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.