CHAPTEE XXIV. 



study of bacillus anthracis, and the effects produced by its inoculation 

 into animals— Peculiarities of the organism under varying conditions of sur- 

 roundings. 



The discovery that the blood of animals suffering 

 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 micro-organism, now known as baeillus an- 

 thracis, is always present in the blood of animals suffer- 

 ing from this disease; that this organism can be obtained 

 from the tissues of these animals in pure cultures, and 

 that these artificial cultures of bacillus anthracis when 

 introduced into the body of susceptible animals can 

 again produce a condition identical with that found in 

 the animal from which they were obtained. 



The disease is a true septicsemia, and after death the 

 capillaries throughout the body will always be found to 

 contain the typical rod-shaped organism in larger or 

 smaller numbers. 



This organism, when isolated in pure culture, is seen 

 to be a bacillus which varies considerably in its length, 

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

 threads of 20 to 25 /i in length. In breadth it is from 



