THE TUBERCLE BACILLUS 601 



to sister, 19 from mother to child, 16 from other relatives, and in 33 cases 

 it was traced to people who were not relations, but with whom the 

 patient had been in communication. He also quotes Zasetsky who 

 reports the case of a tuberculous woman who, in the course of eleven 

 years married three husbands who had been previously healthy. The 

 first one died of tuberculosis seven years after marriage, the second three 

 years later, and the third at the time of the report had the disease, the 

 wife in the meantime having died of tuberculosis. 



The fact that tubercle bacilli may be conveyed in dust has been 

 indicated above, but there are other means by which habitual 

 inhalation of dust may favor the spread of tuberculosis, namely, 

 by virtue of the irritant properties of inhaled dust in predisposing 

 the lung to infection. Attention to the dangers of trades in which 

 dust is an habitual environmental factor has been particularly empha- 

 sized by Winslow and Greenberg. Sommerfeld, whom we quote from 

 Kober, made a statistical study in which he showed that in the 

 population of Berlin, the average tuberculosis death rate was 4.93 

 per 1000. The rate in the non-dusty trades, was 2.39, and in the 

 dusty trades 5.2. He also states that the analysis of tuberculosis in 

 the towns in Vermont where granite and marble cutting is carried 

 out showed a tuberculosis rate of 2.2 per 1000 against a rate of 1.3 

 for the whole state, and Ropke is stated by the same writer to have 

 shown that the mortality from tuberculosis of the population in the 

 large cutlery center, Solingen, in Germany was reduced from 5.4 

 per 1000 in 1885, to 1.8 in 1910, by measures aimed at the control 

 of the dust in work rooms. A recent study by Drury 35 shows that 

 polishers and grinders in axe factories are subject to a death rate from 

 pulmonary tuberculosis considerably above that of others in the same 

 mill. In the two decades from 1900 to 1919, the polishers and grinders 

 showed a death rate of 19 per 1000 as against 6.5 of the entire mill 

 population, and between 1 and 2.4 of the general population of the 

 district. 



In regard to the predisposing factors to tuberculous infection, many 

 phases enter into the problem in this disease which exert a much less 

 direct or perhaps negligible influence in connection with other infections. 

 There can be no question about the fact that poverty, with its coincident 

 crowding in living quarters, close personal contact at night, insufficient 

 warmth, and particularly undernutrition and low fat diet, play a role 



35 Drury, Pub. Health Reeports, U. S. P. H. S., Feb., 1921, Vol. 36, No. 5. 



