DESCRIPTIONS OF PATHOGENIC BACTERIA. 155 



influence upon temperature is of secondary 

 importance. 



Some ten or twelve years ago it was perfectly 

 easy to describe and define disease-producing 

 bacteria. In the state of our knowledge at 

 that time it could be said, for example, that 

 anthrax bacilli are microbes which always 

 occur in typical situations in the organism af- 

 fected by anthrax, and which on being trans- 

 ferred to another organism can again cause 

 anthrax. To-day we know that only the first 

 of these statements is even approximately cor- 

 rect. As regards the transfer to another or- 

 ganism, one might almost as well say that an- 

 thrax bacteria do not cause anthrax, a paradox 

 which may be explained very simply. The 

 virulence of the bacteria fluctuates greatly and 

 it is this fact that renders dubious the issue of 

 many inoculation experiments. I shall dis- 

 cuss these questions later, but it seems advisr 

 able to mention them now in order to emphasize 

 the scientific inadequacy of the conventional 

 schematic representations according to which 

 specific bacteria are regarded as the " cause " 

 of specific diseases. 



In direct relation to the intoxications pro- 

 duced by poisons formed outside of the body 

 and introduced into it, stand the septicaemia, 

 pysemic, phlegmonous and erysipelatous pro- 



