EPIDEMIOLOGY OF TUBERCULOSIS KOCH. 



663 



The question, therefore, arises as to what is the cause, or rather 

 what are the causes of this decrease, for it can hardly be supposed 

 that it depends on a single factor alone. 



Concerning this it might at first be supposed that the death rate 

 from consumption decreases because the general death rate, as is well 

 Imown, is also decreasing. This need not necessarily be so, for it 

 would only occur in case the causes which influence the general death 



Table 2. — Mortality from consumption in rrussia. 



n. 





ri:Li_Lr;Liriinn;jlLl 



j^?f"W 



? 3 N 5 t ? S'aA'i 3 S 5 6 fs'w S 3 1 5 1 IT? 



rti 



w 



rate have a similar influence upon the death rate from consumption. 

 But we now see that the decrease in the latter is much more rapid than 

 that of the general mortality, this being more probably influenced in 

 a considerable degree by the decrease in pulmonaiy consumption. 

 Therefore that disorder must be influenced by factors peculiar to 

 itself. 



It might also appear possible that the decrease in tuberculosis 

 depends upon the general epidemiological course of this disease ; that 



