146 BACTERIOLOGY. 



is so essential to the life of the tissues. But this 

 would hardly account for so acute and fatal a result 

 as anthrax, but would lead one to expect symptoms 

 of inanition and gradual exhaustion. Moreover 

 against this theory we have the fact that death 

 may result, for example, from anthrax, with the 

 occasional presence of comparatively few bacilli; 

 and again, the blood may teem with parasites 

 such as the flagellated monads in well-nourished, 

 healthy-looking rats, without apparently causing 

 any symptoms whatever. In the same category 

 may be placed the theory that eminently aerobic 

 organisms seize upon the oxygen of the blood 

 and produce death by asphyxia. Another explana- 

 tion is afforded by the suggestion of interference 

 with the functions of the lung and kidney by mecha- 

 nical blocking of the capillaries. Here the same 

 objection is met with in the case of anthrax, 

 the same fatal result may occur with only a few 

 bacilli, while other cases yield very beautiful 

 sections, looking like injected preparations from 

 the mapping out of the capillaries with the count- 

 less crowds of bacilli (Plates XVI. and XVII.) 



The most satisfactory explanation is probably 

 afforded by analogy with the putrefactive bacteria. 

 We have seen that they derive their necessary 

 elements from complex organic substances, and 

 accompanying the residue we find the presence of 

 poisonous alkaloids. Do pathogenic bacteria act 

 in the same way? Does the anthrax bacillus 



