SYMPTOMATIC ANTHRAX. 153 



point of inoculation, involving also the muscular tissues. 

 The internal organs show little change, excepting the spleen, 

 which is enlarged. The bacilli are rarely found in the blood 

 of the heart when the autopsy is performed immediately 

 after death, but they are found in limited numbers in the 

 internal viscera. If the autopsy is delayed, however, the 

 whole body of the animal becomes infected with the bacillus. 

 This bacillus is grown, like the tetanus and other anaerobics, 

 in atmospheres of hydrogen only. 



SYMPTOMATIC ANTHRAX. 

 Bacillus Anthracis Symptomatici. 



History. Ferrer and Bellinger discovered a bacillus in the 

 disease of animals known as black leg, quarter evil, or quarter 

 ill, which is also found in humid soils in certain localities 

 during the summer months, especially when those places have 

 been contaminated with discharges from infected animals. 



Morphology. The description of this microorganism given 

 by Kitasato is as follows : 



Actively motile rods, 3 to 5 mikrons in length, and from 

 0.5 to 0.6 mikron in thickness, occurring singly, occasionally 

 in pairs, never forming filaments (Fig. 62). 



It stains by all the anilin colors and by Gram's method. 

 It forms spores, which are situated at or near one of the poles, 

 giving a swollen appearance to the bacillus. 



Biologic Characters. In the vegetative type it is actively 

 motile, but loses its motion in the spore-bearing form. It 

 can not be cultivated in an atmosphere of oxygen. It is 

 purely anaerobic, and does not grow in an atmosphere of car- 

 bonic acid gas. 



It grows best when glucose (1.5 to 2 per cent.) or glyc- 

 erin (4 to 5 per cent.) is added to the culture-medium. It 

 grows in all media. It liquefies gelatin. It grows best 

 at the temperature of the incubator, 37 C., but does not 

 grow at a temperature below 14 C. In deep-seated punct- 

 ures of gelatin or agar it grows in three or four days, and 

 produces during its growth gas bubbles. The colonies appear 



