CHAPTER XXIII. 



Study of tlie bacillus of anthrax, and the effects produced by its 

 inoculation into animals — Peculiarities of the organism under 

 varying conditions of surroundings. 



The discovery that the blood of animals suflering 

 from splenic fever, or anthrax, always contained minute 

 rod shaped bodies (PoUender, 1855; Davaine, 1863), 

 led to a closer study of this disease, and has resulted, 

 probably, in contributing more to our knowledge of 

 bacteriology in general than work upon any of the 

 other infectious maladies. 



The outcome of these investigations is that a rod- 

 shaped microorganism, now known as the bacillus of 

 anthrax, is always present in the blood of animals suf- 

 fering from this disease; that this organism can be ob- 

 tained from the tissues of these animals in pure cultures, 

 and that these artificial cultures of the bacillus of anthrax 

 when introduced into the body of susceptible animals 

 can again produce a condition identical to that found in 

 the animal from which they were obtained. 



The disease is a true septicaemia, and the capillaries 

 throughout the body after death will always be found 

 to contain the typical rod-shaped organism in larger or 

 smaller numbers. 



This organism, when isolated in pure cultures, is seen 

 to be a bacillus which varies considerably in its length, 

 ranging from short rods of 2 to 3 /^ in length to longer 

 rods of 20 to 25 n in length. In breadth it is from 1 



