RELATION TO INFECTIOUS DISEASES. 85 



CHARRIN and ROGER have shown that white rats, 

 which are naturally immune to anthrax, IM-COIUC susceptible 

 when fatigued by Ix-ing kept on a small tread-mill. Klcve-n 

 rats were inoculated with an anthrax culture; five of these 

 which were allowed to rest in the cage manifested no symp- 

 toms of the disease, while six which were placed on the 

 tread-mill developed the disease and died within from 

 twenty-four to thirty hours. The bacilli were found in 

 the liver and spleen of those which died; and guinea-pigs 

 inoculated with these germs died. The influence of the 

 condition of health on susceptibility to the infw-tious dis- 

 eases has also been shown by LEO, who found that mice 

 which arc- naturally insusceptible to glanders, become highly 

 <:i-!-cptible when they are rendered diabetic by the adminis- 

 tration of phloridzin. 



That some- neurotic art'e-ctions originate from traumatism 

 we know. That others of this class are largely due to mal- 

 nutrition accompanied by improper metabolism or insuffi- 

 cient elimination, or, in other words, are to some extent 

 autogenous, all l>elieve. Understanding, then, that the 

 alove classification docs not attempt a sharp and marked 

 differentiation of the causes of disease, we will now give 

 our attention to a consideration of the chemical factors in 

 the causation of the infectious diseases, and of the trau- 

 matic, autogenous and neurotic, in so far as these are influ- 

 enced by infection. 



Recognizing the fact that germs do l>ear a e-ausal relation 

 to some diseases, the question arises, How do these organ- 

 isms product- disease? In what way does the bacillus 

 anthracis, for instance, induce the symptoms of the disease 

 and death? Many answers to this question have been 

 oH'ere-d. Sinie of the most important of these are as fol- 

 lows : 



1. It was first suggested by BOLLINGER that apoplecti- 

 form anthrax is due- to deoxidation of the blood by the 

 bacilli. These germs are aerobic-, and were supposed to 

 deprive the rc.nl blood-corpuscles of their oxygen. This 

 theory was suggested most probably by the resemblance of 

 the symptoms to those of carbonic acid pcrsoning. The 



