VIBRIO PROTEUS: CULTURAL PECULIARITIES. 341 



middle than at the poles ; it forms, like the " comma 

 bacillus," screw-like, twisted threads (Fig. 64). 



It is supplied with a single flagellum at one of its ends, 

 and is, therefore, motile. 



It, like the comma bacillus, readily undergoes degener- 

 ative changes under conditions unfavorable to growth 

 and presents the variety of shapes grouped under the 

 head "involution forms." According to Buchner this 

 is especially the case when the medium in which they 

 are growing contains glucose (5 per cent.) or glycerin 

 (2 per cent.). 



Fig. 64. 



iff' ' {cV 

 — ,-' /■ 



Vibro proteus, Plnkler-Prior bacillus, from culture on agar-agar twenty- 

 four hours old. 



Cultural Pbculiakities. — On gelatin plates the 

 development of its colonies is far more rapid, and 

 liquefaction much more extensive, than in the case of 

 the cholera spirillum. After twenty-two to twenty- 

 four hours in this medium at 20° to 22° C. the average 

 size of the colonies is about double that of the comma 

 bacillus. The colonies are darker and denser and do 

 not present under the low lens the same degree of 

 granulation and subsequent lobulation, and they do not 

 become serrated or scalloped around the margin as is 

 the case with Koch's organism. After twenty-two to 

 twenty-four hours they are usually nearly round, regu- 

 larly granular,' and more or less sharply defined. (See 



