358 BACTERIOLOGY. 



from 1 to 1.25 fi. 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 in- 

 dented or concave, peculiarities that help to distinguish 

 it from certain other organisms that are somewhat like 

 it morphologically. (See Fig. 76.) 



Fig. 76. 



A 



Bacillus anthraeis 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. 77, a and b.) 



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 



