276 ANTHRAX, 



In his earlier experiments he failed to produce death by 

 feeding susceptible animals on either bacilli or spores, and 

 as the intestinal tract was, in his view, the natural path of 

 infection, he considered as incomplete the proof of this 

 method of the rise of anthrax spontaneously in herds 

 of animals. Koch's observations were, shortly afterwards, 

 confirmed in the main by Pasteur, though controversy arose 

 between them on certain minor points. Moreover, furthe 

 research showed that the disease could be produced in 

 animals by feeding them with spores, and thus the way in 

 which the disease might spread naturally was explained. 



The chief critic of Koch's work was Buchner, who 

 stated that in the course of generations the B. anthraci 

 became transformed into the bacillus subtilis, and also tha 

 the B. subtilis could by suitable precautions be transformec 

 into the B. anthracis. These observations are now known 

 to be quite erroneous, and possess no more than a historic 

 interest. 



Anthrax as a disease in man is of comparative rarity 

 Not only, however, is the bacillus anthracis easy of growth 

 and recognition, but in its growth it illustrates many o 

 the general morphological characters of the whole group o 

 bacilli, and is therefore of the greatest use to the student 

 Further, its behaviour when inoculated in animals illustrates 

 many of the points raised in connection with such difficul 

 questions as the general pathogenic effects of bacteria 

 immunity, etc. Hence an enormous amount of work has 

 been done in investigating it in all its aspects. 



The Bacillus Anthracis. If a drop of blood is taken 

 immediately after death from an auricular vein of a cow 

 for example, which has died from anthrax, and examinee 

 microscopically, it will be found to contain a great number 

 of large non-motile bacilli. On making a cover-glass pre 

 paration from the same source, and staining with watery 

 methylene-blue, the characters of the bacilli can be better 

 made out. They are about 1.2 //, thick or a little thicker 

 and 6 to 8 //, long, though both shorter and longer forms 

 also occur. The ends are sharply cut across, or may be 



