HEALTH AND THE LAWS OF MECHANICS 137 



but, as we have intimated, no less interesting. Let 

 us note the following considerations : 



" The doctrine of the specific agent, so brilliantly 

 supported by Trousseau, founded on typhoid fever 

 in the works of Eberth, Gaffky, Chantemesse, and 

 Widal, admits of some modifying circumstances. 



"Microbiology enters upon a new phase in 

 demonstrating the presence in the natural cavities 

 of sound individuals of microbes capable of con- 

 version into pathogenous, such as the microbes of 

 suppuration, pneumonia, and diphtheria. If the 

 investigations of Messieurs Rodet and Roux (of 

 Lyons) are confirmed, that is, if it is shown that 

 Eberth's bacillus is only a modification of the 

 bacillus which habitually lives in the bowel, one 

 cannot consider contact by water as the sole cause 

 of typhoid ; it will be necessary to admit cases in 

 which the bacillus of the bowel has acquired its 

 virulence in the human organism, whilst depending 

 upon modifications in the internal environment. 

 Now, then, is it not well known that excessive 

 fatigue is one of the factors that greatly influence 

 the internal organism? It may be alleged, then, 

 that an individual undergoes, under the influence 

 of auto-intoxication from excessive fatigue, such 

 modifications that at any given moment he may 

 become a victim to the Bacterium coli. Thus 

 would be explained the different morbous series 



