BACILLUS ANTHRACIS 



IN 1850 Davaine and Rayer observed that anon- 

 motile bacillus was constantly to be found in the 

 blood of animals which died of anthrax, and this 

 observation was extended by Brauell in 1857 to the 

 disease as it occurred in man. From 1863 onwards 

 Davaine sought to prove that this bacillus was the 

 cause of the disease, but it was Koch who, in 1876, 

 furnished this proof, and it is to him that we owe 

 our knowledge of the complete life cycle, including 

 the spore- bearing stage, of the specific micro- 

 organism. The study of the physiology of the 

 bacillus, especially with regard to the possibility of 

 obtaining cultures of attenuated virulence, and the 

 use of such cultures as preventive vaccines, is in 

 great part the work of Pasteur and his pupils. The 

 appearance of the bacillus as it is met with in the 

 blood of an animal dead of anthrax is shown in 

 Fig. 15. It is a non- motile, rod-shaped organism, 

 3-5 fj. in length and 1-1*5 /n in width, occurring 



