THE CHOLERA SPIRILLUM. 409 



cases, it will be found that these organisms are present in enor- 

 mous numbers in almost pure culture, and that most of the spi- 

 rilla lie with their long axes in 

 the same direction, so as to 

 give the appearance which 

 Koch compared to a school of 

 fish in a stream. 



They possess very active 

 motility, which is most marked 

 in the single forms. When 

 stained by the suitable methods 

 they are seen to be flagellated. 

 Usually a single terminal flagel- 

 lum is present at one end only 



(Fig. I 39). It is Very delicate, FlG . 13 g. _ cholera spirilla, from a culture 



and measures four or five times of a ar of twenty-four hours' growth. 



,_, , i r i Stained with weak carbol-fuchsin. X 1000. 



the length of the organism. In 



some varieties, however, there may be a flagellum at both ends, 

 or more than one may be present ; cultures obtained at differ- 

 ent places have shown considerable variations in this respect. 







% 



' *% 



FlG. 139. Cholera spirilla stained to FlG. 140. Cholera spirilla from an old 



show the terminal flagella. X 1000. agar culture, showing irregularities in size 



and shape, with numerous faintly stained 

 coccoid bodies involution forms. 

 Stained with fuchsin. X 1000. 



Cholera spirilla do not form spores. In old cultures, however, 

 small, rounded, and highly refractile bodies may be found in the 

 organisms, which have been regarded by Hueppe as "arthro- 

 spores," but which are in reality merely the result of degenera- 



