192 INFECTIVE DISEASES. 



Within the last few years u great change of ojainion has taken 

 place. Bacteriologists have investigated the whole subject, so that 

 at the present day we know exactly the cause of anthrax. 



Bacillus anthracis {Bacterldie du. charbon, Bacillus of splenic 

 fever, Wool-sorters' disease, or malignant pustule). — Rods 5 to 20 /i 

 long and 1 to 1-25 ;u. broad, and threads; spore-formation present. 

 As a thorough knowledge of the life-history of this bacillus is of the 

 greatest importance, the various steps to be followed in a practical 

 study of it will be successively treated in detail. Its morphological 



'^''^r^ 



Fig. 92.— Bacillus Anthkacis, /. 1200. Blood corpuscles and bacilli 

 unstained ; from an inoculated mouse (Fkankel and Pfeiffee). 



and biological characteiistics liave been very completely worked out, 

 and it serves as an excellent subject foi' gaining an acquaintance 

 • with most of the methods employed in studying micro-organisms. 



A mouse inoculated with the bacillus or its sjDores will die in 

 from twenty-four to forty-eight houi's, oi' more rarely in from 

 forty-eight to about sixty hours. 



Examination after Deatli. — The spleen is found to be considerably 

 enlarged, and may be removed, and examined by making cover-glass 

 preparations, inoculations in nutrient media, and subsequently 

 sections. 



Vorer-ijlass Preparations. — In cover-glass preparations of the 

 blood of the spleen the liacilli are found in enormous numbers. 

 Pi'eparations should also be made with blood from the heart and 

 witli the exudation from the lungs and other organs ; it will be 



