142 ANTHRAX. 



must give rise to the same symptoms and changes found in 

 the animal originally affected, and the same bacteria must be 

 found in their blood, tissues, or secretions. 



Morphology. The anthrax bacillus is a rod bacterium 

 measuring from 2 to 3 mikrons when found in the blood and 



FIG. 53. 



Bacillus anthracis, highly magnified to show swellings and concavities at extremities 

 of the single cells. (Abbott.) 



tissues of animals ; from 20 to 25 mikrons when obtained 

 from cultures; and of a uniform thickness of 1.25 mikrons. 

 The ends of the rod seem a little thicker than the rest of the 

 body, and under a low power look square, but with a higher 

 power they are seen to be concave (Fig. 53). 



FIG. 54. 



Threads of Bacillus anthracis containing spores. X about 1200. (Abbott.) 



It is found singly or in pairs in the blood and tissues of 

 diseased animals, but when cultivated in bouillon or in the 

 hanging drop it forms long threads which may or may not 

 contain spores. 



It is stained by all the alkaline auilin dyes, the spores 



