260 BACTERIOLOGY. 



example, ergot is a local growth for the grain, 

 a poison for man. 



In all cases, from the simple germs of putre- 

 faction and the ceco-parasites up to the obliga- 

 tory parasites, one thing is a pre-requisite to 

 successful invasion, namely, that as compared 

 with the mechanical or chemical attacking 

 powers of the microbe the mechanical and 

 chemical resisting powers of man be relatively 

 feeble or impaired. If this is not the case the 

 human organism either does not allow the germ 

 to gain entrance to the body, or when entrance 

 is effected it nullifies the poisonous action by 

 a counteraction. 



After what has now been stated no particular 

 assurance is necessary that bacteria and other 

 minute pathogenic organisms do not exercise 

 their injurious effect upon man from an inbred 

 wickedness and pleasure in doing mischief, but 

 that in the phenomena of parasitism we have 

 to do simply with questions of adaptation, with 

 the utilization of situations, so to speak, which 

 man himself provides by his own sins of hy- 

 gienic omission and commission, and which 

 therefore he himself is able to remove. The 

 germs of putrefaction dispose of the dead bodies 

 of all organisms in nature, simply to satisfy 

 their own need of energy and the conditions 

 of their own metabolism. This is also the case 



