258 PATHOGENIC BACTERIA. 



itself so as to assume the form of a fragment of a tape- 

 worm. Upon agar-agar after the lapse of two days the 

 growth consists of a central pellicle along the line of in- 

 oculation, with little sprouts projecting in all directions 

 from the edges. The growth is grayish, with an occa- 

 sional yellowish tinge. 



Punctures in agar-agar were unsuccessful, but in gela- 

 tin the appearance of the growth is similar to that of 

 the cholera spirillum. 



The bacillus also grows upon potato in the form of an 

 elevated layer of exactly the same color as the potato. 

 In the course of time the entire potato becomes colored 

 a dark gray. It also grows in milk, urine, serum, and 

 water. 



The colonies of this bacillus are quite characteristic, 

 but so varied in appearance as to make one suspect that 

 the plate upon which which they grow is contaminated 

 with various other species of bacteria. In general, the 

 colonies may be said to appear slowly as transparent 

 whitish drops, which become grayish and later yellow- 

 ish, and finally brownish in color. The gelatin about 

 them presents concentric, wave-like rings, depending 

 upon the liquefaction of the medicine. 



When the growth is more rapid and occurs at higher 

 temperatures bundles of threads, somewhat resembling 

 the early stages of a mould, are observed. Examining 

 microscopically, one finds in the slowly growing colonies 

 a surrounding zone of small centrifugally arranged fine 

 threads or hairs extending in all directions, with one or 

 two exceptionally long bundles extending beyond the 

 others and beyond the limits of the colony. The long 

 threads are never found to divide. Many of the colonies 

 are highly suggestive of those of anthrax. 



The bacillus is motile in very slight degree. It forms 

 spores. It is, in general, about the size of the tubercle 

 bacillus. 



The vegetation of the organism is said to be peculiar 

 in that the bacillary stage is of short duration and soon 



