668 ANNUAL. REPORT SMITHSONIAN INSTITUTION, 1910. 



regular, uniform decrease in mortality from consumption, and that 

 we must therefore seek for other factors than those dependent on a 

 spontaneous cause of decrease connected with the epidemiological 

 course of the disease. 



Table 7. — Mortality from consumption at Berlin. 



It might be alleged that the virulence of tuberculosis has abated. 

 But in reply to this it should be said first that the decrease in tuber- 

 culosis began quite suddenly, and after a feAV decenniums has 

 reached, in many cases, 50 per cent and over. As the mortality from 



