THE STORY OF THE BACTERIA. 69 



The effects which these as well as other dis- 

 ease-producing bacteria may produce in the 

 body vary considerably under different condi- 

 tions. Sometimes the general condition of the 

 body is such that it seems to furnish very 

 favorable soil for their proliferation or is espe- 

 cially vulnerable to their action. Sometimes 

 the particular germs which gain access seem to 

 be especially virulent, perhaps from their inhe- 

 rent vigor or from conditions which we know 

 nothing about. We are in these diseases deal- 

 ing with poisons of the human body, but with 

 self-propagating poisons which from an almost 

 infinitesimal amount may grow to such quanti- 

 ties as will fairly overwhelm the body. 



