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.