SYSTEMATIC AND DESCRIPTIVE. 149 



in a practical study of it will be successively treated 

 in detail. Its morphological and biological charac- 

 teristics have been very completely worked out, 

 and it serves as an excellent subject for gaining 

 an acquaintance with the various methods that 

 should be employed in studying micro-organisms. 

 It is found that a mouse inoculated with the bacillus 

 or its spores will die in from twenty- four to forty- 

 eight hours, or more rarely in from forty-eight to 

 about sixty hours. 



Examination after death. The details to be ob- 

 served in the autopsy have already been described 

 (p. . 96). The spleen is found to be consider- 

 ably enlarged, and may be removed (p. 97), and 

 examined by making cover-glass preparations, 

 inoculations, and subsequently sections. 



Cover -glass-preparations. In cover-glass-prepara- 

 tions of the blood of the spleen the bacilli are found 

 in enormous numbers. Preparations should be 

 made similarly with blood from the heart and exuda- 

 tions from the lungs, etc. In the last-mentioned the 

 bacilli are present in very small numbers, or alto- 

 gether absent They should be examined both un- 

 stained and stained (p. 46). The rods are straight, 

 or sometimes curved, rigid, and motionless, and vary 

 in size in different animals. They stain intensely 

 with aniline dyes, and are then seen to be composed 

 of segments with their extremities truncated at right 

 angles ; between the segments a clear linear space 

 exists, which is typically characteristic (Plate I., 



