196 MARRIAGE AND DISEASE. 



world, and had the effect of greatly unsettling opinion 

 upon tubercular disease generally. This was to be 

 expected, for what had been looked upon for ages as 

 one of the most hereditary of all diseases, was suddenly 

 proved to be a contagious disease, which could be con- 

 veyed from person to person, like small-pox or scarlet 

 fever, and doubt at once arose as to whether hereditary 

 predisposition had anything whatever to do with the 

 spread of the disease. This doubt was fostered by 

 the discovery that the sources of infection were almost 

 innumerable. It was shown that the disease might 

 be conveyed by eating the flesh of animals suffering 

 from the disease, or by drinking the milk of such; 

 and as it was known that a great number of cattle 

 were tubercular, it was evident that here alone was 

 a great and constant source of contagion. It was 

 further pointed out that the sputa of persons suffering 

 from phthisis contain myriads of bacilli, and as such 

 persons are constantly coughing and spitting, there 

 must be grave danger to all who live with, work 

 with, or have intimate relations with, such persons. 

 Nor did the danger of infection from phthisical 

 persons stop eyen here, for it was asserted that this 

 bacillus-laden sputum, after it had become hard and 

 dry, might be broken up, to float as minute particles 

 in the air, and be inhaled by any one breathing the 

 contaminated atmosphere, the bacilli in such dried 

 sputum retaining sufficient vitality to set up tuber- 

 cular disease in the person inhaling it. In fact, the 

 disease germ was almost ubiquitous, which fact alone 



