BACILLUS ANTHRACIS. 413 



1 to 1.25 /JL. Frequently very long threads made up of 

 several rods, joined end to end, are seen. 



When obtained directly from the body of an animal 

 it is usually in the form of short rods square at the ends. 

 If highly magnified, the ends are seen to be a trifle 

 thicker than the body of the cell and somewhat indented 

 or concave, peculiarities that help to distinguish it from 

 certain other organisms that are somewhat like it mor- 

 phologically. (See Fig. 87.) 



FIG. 87. 



Bacillus anlhracis highly magnified to show swellings and concavities 

 at extremities of the single cells. 



When cultivated artificially at the temperature of the 

 body the bacillus of anthrax presents a series of very 

 interesting stages. 



The short rods develop into long threads, which may 

 be seen twisted or plaited together after the manner of 

 ropes, each thread being marked by the points of junc- 

 ture of the short rods composing it. (Fig. 88, a and 6.) 



In this condition it remains until alterations in its 

 surroundings, the most conspicuous being diminution in 

 its nutritive supply, favor the production of spores. 

 When this stage begins, changes in the protoplasm of 

 the bacilli may be noticed; they become marked by 

 irregular, granular bodies, which eventually coalesce into 

 glistening, oval spores, one of which lies in nearly every 



