber ein eigenartiges Rückenmarksleiden bei
Zinkhüttenarbeitern,’ _D. med. Wochenschr._ 1879, S. 208; Tracinsky, ‘Die
oberschlesische Zinkindustrie usw.,’ _D. Vierteljahrsschr. f. öffentl.
Ges.-Pfl._ 1888, Bd. 20, S. 59; Seiffert, ‘Erkr. d. Zinkhüttenarb. usw.,’
_ibidem_ 1897, Bd. 31, S. 419; Lehmann, ‘Beiträge z. hygien. Bedeutung
d. Zinks,’ _Arch. f. Hyg._ 1897, Bd. 28, S. 300; Neuere Arbeiten: Frey,
_Die Zinkgew. im oberschl. Industriebez.-usw._,’ Verlag Hirschwald-Berlin
1907 und _Zeitschr. f. Gew.-Hyg._ 1907, Nr. 16, S. 376; Sigel, ‘Das
Giesserfieber u. seine Bekämpfung,’ _Vierteljahrsschr. f. ger. Med._
1906, Bd. 32, S. 173; Lehmann, ‘Giess- oder Zinkfieber,’ _Arch. f. Hyg._
1910, Bd. 72, S. 358.


MERCURY

Schönlank, _Fürther Spiegelfabriken_ 1888 (Monogr.); Wollner,
‘Quecksilberspiegelfabrik in Fürth,’ _Vierteljahrsschr. f. öffentl.
Ges.-Pfl._, Bd. 19, 3, S. 421, und _Münchn. med. Wochenschr._ 1892, Bd.
39, S. 533; Stickler, ‘Hutfabrikation, 1886,’ _Revue d’Hygiène_, VIII, S.
632; Charpentier, ‘Spiegelfabrik,’ _Annal. d’hyg. publ._, avril 1885, S.
323; Henke, _Quecksilberverg. in Hutfabriken_, Knauer, Frankfurt 1889;
Wittzack, ‘Quecksilberverg. b. d. Spiegelbel. usw.,’ _Vierteljahrsschr.
f. öffentl. Ges.-Pfl._ 1896, S. 216; Donath, ‘Quecksilberverg. in
Gluhlampenfabriken,’ _Wiener med. Wochenschr._ 1894, 8. 888; Renk,
’ Quecksilberverarbeitung,’ Arb. a. d. Kais. Ges.-Amte, Bd. 5, Heft
I; Letulle, ‘Hasenhaarschneiderei,’ _Revue d’Hyg._, XI, S. 40; Ueber
Hasenfellbeize, _Zeitschr. f. Gew.-Hyg._ 1909, S. 821; _Sozialtechn._
1910, S. 39; ‘Quecksilberverg. in d. Glühlampenind.,’ _Zeitschr.
f. Gew.-Hyg._ 1908, S. 469; ‘Quecksilberverg. in Amiata in Italien
(ausführliche Schilderung der Symptome schwerer Quecksilberverg.),’
Giglioli, im _Ramazzini_ 1909, Bd. 3, S. 230, und ‘Demonstration am
II. Ital. Kongr. f. Arbeiterkrankh. in Florenz 1909,’ ref. _Zeitschr.
f. Gew.-Hyg._ 1909, S. 289, und _Chem. Ztg._, Repert., 1909, S. 411;
‘Quecksilberverg. in Hutfabriken in Italien,’ _Ramazzini_, 1909, S. 230;
Laureck, in Weyls _Handb. d. Arb.-Krankh._ 1909, S. 62.


MANGANESE

Couper, _Journ. de chim._, 1837, Bd. 3, S. 2; Jaksch, _Münchn. med.
Wochenschr._ 1901, S. 602; Embden, _D. med. Wochenschr._, Bd. 27,
S. 795, u. _Münchn. med. Wochenschr._ 1901, S. 1852; Jaksch, ‘Ueber
Manganintoxikationen u. Manganophobie,’ _Münchn. med. Wochenschr._ 1907,
Bd. 54, S. 969; Hauck, ‘Manganismus.’ Vortrag auf dem XIV. Intern. Kongr.
f. Hyg. u. Dem., Berlin 1907, Bd. 4, S. 337; Friedel, D. med. Wochenschr.
1909, S. 1292.


CHROMIUM

Delpech et Hillaret, _Annal. d’Hyg. publ._ 1876; Viron, _Contrib. à
l’étude phys. et tox. de quelques prép. chromés_, Paris, 1885; Burghardt,
‘Chromverg. in der Zündhölzchenindustrie,’ _Charité Annalen_, XXIII,
1898, S. 189; Wutzdorff, ‘Die in den Chromatfabriken beobachteten
Gesundheits-schädigungen.’


NICKEL

Nickelkrätze: ‘Jahresberichte d. preuss. Reg.- u. Gewerberäte für das
Jahr 1907,’ _Zeitschr. f. Gew.-Hyg._ 1908, Nr. 8, S. 185, u. 1909, Nr.
14, S. 374; Klocke, _Soz. Med. u. Hyg._ 1910, Bd. 5, Nr. 2.


NICKEL CARBONYL

H. W. Armit: _Journ. of Hygiene_, 1907, p. 524, and 1908, p. 565; Vahlen,
_Arch. exp. Pathol. u. Ph._ 1902, Bd. 48, S. 117; Mittasch, _Arch. f.
exp. Path._ 1903, Bd. 49, S. 367; Langlois, _Compt. rend. de la soc. de
Biol._ 1891, S. 212.


SILVER (ARGYRIA)

Schubert, ‘Argyrie bei Glasperlenversilberern,’ _Zeitschr. f. Heilk._
1895, Bd. 16, S. 341; Lewin, ‘Lokale Gewerbeargyrie,’ _Berl. klin.
Wochenschr._ 1886, S. 417; Blaschko, _Arch. f. mikr. Anatomie_, Bd. 27,
S. 651.


ARSENIC

‘Arsenverg. in der Delainage,’ _Zeitschr. f. Gew.-Hyg._ 1906, Nr. 3, S.
71; ‘Arsenikverg. in der Ind.,’ _Zeitschr. f. Gew.-Hyg._ 1907, S. 353,
und 1903, S. 476; ‘Arsenikverg. in England, nach den Ber. der engl.
Gew.-Insp.,’ _Concordia_ 1909, Nr. 5, S. 105; Egli, _Unf. b. chem. Arb._,
II, S. 51.


PHOSPHORUS

Lorinser, _Med. Jahrb. d. österr. Staates_, 1845, Bd. 51, S. 257; und
_Zeitschr. d. Gesellsch. d. Aerzte in Wien_, 1851, Bd. 55, S. 22;
Geist u. Bibra, _Die Krankh. d. Arb. in der Phosphorzündholzfabrik_,
Erlangen 1847; Wegner, _Virch.-Arch._ 1872, Bd. 55, S. 11; Magitot,
_Revue d’Hygiène_, 1895, Bd. 17, S. 201; Kollin, ‘Oberkiefernekrose,’
_Zentralbl. f. inn. Med._ 1889, S. 1279; Dearden, ‘Osseous fragilit. am.
workers in luc. match fet.,’ _Brit. Med. Journ._ 1899, S. 92; Lévai,
‘Ueber Phosphornekrose,’ _Wiener klin. Rundsch._ 1900, S. 33; ‘Ein Fall
von Phosphornekrose 19 Jahre nach der Arbeit in Zündhölzchenfabriken,’
_Wiener klin. Rundsch._ 1896, Nr. 29, S. 503; Stockman, _Brit. Med.
Journ._ 1899; Stubenrauch, _Arch. f. klin. Chir._ 1899, Heft 1, und
_Samml. klin. Vortr._ 1901, Nr. 303; Röpke, _Zeitschr. d. Zentralst.
f. Arb.-Wohlf.-Einr._ 1901, Nr. 1; ‘Phosphorverg. in England (nach den
Berichten der engl. Gew.-Insp.),’ _Concordia_, 1909, Nr. 5, S. 105;
Teleky, ‘Die Phosphornekrose in Oesterreich,’ _Schriften der Oesterr.
Gesellsch. f. Arbeiterschutz_, Heft 12, Verlag Deuticke 1907; Friedrich,
‘Die Phosphorverg. in Ungarn’ (in ungar. Sprache), _Schriften der Ungar.
Gesellsch. f. Arbeiterschutz_, Heft 4, Budapest 1908.


PHOSPHORETTED HYDROGEN

Schulz, _Arch. f. exp. Path. u. Phys._ 1890, Bd. 27, S. 314; Dietz,
‘Phosphorwasserstoffverg. bei einem Phosphorfabrikarb.,’ _Arch. f. Hyg._
1904, Bd. 49.

Spezielle Literatur über Phosphorwasserstoffvergiftung durch
Ferrosilizium: Bahr, Lehnkering, ‘Phosphorverg. durch Ferrosiliz.,’
_Vierteljahrsschr. f. ger. Med._ 1906, S. 123; _Jahresber. d. engl.
Gew.-Insp. f. d. J._ 1907 (vgl. _Soz. Techn._ 1908, Bd. 7, S. 689 und
690); Oliver, _Diseases of Occupation_, 1908; H. Le Chatelier, _Ann.
Min._ 1909, Bd. 15, S. 213; vgl. ferner _Zeitschr. f. Gew.-Hyg._ 1908, S.
574, und S. 181.


HYDROGEN SULPHIDE

Lehmann, ‘Exp. Studien über Schwefelw.,’ _Arch f. Hyg._, Bd. 14,
S. 142; ‘Gewöhnung an Schwefelw.,’ _ibidem_, Bd. 34, S. 303;
‘Absorption von Schwefelw.,’ _ibidem_, Bd. 17, S. 332; Blumenstock,
‘Lehre von der Verg. mit Kloakengasen,’ _Vierteljahrsschr. f. ger.
Med._ 1873, Bd. 18, S. 295; Kasper, ‘Massenverg. mit Kloakengas,’
_Vierteljahrsschr. f. ger. Med._, Bd. 2, S. 593; Römer, ‘Akute tödl.
Schwefelwasserstoffverg.,’ _Münchn. med. Wochenschr._ 1897, S. 851;
Oliver, dieselbe, _Lancet_, 1903, S. 225; ‘Schwefelwasserstoffverg.
bei der Saturation v. Schwefelbarium,’ _Ber. d. Berufsgen. f. Chem.
Ind._ 1907, _Chem. Ind._ 1908, S. 323; ‘Schwefelwasserstoffverg. in
einer Fabrik auf Ammoniaksalze’; Egli, _Unf. b. chem. Arb._, II, S. 46;
‘Schwefelwasserstoffverg. in England, Ber. d. engl. Gew.-Insp.,’ siehe
_Concordia_, 1909, S. 105; ‘Schwefelwasserstoffverg. in d. chem. Ind.,’
_Techn. gewerbl. Ratgeber_ 1906, S. 108; ‘Schwefelwasserstoffverg. und
Sauerstoffinhalation,’ _Zeitschr. f. Gew.-Hyg._ 1906, S. 587; ‘Erste
Hilfe bei Schwefelwasserstoffverg.,’ _Zeitschr. f. Gew.-Hyg._ 1908, S.
455, auch _Chem Ind._ 1908, S. 327.


CARBON BISULPHIDE

Delpech, ‘Accidents qui développent chez les ouvriers en caoutchouc et
du sulfure de carbone etc.,’ _L’Union méd._ 1876, No. 66; ‘Nouvelles
recherches sur l’intox. du _CS_₂ etc.,’ _Ann. d’Hyg. publ._ Nr. 37;
Sapelier, ‘Étude sur le sulfure de carbone,’ Thèse, Paris 1885;
Rosenblatt, _Ueber die Wirkung v. CS₂-Dämpfen auf den Menschen_, Diss.
Würzburg 1890; Pichler, _Ein Beitrag z. Kenntn. d. akuten CS₂-Verg._,
Berlin 1897 (Fischer); Lehmann, ‘Exp. Stud. über Schwefelk.,’ _Arch.
f. Hyg._ 1894, Bd. 20, S. 56 ff.; _Zeitschr. f. Gew.-Hyg._ 1899,
‘Schutzmassregeln der Kautschukindustrie in England’; Laudenheimer,
_Schwefelk.-Verg. d. Gummiarb._ 899, Leipzig, Veit & Comp.; Harmsen, ‘Die
Schwefelk. im Fabr. Betrieb,’ _Vierteljahrsschr. f. ger. Med._ 1905,
S. 149; Riegler, ‘Die nervösen Störungen bei CS₂-Verg.,’ _Zeitschr. f.
Nervenh._ 1907, Bd. 33; Roth, ‘Gewerbl. CS₂-Verg. usw.,’ _Berl. klin.
Wochenschr._ 1901, S. 570; Reiner, ‘Schwefelk.-Amblyopie,’ _Wiener klin
Wochenschr._ 1895, S. 919; Quensel, ‘Geistesstörungen nach CS₂-Verg.,’
_Monatsh. f. Psych._ 1905, Bd. 16.


CYANOGEN AND CYANOGEN COMPOUNDS (PRUSSIC ACID, &C.)

Merzbach, ‘Chron. Zyanverg. bei einem Galvaniseur,’ _Hyg. Rundsch._
1899, Nr. 1; Pfeiffer, ‘Zyanverg. d. Kanalgase (Abgänge v. d.
Zyangewinnung),’ _Vierteljahrsschr. f. öffentl. Ges.-Pfl._ 1904;
Stritt, ‘Verg. d. Zyanverb. im Düngemittel,’ _Zeitschr. f. Hyg._ 1909,
Bd. 62, S. 169; Tatham, ‘Zyanverg. beim Reinigen v. Goldspitzen,’
_Brit. Med. Journ._ 1884, S. 409; Kockel, ‘Blausäureverg. bei einem
Zelluloidbrand,’ _Vierteljahrsschr. f. ger. Med._ 1903, S. 1; ‘Zyanverg.
u. Sauerstoffinhal.’ (Brat), _Zeitschr. f. Gew.-Hyg._ 1906, S. 588;
Lehmann, ‘Ueber die Gift. d. gasförm. Blausäure (Giftigkeitsgrenzen),’
_Berl. klin. Wochenschr._ 1903, S. 918; Blaschko, ‘Berufsdermatosen d.
Arb. (Hautleiden b. Verwendung v. Zyaniden),’ _D. med. Wochenschr_, 1889,
S. 915; MacKelway s. (Hautleiden), _Amer. Journ. of Medic. Science_,
1905, S. 684; Wilkes (ditto), _Lancet_, 1904, S. 1058.


ARSENIURETTED HYDROGEN GAS

‘Arsenwasserstoffverg. (Verfertigen v. Kinderballons),’ _Zeitschr.
f. Gew.-Hyg._ 1902, S. 441; ‘Arsenwasserstoffverg. (Ausleeren eines
Schwefelsäuretanks),’ _Gewerbl. techn. Ratgeber_ 1906, S. 109;
‘Arsenwasserstoffverg. im Hüttenbetriebe (_O_-Inhalation),’ _Zeitschr. f.
Gew.-Hyg._ 1906, S. 589 u. S. 617; ‘Arsenwasserstoffverg.,’ _Zeitschr.
f. Gew.-Hyg._ 1908, S. 263, u. 1910, S. 179; ‘Arsenwasserstoffverg. in
England, nach den Ber. d. engl. Gew.-Insp.,’ _Concordia 1909_, S. 105;
Egli, ‘Arsenwasserstoffverg.,’ _Unf. b. chem. Arb._, II, S. 42; Lunge,
‘Arsenwasserstoffverg. beim Löten,’ _Chem.-Ztg._ 1904, S. 1169; Barié,
‘Arsenwasserstoffverg. durch Ballongas,’ _Arch. f. krim. Anthrop._ 1906,
S. 147.


CARBONIC OXIDE

_General Literature on CO-Poisoning._—Becker, ‘Die _CO_-Verg. u. ihre
Verhütung,’ _Vierteljahrsschr. f. ger. Med._ 1893, S. 349; Greiff,
‘_CO_-Verg. bei d. Teerdestill., _Vierteljahrsschr. f. ger._ Med. 1890,
S. 359; Brouardel, ‘_CO_-Verg. d. Kalkofengase,’ _Ann. d’Hyg. publ._
1840; Becker, ‘Nachkrankheiten d. _CO_-Verg.,’ _D. med. Wochenschr._
1893, S. 571; Reinhold, ‘Chron. _CO_-Verg.,’ _Münchn. med. Wochenschr._
1904, S. 793; ‘_CO_-Verg. beim Sengen des Garnes,’ _Zeitschr. f.
Gew.-Hyg._ 1909, S. 267.

_Literature on CO-Poisoning in Gas Works._—Jehle, ‘Hyg. d. Gasarbeiter,’
_Zeitschr. f. Gew.-Hyg._ 1901, Heft 14 u. 15, S. 245 ff.; Schütte,
‘Krankh. d. Gasarb.,’ Weyls _Arbeiterkrankh._ 1908, S. 239 ff.;
Rambousek, _Concordia 1910_, Nr. 6.


CARBON OXYCHLORIDE (PHOSGENE GAS)

‘Tödl. Verg. d. Phosgen in einer Farbenfabrik,’ _Jahresber. d. Berufsgen.
f. d. Chem. Ind._ 1905, vgl. _Gewerbl. techn. Ratgeber_, 1906, S. 108;
Klocke, ‘Mehrere gewerbl. Phosgenverg.,’ _Zeitschr. f. Gew.-Hyg._ 1906;
Sury-Bienz, ‘B. z. Kasuistik d. Intox.,’ _Vierteljahrsschr. f. ger. Med._
1907, S. 251; Müller, _Zeitschr. f. angew Chemie_, Bd. 13 (Heft v. 12.
Aug. 1910).


CARBON DIOXIDE

‘Kohlensäureverg. b. d. Kesselreinigung,’ _Zeitschr. f. Gew.-Hyg._
1906, S. 129; Kohlensäureverg. und _O_-Inhalation,’ ebenda 1906,
S. 589; Lehmann, ‘Unters. über die langdauernde Wirkung mittlerer
Kohlensäuremengen auf den Menschen,’ _Arch. f. Hyg._ 1900, S. 335.


PETROLEUM, BENZINE, &C.

_Petroleumvergiftung._—Borthenson, ‘Die Naphthaind. in sanit. Beziehung,’
Vortrag auf dem XII. Intern. Aerztekongr. in Moskau 1897 u. _D.
Vierteljahrsschr. f. öffentl. Ges.-Pfl._ 1898, Bd. 30, S. 315; Burenin,
‘Die Naphtha u. i. Verarb. in sanit. Beziehung, Petersburg 1888; Lewin,
‘Ueber allg. und Hautverg. d. Petrol.,’ _Virchows Arch._ 1888, Bd. 112,
S. 35; Sharp, ‘The Poison Effects of Petrol.,’ _Med. News_, 1888; Samuel,
‘Verg. in Petroleumtanks,’ _Berl. klin. Wochenschr._, 1904, Bd. 41, S.
1047; Foulerton, ditto, _Lancet_ 1886, S. 149; Mabille, ditto, _Revue
d’Hyg._ Bd. 18, 1896, Nr. 3; _Ber. d. engl. Gew.-Insp._; vgl. _Concordia_
1909, S. 105.

_Skin diseases in Petroleum und Paraffinarbeiter._—Chevallier, _Ann.
d’Hyg._ 1864; Lewin, _Virchows Arch._ 1888 (siehe oben); Mitchell, _Med.
News_, Bd. 53, S. 152; Derville u. Guermonprez (Papillome), _Annal.
derm._ 1890, S. 369; Brémont, _Revue d’Hyg._ 1895, S. 166; Rambousek,
_Concordia_ 1910, Nr. 6.

_Benzinvergiftung._—Dorendorf (b. Kautschukarb.), _Zeitschr. f. klin.
Med._ 1901, S. 42; Finlayson, _Brit. Med. Journ._ 1903, S. 546; Bürgi
(Verg. d. Autobenzin), _Korr. f. Schweiz. Aerzte_, 1906, Bd. 36, S. 350;
Box, _Brit. Med. Journ._ 1908, S. 807; _Zeitschr. f. Gew.-Hyg._ 1908,
S. 333, 1907, S. 157, und 1906, S. 515; Schäfer, ‘Verwendung u. schädl.
Wirkung einiger Kohlenwasserstoffe u. anderer Kohlenstoffverbindungen,’
_Hamb. Gew.-Insp.-Arb. u. Sonderberichte_, 1909, S. 7.


BENZENE

Benzolverg. b. d. Benzoldestill: _Zeitschr. f. angew. Chemie_, 1896, S.
675; _Chem. Ind._ 1906, S. 398; _Chem. Ztg._ 1910, S. 177. Benzolverg.
(Benzolextrakt.-Appar.): Egli, _Unf. b. chem. Arb._ 1903, S. 58; _Chem.
Ind._ 1907, S. 347; vgl. Lewin, _Münchn. med. Wochenschr._ 1907 und
_Zeitschr. f. Gew.-Hyg._ 1907, S. 581. Benzolverg. b. Reinigen von
Benzollagerkesseln: _Chem. Ind._ 1905, S. 444; 1907, S. 347; ferner 1909,
Nr. 14, Beil. S. 25. Benzolverg. in einer Gummifabrik: _Chem. Ind._ 1905,
S. 442. Benzolverg. bei d. Fabr. v. Antipyrin: Egli, _Unf. b. chem.
Arb._, I, 1903, S. 58. Benzolverg. d. Asphaltanstrichmasse: _Zeitschr. f.
Gew.-Hyg._ 1904, S. 292. Santesson, ‘Bensolverg. in einer Gummiw.-Fabrik.
(und exper. Untersuchungen),’ _Arch. f. Hyg._ 1897, Bd. 31, S. 336.
Rambousek, _Die gewerbl. Benzolverg. Bericht am II. Int. Kongr. f.
Gewerbekrankh. in Brüssel_ 1910. Wojciechowski, _Ueber die Giftigkeit
versch. Handelssorten des Benzols in Gasform_, Inaug.-Diss. Würzburg,
1910; Lehmann, ‘Aufnahme von Benzol aus der Luft durch Tier und Mensch,’
_Arch. f. Hyg._ 1910, Heft 4; Sury Bienz, ‘Tödliche Benzolverg.,’
_Vierteljahrsschr. f. ger. Med._ 1888, S. 138; Schaefer, ‘Verwendung u.
schädl. Wirkung einiger Kohlenw. u. anderer Kohlenstoffverbindungen,’
_Hamb. Gew.-Insp., Arb. und Sonderberichte_, 1909.


HALOGEN SUBSTITUTION PRODUCTS OF THE ALIPHATIC HYDROCARBONS (NARCOTICS)

Lehmann, ‘Aufnahme chlorierter Kohlenwasserstoffe aus der Luft durch
Mensch und Tier (Chloroform, Tetrachlorkohlenstoff, Tetrachloräthan),’
_Arch. f. Hyg._ 1910, Bd. 72, Heft 4; Grandhomme, _Die Fabr. d. A.-G.
Farbwerke in Höchst a. M. in sanit. und soz. Beziehung_, 1893, 3 Aufl.,
S. 88 (Jodmethylverg. b. d. Antipyrinbereitung); Jacquet, ‘Gewerbl.
Brom- und Jodmethylverg.,’ _D. Arch. f. klin. Med._ 1901, Bd. 71, S.
370; Schuler, ‘Gewerbl. Brommethylverg.,’ _D. Vierteljahrsschr. f.
öffentl. Ges.-Pfl._ 1899, Bd. 31, S. 696; Schaefer, ‘Verwendungsart u.
schädl. Wirkung einiger Kohlenwasserst. u. anderer Kohlenstoffverg.’
(Tetrachlorkohlenstoff),’ _Ber. d. Hamburger Gewerbe-Inspektion_, 1909,
S. 11.


HALOGEN SUBSTITUTION PRODUCTS OF THE BENZENE SERIES (CHLORBENZENE, &C.).

Leymann, ‘Erkr.-Verh. in einigen chem. Betr.,’ _Concordia_ 1906, Heft 7
(Chlorbenzol, Benzoylchlorid); ‘Verg. mit Chlorbenzol, Nitrochlorbenzol
usw.,’ _Vierteljahrsschr. f. öffentl. Ges.-Pfl._ 1902, Suppl. S. 371, und
_Concordia_ 1902, Nr. 5; Mohr, ‘Chlorbenzolverg.,’ _D. med. Wochenschr._
1902, S. 73.


HYDROXYL SUBSTITUTION PRODUCTS OF THE ALIPHATIC SERIES (ALCOHOLS)

Pohl, ‘Wirkungen von Methylalkohol,’ _Arch. f. exp. Path._ 1893, S. 281;
Patillo u. Colbourn, ‘Gewerbl. Methylalkoholverg.,’ _Ophthalm. Rec._
1899.


NITRO AND AMIDO DERIVATIVES OF BENZENE (NITROBENZENE, ANILINE, &C.)

Leymann, ‘Erkr.-Verh. in einer Anilinfarbenfabrik,’ _Concordia_ 1910,
Heft 17, S. 355; Grandhomme, _Die Fabr. d. A.-G. Farbw. in Höchst. a.
M. in sanit. u. soz. Beziehung_, 1896 (und _Vierteljahrsschr. f. ger.
Med._ 1880); ‘Nitrobenzol- und Anilinverg., Vorschr. f. d. Verhalten,’
_Zeitschr. f. Gew.-Hyg._ 1906, Nr. 22, S. 619; ‘Nitrobenzol (in
Mineralöl),’ _Zeitschr. f. Gew.-Hyg._ 1910, S. 159; Röhl, ‘Akute u.
chron. Verg. m. Nitrokörpern d. Benzolreihe,’ _Vierteljahrsschr. f.
ger. Med._ 1890, S. 202; Letheby, ditto, _Proceed. of the Roy. Soc.
London_, 1863, S. 550; Thompson, ditto, _British Med. Journ._ 1891,
S. 801; Friedländer, ‘Intox. m. Benzol- u. Toluolderivaten,’ _Neurol.
Zentralbl._ 1900; S. 294; ‘Nitrotoluolverg. in einer Sprengstoffabrik,’
_Zeitschr. f. Gew.-Hyg._ 1908, S. 383; ‘Nitroxylolverg.,’ _Chem.
Ind._ 1905, S. 444; ‘Intox. m. Nitrokörpern. u. deren Behandl. m.
Sauerstoffinhal.,’ _Zeitschr. f. Gew.-Hyg._ 1906, S. 617; Brat,
‘Gew. Methämoglobinverg. u. deren Behandl. m. Sauerstoff,’ _D. med.
Wochenschr._ 1901, S. 296; Leymann, ‘Verg. m. Nitrobenzol, Nitrophenol,
Dinitrophenol, Nitrochlorbenzol, usw.,’ _Concordia_ 1902, Nr. 5; Schröder
und Strassmann (Verg. in Roburitfabriken), _Vierteljahrsschr. f. ger.
Med._, Suppl. 1891, S. 138; Brat, ‘Erkr. in einer Roburitfabrik,’ _D.
med. Wochenschr._ 1901, Nr. 19 und Nr. 20; ‘Verg. m. Dinitrobenzol
in England,’ _Concordia_ 1909, S. 105; Mohr, ‘Verg. m. Chlorbenzol,
_D. med. Wochenschr._ 1902, S. 73; Silex, ‘Augenschädigungen d.
Nitronaphthalin,’ _Zeitschr. f. Augenheilk._ 1902, S. 178; Häusermann
und Schmidt, ‘Gewerbl. Nitrobenzol- u. Anilinverg.,’ _Vierteljahrsschr.
f. ger. Med._ 1877, S. 307; ‘Gewerbl. Anilinverg.,’ _Zeitschr. f.
Gew.-Hyg._ 1909, S. 350 u. S. 602, 1908, S. 384, 1906, S. 455, S. 599,
S. 617 u. 619 (Behandlung), 1903, S. 133, 1902, S. 63; ‘Anilinverg.
in England,’ _Concordia_ 1909, S. 105; Hildebrandt, ‘Anilinderivate,
Giftwirkung (Intern. med. Kongr. Budapest 1909),’ _Chem. Ztg._
1909, S. 997; Seyberth, ‘Blasengeschwülste d. Anilinarb.,’ _Münchn.
med. Wochenschr._ 1907, S. 1573; ‘Erhebungen über das Vorkommen von
Blasengeschwülsten bei Anilinarb.,’ _Zeitschr. für Gew.-Hyg._ 1910, S.
156; Rehn, ‘Blasengeschwülste bei Anilinarb.,’ _Arch. f. klin. Chir._
1895, S. 588; Lewin, ‘Paranitranilinverg., Obergutachten,’ _Zeitschr. f.
Gew.-Hyg._ 1909, S. 597; Criegern, ‘Gewerbl. Paraphenylendiaminverg.,’
XX. Kongr. f. inn. Medizin, Wiesbaden, 1902; Erdmann, Vahlen, ‘Wirkung
des Paraphenylendiamins,’ _Arch. f. exp. Path._ 1905, S. 401; Georgievics
(Wirkung d. Teerfarbstoffe), _Farbenchemie_, 1907, S. 13; Prosser White,
Researches into the Aromatic Compounds, _Lancet_, 1901, Case of Aniline
Poisoning, Intern. Cong. Brussels, 1910.


TURPENTINE

Lehmann, ‘Beiträge z. Kenntn. d. Terpentinölwirkung,’ _Arch. f. Hyg._
1899, S. 321; Reinhard, ‘Gewerbl. Terpentinintox.,’ _D. med. Wochenschr._
1887, S. 256; Drescher, ‘Terpentindampfinh. tödl. Verg. eines Arb. beim
Innenanstrich eines Kessels,’ _Zeitschr. f. med. Beamte_ 1906, S. 131;
Schaefer, ‘Verwendungsart u. schädl. Wirkung einiger Kohlenwasserstoffe
u. and. Kohlenstoffverbind.,’ _Hamburger Gew.-Insp., Arbeiten und
Sonderabdrücke_, 1909, S. 9.


PYRIDENE

Blaschko, ‘Möbelpoliererekzem,’ _D. med. Wochenschr._ 1890, S. 475.


TOBACCO, NICOTINE

Jehle, ‘Gesundh. Verhältn. d. Tabakarb.,’ _Arch. f. Unf.-Heilk._ 1901,
ref. _Zeitschr. f. Gew.-Hyg._ 1901, S. 236; Rochs, ‘Einfluss d. Tabaks
auf die Gesundheitsverhältnisse d. Tabakarb.,’ _Vierteljahrsschr. f. ger.
Med._ 1889, S. 104.




PART III

PREVENTIVE MEASURES


GENERAL MEASURES (NOTIFICATION, LISTS OF POISONOUS SUBSTANCES, &C.)

Fischer, _Liste der gewerbl. Gifte_ (_Entwurf_), Frankfurt a. M. (als
Manuskript gedruckt), 1910; Sommerfeld, _Liste der gewerbl. Gifte_
(_Entwurf_) Verlag Fischer, Jena, 1908; Carozzi, _Avvelenamenti ed
infezioni professionali_ (_gewerbl. Gifte und Infektionen_), Verlag
Fossati, Mailand, 1909; Rambousek, _IIᵉ Congrès int. des maladies prof.
Bruxelles_ 1910, S. 14; ‘Anzeigepflicht bei gewerbl. Erkrankungen,’
Ber. über die Verh. d. Abt. f. Gewerbekrankh. auf der 36. Jahresvers.
der British med. Assoc. in Sheffield 1908, _Brit. Med. Journ._ 1908, S.
401-408 und 480-496; Rambousek, ‘Arbeiterschutz und Versicherung bei
gewerbl. Erkrankungen,’ _Sozialtechnik_ 1909, Heft 4, S. 65; Lewin,
_Grundlagen für die med. und rechtl. Beurteilung des Zustandekommens und
des Verlaufes von Vergiftungs- u. Infektions-Krankheiten im Betriebe_
(Monogr.) Berlin, Heymanns Verlag, 1907.


SULPHURIC ACID INDUSTRY

‘Schwefelsäureerzeugung, Schutz gegen Nitroseverg.,’ _Gewerbl. techn.
Ratgeber_, 1906, Heft 6, S. 109; ‘Schwefelsäureerzeugung, Reinigung
von Tankwaggons,’ _Gewerbl. techn. Ratgeber_, 1906, Heft 6, S. 109;
‘Schwefelsäuretransport,’ _Zeitschr. f. Gew.-Hyg._ 1902, Nr. 4, S. 63;
‘Schwefelsäureverg., Verhütung,’ _Chem. Ind._ 1909, Beilage, _Ber.
d. Berufsgen. f. d. chem. Ind. f. d. J._ 1908, S. 26; ‘Ausräumen des
Gay-Lussac, Verhütung von Verg., _Chem. Ind._ 1907, S. 351; ‘Sauerstoff
gegen Schwefelsäureverg., Atemapparate,’ _Zeitschr. f. Gew.-Hyg._ 1906,
Nr. 20, S. 562, und 1906, Nr. 22, S. 617.


PETROLEUM, BENZINE

Berthenson, ‘Die Naphthaindustrie in sanit. Beziehung,’
_Vierteljahrsschr. f. öffentl. Ges.-Pfl._ 1898, Bd. 30, S. 315;
Korschenewski, _Wratsch_, 1887, Nr. 17; Burenin, ‘Die Naphtha und ihre
Verarbeitung in sanit Beziehung,’ Petersburg 1888; Mabille, ‘Revue
d’Hygiène,’ Bd. 18, Nr. 3; _Bericht der Berufsgen. f. chem. Ind._ 1905;
_Bericht der preuss. Gew.-Insp._ 1904; Klocke, _Zeitschr. f. Gew.-Hyg._
1908, S. 379; ‘Benzinersatz (in chem. Wäschereien),’ _Zeitschr. f.
Gew.-Hyg._ 1906, S. 248, und 1908, S. 384; ‘Schutz des Arbeiters vor
Benzindämpfen,’ _Zeitschr. f. Gew.-Hyg._ 1906, S. 236.


CARBON BISULPHIDE

‘Nachweisung von Schwefelkohlenstoffdämpfen in Fabrikräumen,’
_Zeitschr. f. Gew.-Hyg._ 1908, Nr. 5, S. 107; ‘Hygienische
Einrichtung beim Vulkanisieren (Glibert),’ _Zeitschr. f. Gew.-Hyg._
1902, Nr. 1, S. 1; ‘Absaugung der Dämpfe an Vulkanisiertischen,’
_Zeitschr. f. Gew.-Hyg._ 1903, Nr. 14, S. 305; Laudenheimer, ‘Die
Schwefelkohlenstoffverg. bei Gummiarbeitern,’ Leipzig, Veit & Comp.,
1899; Roeseler,’Schwefelkohlenstofferkrankungen und deren Verhütung,’
_Vierteljahrsschr. f. Med. u. öffentl. Sanitätswesen_ 1900, 3. Folge, Bd.
20, S. 293 (ref. _Zeitschr. f. Gew.-Hyg._ 1901, S. 164); ‘Einrichtungen
von Gummifabriken,’ _Zeitschr. f. Gew.-Hyg._ 1903, S. 260 u. 484.


ILLUMINATING GAS

‘Leuchtgasverg.-Verhütung,’ _Zeitschr. f. Gew.-Hyg._ 1909, Heft 22, S.
604; ‘Kokslöscheinrichtung,’ _Zeitschr. f. Gew.-Hyg._ 1908, Heft 10, S.
231; ‘Bedeutung der Sauerstoffinhalationen in der Leuchtgasindustrie,’
_Zeitschr. f. Gew.-Hyg._ 1906, Heft 21, S. 590; ‘Entleerung der
Reinigungskästen in der Leuchtgasfabrik, _Zeitschr. f. Gew.-Hyg._
1903, Nr. 13, S. 283; Jehle, ‘Hygiene der Gasarbeiter,’ _Zeitschr. f.
Gew.-Hyg._ 1901, Nr. 14, S. 245.


COAL TAR COLOURS (ANILINE FACTORIES)

Grandhomme, _Die Fabriken der A.-G. Farbwerke vorm. Meister, Lucius &
Brüning zu Höchst a. M._, Frankfurt a. M. 1896; Leymann, ‘Ueber die
Erkrankungsverhältnisse in einer Anilinfabrik,’ _Concordia_ 1910,
Heft 17, S. 355 ff.; Leymann, _Die Verunreinigung der Luft durch
gewerbliche Betriebe_ (Fischer, Jena, 1903); ‘Sauerstoffinhalationen in
Anilinfabriken,’ _Zeitschr. f. Gew.-Hyg._ 1906, Nr. 22, S. 617, und 1908,
S. 327.


LEAD (GENERAL)

Legge & Goadby, ‘Lead Poisoning and Lead Absorption,’ 1912; _Bleiverg.
in gewerbl. u. hüttenmänn. Betrieben Oesterreichs_, herausgeg. vom. k.
k. Arbeitsstatist. Amte, I-VI, Verlag Hölder, 1905-1909; Leymann, _Die
Bekämpfung der Bleigefahr in der Ind._, Verlag Fischer, Jena, 1908;
Wächter, _Die gewerbl. Bleiverg. im Deutschen Reiche_, Verlag Braun,
Karlsruhe 1908; Blum, ‘Untersuch, über Bleiverg., Frankfurt a. M. 1900,’
_Wiener klin. Wochenschr._ 1904, S. 1935; Rambousek, _Ueber die Verhütung
der Bleigefahr, Wien_, Hartleben, 1908; Teleky, ‘Die gewerbl. Bleiverg.
in Oesterr.,’ _Sozialtechnik_ 1909, S. 333, _Wiener klin. Wochenschr._
1907, S. 1500.


LEAD SMELTING

_Bleiverg. in gewerbl. u. hüttenmänn. Betrieben Oesterr._, I und
III, Verlag Hölder, Wien; Müller, _Die Bekämpfung der Bleigefahr in
Bleihütten_, Verlag Fischer, Jena, 1908; Wutzdorff, _Bleiverg. in
Zinkhütten_, Arb. a. d. Kaiserl. Ges.-Amte, Bd. 17, S. 441; Elsässer,
‘Schädl. in Blei- und Silberhütten,’ _Vierteljahrsschr. f. ger. Med._
1903, Bd. 25, S. 136.


PAINTS AND COLOUR FACTORIES

Über Hygiene der Erzeugung und Verwendung von Bleifarben: _Bleiverg.
in gewerbl. u. hüttenm. Betrieben Oesterreichs_, IV., V. und VI. Teil,
_Hölder Wien_; Stüler, ‘Bleiverg. bei Malern’; _Vierteljahrsschr. f.
öffentl. Ges.-Pfl._ 1895, S. 661; ‘Bleiweissfabriken (Staubabsaugung),’
_Zeitschr. f. Gew.-Hyg._ 1909, Nr. 22, S. 601; ‘Kampf gegen die
Bleifarben in Frankreich,’ _Zeitschr. f. Gew.-Hyg._ 1909, Nr. 23, S. 543;
‘Gefahren in Bleiweissfabriken,’ _Zeitschr. f. Gew.-Hyg._ 1907, Nr. 9,
S. 205; ‘Bleiweissersatz (Ausstellung),’ _Zeitschr. f. Gew.-Hyg._ 1907,
Nr. 11, S. 254; ’ Bleifarbenverbot,’ _Zeitschr. f. Gew.-Hyg._ 1904, Nr.
10, S. 221; ‘Bleigefahr im Gewerbe der Anstreicher, Maler usw.,’ _Soz.
Technik._ 1909, Nr. 17, S. 333; ‘Bleiweissfrage,’ _Sozialtechn._ 1908,
Nr. 16, S. 310.


ELECTRIC ACCUMULATOR FACTORIES

Wutzdorff, _Bleiverg. in Akkumul.-Fabr._, Arb. a. d. Kaiserl. Ges.-Amt
1908, Bd. 15, S. 154; ‘Hygiene der Akkumulatorräume,’ _Zeitschr. f.
Gew.-Hyg._ 1909, Heft 3, S. 79, und Heft 21, S. 494; Chyzer, ‘Hygiene
der Akkumulatorräume,’ _Zeitschr. f. Gew.-Hyg._ 1907, Nr. 20, S. 476;
‘Bekämpfung von Verg. in Akkumulatorräumen,’ _Concordia_ 1908, Heft 13,
S. 273.


LETTERPRESS PRINTING

_Bleiverg. in gewerbl. u. hüttenm. Betrieb. Oesterr._, k. k.
Arbeitsstat. Amt, VII. Teil, Wien, Hölder 1909; Panwitz, _Bleiverg. in
Buchdruckereien_, Veröff. d. Kais. Ges.-Amtes, Bd. 17, S. 503; ‘Bleiverg.
in der Buchdruckerei (Enquete),’ _Zeitschr. f. Gew.-Hyg._ 1909, Heft 6,
S. 152 ff.; ‘Bleifreie Druckfarben und Bronzen (Preisausschriebung),’
_Zeitschr. f. Gew.-Hyg._ 1909, Heft 23, S. 630 ff.; ‘Setzkasten mit
doppeltem Boden,’ _Zeitschr. f. Gew.-Hyg._ 1908, Nr. 10, S. 237;
‘Bleinachweis in den Dämpfen der Typengiesserei,’ _Zeitschr. f.
Gew.-Hyg._ 1906, Nr. 24, S. 677; ‘Schriftsetzerei (Typenbläserei),’
_Zeitschr. f. Gew.-Hyg._ 1904, Nr. 8, S. 176; ‘Bleigefahr in
Druckereien,’ _Concordia_ 1908, Heft 18, S. 384.


FILECUTTING

‘Bleiverg. bei Feilenhauern in England,’ _Zeitschr. d. Zentralst. f.
Arb.-Wohlf.-Einr._ 1901, S. 232; ‘Bleierkr. b. Feilenhauern,’ _Gewerbl.
techn. Ratgeber_ 1905, Heft 3, S. 50; ‘Hygiene d. Feilenhauerei
(Chyzer),’ _Zeitschr. f. Gew.-Hyg._ 1908, N. 13, S. 303.


ZINC SMELTING

Frey, _Die Zinkgewinnung im oberschles. Industriebezirk und ihre
Hygiene_, Berlin 1907, Verlag Hirschwald; Sigel, ‘Das Giesserfieber und
seine Bekämpfung,’ _Vierteljahrsschr. f. ger. Med._ 1906, Bd. 32, S.
173; ‘Lehmann, Beiträge zur hyg. Bedeutung des Zinks,’ _Arch. f. Hyg._
1897, Bd. 28, S. 300; ‘Giess- oder Zinkfieber,’ _Arch. f. Hyg._ 1910,
Bd. 72, S. 328; ‘Hyg. der Zinkerei,’ _Zeitschr. f. Gew.-Hyg._ 1907, Nr.
2, S. 39; ‘Zinkhütten, hyg. Einricht.,’ _Zeitschr. f. Gew.-Hyg._ 1901,
Nr. 18, S. 321, und 1910, Heft 11, S. 250; ‘Giesserfieber, Bekämpfung,’
_Soz. Techn._ 1907, Heft 3, S. 51; ‘Giesserei, Hyg.,’ _Zeitschr. f.
Gew.-Hyg._ 1903, Heft 16, S. 351, Heft 21, S. 479, und 1904, Heft 13, S.
344, ‘Schutz gegen Säuredämpfe bei der Metallbearbeitung,’ _Zeitschr. f.
Gew.-Hyg._ 1904, Heft 1, S. 5 u. 11, ferner Heft 14, S. 317, u. 1905,
Heft 10, S. 287, Heft 22, S. 643.


MERCURY

Quecksilberhütten in Idria: Laureck in Weyls _Handb. d. Arb.-Krankh._
1909, S. 62; ‘Quecksilberhütten in Amiata’: Giglioli, _Ramazzini_ 1909,
Bd. 3, S. 230.

Quecksilberbelegerei, Hyg: Schönlanck, _Fürther Spiegelbelegen_ (Monogr.)
1888; Wollner, ‘Fürther Spiegelbelegen,’ _Vierteljahrsschr. f. öffentl.
Ges.-Pfl._ XXIX 3, S. 421, und _München. med. Wochenschr._ 1892, Bd. 39,
S. 533; Charpentier, ‘Fürther Spiegelbelegen,’ _Ann. d’Hyg. publ._ 1885,
S. 323.

Quecksilber in Hutfabriken, Quecksilberbeize: Stickler, _Revue d’Hygiène_
1886, S. 632; Henke (Monogr.), Frankfurt a. M. 1899; Hasenfellbeize
(Ersatz), _Jahresber. d. Fabr.-Insp._ 1884, S. 489, _Zeitschr. f.
Gew.-Hyg._ 1902, S. 360, 1909, S. 281, _Soz. Techn._ 1910, S. 39;
Hutfabriken in Italien (Hyg.), _Ramazzini_ 1909, S. 230.

Sonstige Gewerbe: Glühlampenind. (Hyg.): Donath, _Wiener med.
Wochenschr._ 1894, S. 888, _A. Mitt. a. d. Ber. d. Gew.-Insp._ 1899,
_Zeitschr. f. Gew.-Hyg._ 1902, Heft 20, S. 356, und 1908, Heft 20, S.
469, Thermometererzeug. (Hyg.), _Zeitschr. f. Gew.-Hyg._ 1901, S. 32.


ARSENIC

‘Arsenikbestimmung im Hüttenrauch’ (Harkins & Swein), _Journ. Amer.
Chem. Soz._ 1907, Bd. 29, S. 970; _Chem. Ztg._, Rep. 1907, S. 447;
‘Arsenikverg. in der Ind.’ (Heim, Herbert), _Zeitschr. f. Gew.-Hyg._
1907, Bd. 14, S. 354; ‘Arsenverg. in der Delainage,’ _Zeitschr.
f. Gew.-Hyg._ 1906, Nr. 3, S. 71; ‘Gewerbl. Arsenverg.’ (Legge),
_Zeitschr. f. Gew.-Hyg._ 1903, Heft 21, S. 476; ‘Arsenwasserstoffverg.
im Gewerbe (Prophyl.),’ _Zeitschr. f. Gew.-Hyg._ 1908, Nr. 10, S.
229; ‘Arsenwasserstoff im Ballongas (Beseitigung),’ _Zeitschr. f.
Gew.-Hyg._ 1908, Nr. 11, S. 263; ‘Arsenwasserstoff beim Ausleeren von
Schwefelsäuretanks (Verhütung),’ _Gewerbl. techn. Ratgeber_ 1906, Heft 6,
S. 109; ‘Arsenfreier Wasserstoff zum Löten,’ _Gewerbl. techn. Ratgeber_
1906, Heft 10, S. 173; und _Zeitschr. f. Gew.-Hyg._ 1905, Heft 9, S. 252;
‘Befreiung der Salzsäure vom Arsengehalt,’ _Zeitschr. f. Gew.-Hyg._ 1903,
Heft 21, S. 477.




INDEX


Heavy type (Transcriber’s Note: =like this=) refers to the main treatment
of the subject and the Roman figures in brackets following to the Part of
the book: (i) Occurrence of Poisoning; (ii) Pathology; (iii) Preventive
Measures.


  Absorption towers, 256, 258, 289

  Accumulator manufacture, =135= (i), 145, 295, =305-9= (iii)

  Acetic acid, 9, 46, 333

  Acetylene, 52, =85-87= (i), =278= (iii), 279

  Acrolein vapour, 326

  Aerograph, 138

  Akremnin soap, 294

  Alcohol, 99, 100, 210, 216, 333

  Alcoholism, 241

  Aliphatic series. See Hydrocarbons

  Alizarin, 111, 113
    colours, 3, 10, 57, 96, 111, 112, 114

  Alkaline bromides, 36
    hydroxides, 176

  Alkaloids, 216

  Alternation of employment, =227= (iii), 293, 299

  Amalgam. See Mercury amalgam

  Amido compounds, 110, 112, 201, 211, =212= (ii), 287

  Amines, 33, 107, 111

  Ammonia, 44, 68, 71, 72, 76-79, 82, =90-93= (i), 94, =175= (ii), =279=
      (iii), 280

  Ammonia soda process, 14, =20= (i), 92, 258

  Ammonium carbonate, 44, 91, 92
    compounds, 67, =90= (i), 92, =174= (ii), =279= (iii)
    nitrate, 44, 115
    oxalate, 115
    phosphate, 50, 92
    superphosphate, 55

  Amyl alcohol, 45, 210
    nitrite, 45, 46, 212

  Aniline, 3, 57, 69, 70, 96, 105, 109, 111, 112, 114, =116-119= (i), 145,
      156, =212-214= (ii), =286-288= (iii)

  Aniline black, 117, 156
    colours, 3, 4, 57, 112, 115, 117, 118, 156, 214, =285-288= (iii)
    oil, 117, 214
    poisoning, 3, 69, 113, =116-119= (i), =212-214= (ii), =256-288= (iii)

  Animal products, 154

  Anthracene, 3, 60, 96-97, 101, 107, 108, 111, 113, 285

  Anthraquinone, 55, 111

  Antimony, 122, 124, =146= (i)
    chloride and oxide, 37

  Antipyrin, 3, 4, 36, 102, 104, 114

  Argyria, =45=, 152, 188, 329. See also Silver

  Aromatic series. See Hydrocarbons

  Arsenic, 12, 65, 119, 122, =143-146= (i), 154, 189, =159= (ii), 257,
      323, =328-329= (iii)

  Arseniuretted hydrogen gas, 12-14, 32, 113, 114, =145-146= (i), 148,
      149, 188, 189, =197= (ii), 257, 279, 286, 316, =328-329= (iii)

  Artificial manure, 38, =53= (i), 54, 55, 92, =176= (ii), =261-265= (iii)

  Artificial respiration, 164, =284= (iii)

  Asphalt, =98= (i), 285

  Aspirin, 102

  Azo-colours, 96, 110, 214


  Balloon filling, 145, 329

  Barium chloride, 16, 66
    nitrate, 44

  Barometers, manufacture of, 141, 142, 328

  Baryta, 66, 67, 135

  Basic slag, 49, 53, =54= (i), 148, =261-264= (iii)

  Basophil granules, 178

  Baths, 237, 292

  Beer brewing, 65, 154, 333

  Benzalchloride, 35, 110, 287

  Benzaldehyde, 35, 109

  Benzene (Benzene poisoning), 3, 4, 69, 77-79, 85, 96, =99-100= (i), 101,
      102-106, 112-114, =204-208= (ii), =285-286= (iii), 288, 330

  Benzidine, 118

  Benzine, 34, 53, 54, =59= (i), =61=, 62, 63, 64, 68, 69, 85, 96, 156,
      203, =204= (ii), =267= (iii), 268, 330

  Benzol. See Benzene

  Benzo-trichloride, 35, 109, 287

  Benzoyl chloride, 35, 209

  Benzyl chloride, 35

  Bessemer process, 148

  Beth filter, 254

  Bichromate, 50, 54, 55. See Chromates

  Bladder, cancer of, 114, 117, 214

  Blast furnace, =146= (i), =289= (iii)
    gas, 65, 82, 88, =89= (i), 146, =289-290= (iii)

  Blasting gelatine, 47

  Bleaching, 156, 337
    powder, =26= (i), =259= (iii)

  Blood poisons, 158, 164, 199-201, 211-214

  Bone extraction, 68, 69, 267

  Boracic acid, 138

  Bottle capsules, 323

  Brass (brass-casters’ ague), =152= (i), =182= (ii), 188, =325= (iii)

  Breathing apparatus, =231-237= (iii), 267, 286, 288, 290, 310

  Briquettes, 96, 101

  Bromine, =29= (i), 36, 52, =173= (ii)

  Bronze, 45, 139, 316

  Brunswick green, 144

  Butyl alcohol, 210

  Butyric acid, 75


  Calamine, 125

  Calcium carbide, 52, =85= (i), 87, 90, 278
    sulphide (soda waste), 18

  Calomel, =143=

  Camphor, 49

  Cancer, 64, 102, 114, 118, 203, 214

  Carbon bisulphide, poisoning by, 30, 31, 34, 50, 65, =68= (i), 68-71,
      74, 80, 93, 96, 104, 156, 192, =193-195= (ii), =271-275= (iii)
    oxychloride, =32= (i), 33, =294= (iii)
    tetrachloride, =34= (i), 69, 208, 268, 275

  Carbonic acid gas (carbon dioxide), =17=, 50, 53, 54, 68, 74, 82, 131,
      149, 153, =201-202= (ii), 330, 332
    oxide, 17, 21, 31, 32, 50, 74-76, 80, 82, =87-90= (i), 102, 107, 119,
      148, 149, 153, 154, 156, 188, =199-200= (ii), 288, 289, 323, 330,
      332

  Carbonising, 156, 336

  Carborundum. See Silicon carbide

  Carburetted gas, 61, 83, 87

  Caustic alkali, 25
    potash, 3, 25, 34, 176
    soda, 18, 19, 25, 36, 157, 176

  Celluloid, 48, 49

  Cellulose, 156, 336

  Chamber acid, 5, 8, 53, 258

  Chance-Claus process, 19

  Chemical cleaning. See Benzine industry, =1= (i), 134, 145, =256= (iii)

  Chili saltpetre, 35, 39, 41, 45, 54

  Chloral, 34

  Chlorates, =23= (i), 25, 26, 29, 30, 52

  Chloride of lime. See Bleaching powder
     sulphur, 31, 32, 68, 70, 174, 272-274

  Chlorides, =30= (i), =174= (ii)

  Chlorine, =23= (i), 25, 26, 27, 30-32, 34, 35, 39, 44, 52, 58, 156,
      =173= (ii), 209, =259= (iii), 285
    rash, 28, 35, 173, 174, 209, 259

  Chlorine compounds, organic, 27, 69, 209, 285

  Chloroform, 26, 33, 34, 208

  Chrome colours, 55, 56, 265
    poisoning, 52, =56= (i), 57, 58, 114, 153, =185= (ii), =265= (iii)
    tanning, =55= (i), 57, 58, =266= (iii)
    yellow, 44, 55, 57

  Chromium (chromates), 3, 52, =55= (i)-58, 114, 134, 153, =185= (ii),
      =265= (iii), 271

  Coal tar. See Tar

  Cobalt, =144=

  Coke ovens, =77= (i), 78, 79, 92, 102, 104, =276= (iii)

  Compositors. See Printing

  Condensation, =255= (iii), 323, 327
    of mercury, 141
    zinc, 125

  Copper, =151= (i), =188= (ii)

  Cresols, 96, 101, 109

  Cumene, 207

  Cyanogen, 77, =93= (i), 152, =195= (ii), 261, 279, =280= (iii)
    compounds, 71, 79, 92, =93= (i), 94, 95, 103, 152, 154, =195= (ii),
      196, 262, 279, =280= (iii), 289


  Deacon process, 23, 28

  Denitration, 6, 43, 47, 48, 287

  Desilverising, 124, 126, 128

  Diaphragm method (chlorine), 24

  Diazo-compounds, 110, 286

  Diethyl sulphate, 23

  Digestive tract, diseases of, 76, 129, 130, 133, 179, 182, 186

  Dimethyl aniline, 109

  Dinitrobenzene, 35, 108, 112, 115, 116, 212

  Dinitrochlorobenzene, 115, 209, 212

  Dinitrophenol, 115, 212, 213

  Dinitrotoluol, 108, 212

  Distillation, 253, 255
    of alcohol, 333
    petroleum. See Petroleum distillation
    tar. See Tar distillation

  Dowson gas, 82, 83, 87, 276

  Dräger’s oxygen apparatus, 165-167

  Dry cleaning. See Benzine

  Dust removal, =243-256= (iii). See also Ventilation

  Dye stuffs, =107-119= (i), =214= (ii), =285-288= (iii), 337

  Dyeing and colouring, 44, 45, 55, 57, 92, 134, 144, 156, 265, 310-316,
      337

  Dynamite, 43, 47


  Earthenware. See Pottery

  Eczema, 64, 186

  Electric furnace, 85

  Electroplating, 196, 327, 329

  Enamel, 135, 322

  Encephalopathy, 181

  Etching on glass and metal, 37, 40, 45, 57

  Ether, 68, 69

  Ethyl alcohol, 34, 210
    chloride, 34

  Explosives, =45= (i), 49, 115, =260= (iii)

  Extraction, 54, 61, =68= (i), 68-69, 71, 100, 103, 117, 186, =253=
      (iii), 267, 272-274

  Eye affections, 21, 23, 38, 55, 57, 65, 68, 70, 75, 93, 115, 116, 119,
      171, 174, 175, 210


  Fans, =244-247= (iii). See also Ventilation

  Fat extraction, 34, 61, 68, 70, 71, 272-274

  Fermentation, 154, 333

  Ferrosilicon, 53, 85, 146, =149-151= (i), 199, =291= (iii)

  File cutting, =140= (i), 294, =322-323= (iii)

  Fluorine. See Hydrofluoric acid

  Fluorine compounds, 37, 54, 153, 171, 265

  Flux, 135, 149

  Frit, 135, 136, 137, 138, 320

  Fuchsin, 111, 113, 119, 144, 287

  Fulminate of mercury, =46= (i), 143, 261


  Galvanising, 94, 95, 152, 326, 329

  Gas engines, 82, 88, 89, 100, =276-278= (iii)
    lighting, =71-89= (i), 92, 93, 175, =275= (iii)
    lime, 65, 94, 153, 275
    purifying material, 5, 65, 68, 74, 75, =93= (i), =275= (iii), 276

  Gay-Lussac tower, 5, 6, 10, 11, 256, 257, 287

  Generator gas. See Producer gas

  Glass etching, 37, 38, 153, 330
    industry, 19, 37, 39, 55, 58, 82, 88, 138, 143, =153= (i), 322
    pearl silvering, 152

  Glazing, =135-138= (i), =319-322= (iii)

  Glover acid, 6, 8
    tower, 5, 6, 257, 287

  Gold, 44, 94, 125, 152

  Gun-cotton, 47-49

  Guttapercha, 69


  Hæmolysis, 158

  Halogens, =31= (i), =173-174= (ii)

  Hargreaves process, 19, 28

  Hatters’ furriers’ processes, 45, 141, 142, 154, 327

  Hausmannite, 58

  Health register, 227, 264, 274, 298, 304, 307

  Hides and skins, preparation of, 142, 143, 144, 184, 327

  Hops, sulphuring of, 154, 333

  House painting, 121, 122, =132-133= (i), 294, =314-316= (iii)

  Hydrocarbons, 96, 106, 158, 286, 287, 330, 331
    (aliphatic), 96, 202
    (aromatic), 96, 108, 109, 202, 204, 330

  Hydrochloric acid, =14= (i), 15, 20, 21, 23, 30-35, 39, 44, 50, 54, 59,
      113, 145, 131, =170= (ii), =257-258= (iii), 286, 326

  Hydrofluoric acid, =29= (i), 37, 38, 50, 54, 96, 153, =171= (ii),
      =265= (iii)

  Hypochlorite, 25, 30


  Incandescent lamps, 141, 327

  Indiarubber, 31, 61, 63, =68-71= (i), 100, 103, 134, 194, 267,
      =271-274= (iii)

  Indigo, 34, 92, 111

  Injectors, 245

  Insurance, Workmen’s, 224

  International Labour Bureau, 219

  Iodine, =30= (i), 36, =173= (ii)
    compounds and poisoning, 36

  Iron, 44, 124, 144, =146-149= (i), =289-291= (iii)


  Kidney disease, 57, 130, 181, 185, 215


  Lampblack, 97

  Lead, 8, 13, 29, 44, 55, 68, 69, =120-140= (i), 144, 149, 152, 156,
      =177-182= (ii), 329
    acetate, 55, 131, 134
    burning, 140, 323
    carbonate. See White lead
    chloride, 55, 181
    chromate, 55, 57, 132, 134, 138, 310
    colic, 179. See Lead poisoning
    colours, =131-134= (i), 293, 294, 295, =310-316= (iii)
    nitrate, 50, 55
    oxide, 44, 45, 122, 131, 134, 135, 136, 137, 181
    piping, 140, 323
    poisoning, 3, 13, 44, 69, 93, 114, =120-122= (i), 146, 149-152,
      =177-182= (ii), =292-323= (iii)
    silicate, 135
    smelting, =122-131= (i), =299-305= (iii)
    sulphate, 55, 122, 181
    sulphide, 122, 131, 136, =293= (iii)

  Leblanc soda process, =14= (i), 18, 19

  Light oils, 98

  Ligroine, 61

  Lime kilns, 55, 153, 330

  Litharge, 124, 126, 129, 131, 132, 134, 135, 138, 300-305

  Lithopone. See Zinc white

  Lungs, diseases of, 9, 40, 54, 68, 75, 76, 106, 118, 169-177, 189, 201,
      204, 213-216


  Mahogany, 156

  Malt drying, 333

  Manganese (manganese poisoning), 23, 29, =58= (i), 59, 153, =179-180=
      (ii)

  Meal rooms, 236

  Mercaptan, 22, 96

  Mercury and mercury poisoning, 40, 44, =141= (i), 152, 154, =184= (ii),
      =326-327= (iii), 329
    amalgam, 141, 142, 327

  Metals, recovery of, =120= (i), =176= (ii) =288= (iii)

  Metaphenylene diamine, 118

  Methyl alcohol, 33, 34, 36, 37, 107, 156, 209, =210= (ii), 336
    bromide and iodide, 36, 209
    chloride, 33, 209
    violet, 112, 119

  Methylamine, 96

  Methylene chloride, 34, 208

  Mineral acids, =169-172= (ii)

  Mineral oil, =59= (i), 60-63, 64, 65, 85

  Mirbane, oil of. See Nitrobenzene

  Mond gas, 82, 87

  Mordants, 32, 55, 337

  Muffle furnace, 15, 20, 22, 125, 137, 138, 143, 258, 325


  Naphtha. See Petroleum
    vapour, 42, 63, 267
    wells, 61, 62, 267

  Naphthalene, 74, 96, 100, 101, 113, =208= (ii)

  Naphthol, 9, 96, 101, 109, 110
    yellow, 110

  Naphthylamine, 103, 110, 118, 287

  Narcotic poisons, 208, 209

  Nephritis. See Kidney disease

  Nerve poisons, 158, 192, 205

  Nervous diseases, 70, 107, 163, 181, 184, 189, 190, 193, 194, 196, 197,
      199, 202, 204, 205, 215

  Nickel, 144, =186= (ii)
    carbonyl, =186-188= (ii)
    eczema, 186

  Nicotine, 216

  Nitrating, 41-43, 47, 49, =108= (i), =261= (iii), 286

  Nitric acid, 2, 6, 9, 10, =39= (i), 43-49, 107, 116, 182, =172= (ii),
      =260= (iii), 261, 285-287, 326

  Nitrobenzene, 3, 9, 35, 40, 41, 45, =108-115= (i), =212= (ii),
      =285-288= (iii)

  Nitro-cellulose, 40, 42, 47, 48, 336

  Nitrochlorobenzene, 116, 209

  Nitro-compounds, 40, =108= (i), 109-112, 114, 115, =211-214= (ii),
      =286-288= (iii)

  Nitro-glycerin, 9, 40, 41, 43, =46= (i), 47, 48, =212= (ii), =261= (iii)

  Nitronaphthalin, 115, 116, 214

  Nitrophenol, 3, 46, 115, 212, 288

  Nitrous fumes, 10, 12, =40-44= (i), 48, 116, 171, =261= (iii), 286, 326

  Notification of poisoning, =220-225= (iii)


  Oil, extraction, 61, 68, 69, 267

  Organ pipe making, 140

  Oxalic acid, 55, 259

  Oxygen inhalation, 43, 63, 64, =164-168= (ii), 188, 192, 196, 200-202,
      204, 208, 227, =231-237= (iii)


  Painting. See House painting

  Paints (quick-drying), =330-332=

  Paper, manufacture of, 336

  Paraffin, 50, 59, 60, 96, 98, 101, 107, 203
    eczema, 27, 64, 65, 102, 203

  Paranitraniline, 114, 118, 214

  Paraphenylene diamine, 118, 214

  Parkes’ process, 125, 127

  Pattinson process, 125, 127

  Petrol ether, 60, 331

  Petroleum (petroleum poisoning), =59-65= (i), =202-204= (ii), =267= (iii)

  Phenanthrene, 96

  Phenol, 75, 90, 96-100, 108, 109

  Phenylhydrazine, 36

  Phosgene. See Carbon oxychloride

  Phosphor bronze, 52

  Phosphoretted hydrogen gas, 50, =52= (i), 86, 90, 149, =191-192= (i)

  Phosphorus, 31, 36, =49= (i), 50, 52, 148, 149, =190-191= (ii),
      =268-271= (iii)
    necrosis, =51= (i) 52, =190-191= (ii), =268-271= (iii)
    prohibition of, 51, 220, =268-271= (iii)

  Photography, 36, 45, 58, 94, 152

  Picric acid, 40, 96, 100, 108, 115, 116, =213= (ii)

  Pitch, 96, 97, 107, 281, 282

  Plate towers, 7, 16, 39

  Poisons, classification of, =157-163=, =169= (ii)

  Porcelain, =138= (i), 322

  Potassium bichromate. See Chromium chlorate, 26, 29, 37, 50, 52

  Pottery, =135-138= (i), 153, 294, =319-321=

  Power gas, =80-90= (i), =277= (iii)

  Printing, =138-139= (i), 146, =317-319= (iii)

  Producer gas, 80-82, 87-89, 153, 276-278

  Propyl alcohol, 248, 249

  Prussic acid. See Hydrocyanic acid

  Pulmotor, 167, 168

  Pyridine, 59, 90, 96, 101, 152, =216= (ii), 285

  Pyrites burner, 5, 6, 65, 256

  Pyroxyline, 48, 261


  Quick-drying paints, =330-332=

  Quicklime, 54, 73

  Quinoline bases, 110


  Realgar. See Arsenic

  Refrigeration, 92, 93, 154

  Regenerator firing, 81, 148, 153

  Rescue appliances, =164-168= (ii), =230-235= (iii)

  Respirators, =229= (iii)

  Roasting (calcining furnaces, &c.), 5, 11, 65, 119, 120, 125-127, 129,
      130, 131, 141, 143, 253, =288-289= (iii), 299, 323, 327

  Roburite, 115, 116

  Roofing felt, 96, 101, 281

  Rubber. See Indiarubber


  Salt, 32, 33

  Saltcake. See Sodium sulphide

  Saltpetre, 35, 42, 50, 257

  Satinwood, 154, 155

  Sewer gas, 66, 67, 93, 95

  Shot, 121, 140, 143

  Silicon carbide, 85, 140, 323

  Silicofluoric acid, 38, 50, 54, 171

  Silk, artificial, 49

  Silver (argyria), 45, 92, =120= (i), 122-125, 144, 152
    nitrate, 40, 45, 142, 188, 227
    smelting, =122=, =131= (i)

  Skin diseases, 27, 38, 47, 52, 55, 56, 58, 62, 64, 65, 71, 96, 102, 107,
      118, 143, 144, 154-156, 171, 173, 185-189, 203, 208, 209, 265

  Smelting processes, 89, 94, =119= (i), 143, 144, 182, =288-290= (iii),
      299, 323-325, 326

  Smokeless powder, 49, 211

  Soda, 2, =14= (i), 17-20, 55, 65, 92, 95, =258= (iii)
    electrolytic, 20
    waste, 18, 65, 258

  Sodium bichromate. See Chromate sulphate and sulphide, =14= (i), 17,
      19-22, 22, 112, =258= (iii), 286

  Soldering, 145, 316, 329

  Solvay method. See Ammonia soda

  Solvent naphtha, 99-102, 106, =207= (ii), 330

  Spirit, denaturing of, 99, 100, 210, 216

  Substitutes for poisonous materials, =243= (iii)

  Suction gas, =82= (i), 83, 87-89, =276-278= (iii)

  Sulpho-cyanide compounds, 75, 90, 93

  Sulphonal, 22, =259= (iii)

  Sulphur, 31, 52, =65= (i), 65, 68, 74, 93, 122, 288

  Sulphur dioxide, =5= (i), 9, 13, 14, 19, 21, 23, 31, 54, 63, 65, 119,
      120, 122-125, 148, 154, =171= (ii), =257= (iii), 259, 267, 279,
      288, 323, 326, 327, 333
    dyes, 112
    soap, 294

  Sulphuretted hydrogen, 8, 12, 13, 16, 18, 21, 50, 52-54, =65= (i), 66,
      67, 74, 79, 90-93, 95, 96, 101, 102, 103, 106, 107, 112, 114, 175,
      =192= (ii), 193, 258, 271, 279, 280, 285, 286, 290

  Sulphuric acid, =5= (i), 9, 14, 18-20, 23, 33, 37-41, 46, 47, 49, 50,
      53, 54, 60, 64, 65, 67, 92, 93, 108, 112, 119, 145, 151, 154, 156,
      =171= (ii), =256-257= (iii), 261, 279, 286
    arsenic free, 9

  Superphosphate industry, 38, =53= (i), 54, 55, 92, =176= (ii),
      =261-265= (iii)

  Swedish matches, 50, 52, 55, 58, 265


  Tanning, 55, 56, 58, 66, 67, 94, 143, 144, 153, 265, 329

  Tar, 71, 77-80, =96-107= (i), 156, 275, =280-285= (iii)
    colours. See Aniline colours
    derivatives, 40, 46, =96-107= (i), =204-208= (ii), 210, =213-215= (iii)

  Teak wood, 154

  Textile industry, 134, =156= (i), =336= (iii)

  Thermometers, manufacture of, 141, 328

  Tiles, =137-138= (i). See also Pottery

  Tin, 44, 138

  Tobacco industry, =154= (i), =335= (iii)

  Toluene, 32, 35, 96, 108, 112, 204, =206= (ii), 285

  Toluidine, 109, 111, 118, 214, 285, 287

  Treatment of poisoning, =163-127= (ii)

  Turpentine, 69, 104, =215= (ii), 331

  Type casting, 138, 139


  Ultramarine, 19, 22, 259

  Ursol, 118


  Varnish, 58, 61, 101, 215, 330-332, 337

  Vaseline, 60

  Vegetable food stuffs, preparation of, =154= (i), =332-336= (iii)

  Ventilation, =243-255= (iii)
    artificial, 244-247
    localised, 248-250
    natural, 243

  Vermilion, 57

  Vulcanising, 31, =68= (i), 68-70, =272-274= (iii)


  Washing accommodation, =237= (iii)

  Waste sulphuric acid, 43, 53
    water, 66

  Water gas, 82, 84, 87, 88
    gilding, 141, 142, 327

  Weldon process, 23, 29, 58, 59

  White lead, 55, =131-134= (i), =310-313= (iii)

  Wood (poisonous), =154-156= (i), =216= (ii), =335= (iii)

  Workmen’s baths, 237, 292
    clothing, 229
    insurance, 219
    welfare, 237-242


  Xylene, 32, 99, 100, 107, 204, 206


  Zinc, =120= (i), 121, =122-131= (i), 139, 144, 151, =182-183= (ii),
      =294=, 299-305, =323-325= (iii)
    ashes, 125
    oxide, 32, 38, 125, 145, 182
    poisoning, =182-183= (i), =325= (iii)
    smelting, 122-125, =125-131= (i), =323-325= (iii)
    white, 68, 293

THE END

    PRINTED BY
    SPOTTISWOODE AND CO. LTD., COLCHESTER
    LONDON AND ETON





End of Project Gutenberg's Industrial Poisoning, by Joseph Rambousek