444 HUMAN BIOLOGY 



actively tuberculous fathers. Numerous associations, such as 

 the American National Tuberculosis Association organized 

 by«=E. L. Trudeau in 1904 and the National Association for the 

 Prevention of Tuberculosis founded in Great Britain in 1898, 

 have undertaken antituberculosis campaigns for the education 

 of the public so as to prevent infection and, if this has already 

 occurred, to popularize treatment at the earliest possible 

 time; by way of propaganda they have arranged travelling 

 exhibits, lectures, and cinema films, such as that of the 

 American National Tuberculosis Association which toured 

 all the States east of the Mississippi from 1906 to 19 12. 

 It is satisfactory to notice that the death rate from tuberculo- 

 sis in the United States, which was 201 per 100,000 in 1900, 

 has been reduced to 86.6 in 1925. These campaigns, especially 

 by their insistence on the gospel of open-air, have also led, 

 as a kind of by-product, to improvement in the general 

 health of the human race. 



In 1882 Robert Koch demonstrated the microorganism, 

 the tubercle bacillus, responsible for widespread disability 

 and death, and thus opened the way to the prevention of 

 infection, both from human and animal sufferers, for example 

 by inhalation of the expectoration and by ingestion of milk 

 containing bovine bacilli. Thus the spread of "the seed" can 

 be minimized by education of the public, laws against spitting, 

 and special care and measures to be taken about those 

 with the fully developed disease, such as destruction of 

 their expectoration, efficient ventilation and disinfection. 

 The importance of preventing the spread of tuberculosis 

 by milk from cows suffering from the disease has already 

 been mentioned. Without "the seed," or the tubercle 

 bacillus, the disease of course cannot occur, but it is so 

 ubiquitous that in towns avoidance of exposure to its 

 infection cannot be insured, and yet it is comparatively 

 few who fall victims to its obviously evil effects. The factor 

 of the "soil" or constitutional power of resistance of the 

 individual was somewhat cast into the background in the early 

 days of bacteriology when much was hoped from the dis- 

 covery of the responsible germ and specific treatment by 

 tuberculin; but its importance is now fully recognized in the 

 hygiene and open-air methods of treatment and in the care of 



