The Comma Bacillus 607 



cation by fission progresses with rapidity; but when ad- 

 verse conditions arise, long spiral threads unmistak- 

 able spirilla develop. Frankel found that the exposure 

 of the cultures to unusually high temperatures, the addition 

 of small amounts of alcohol to the culture-media, and other 

 unfavorable conditions lead to the production of spirals 

 instead of "commas." 



The cholera spirilla are actively motile, and in hanging- 

 drop preparations can be seen to swim about with great 

 rapidity. Both comma- shaped and spiral organisms move 

 with a rapid rotary motion. 



The presence of flagella can be demonstrated without 



*&**** 



#rk '.. 



Coa* <i. t \ 



s*-* ;%% 



Fig. 209. Spirillum of Asiatic cholera, from a bouillon culture three 

 weeks old, showing long spirals. X 1000 (Frankel and Pfeiffer). 



difficulty. Each spirillum possesses a single nagellum 

 attached to one end (spiromonas). 



Involution-forms of bizarre appearance are common in 

 old cultures of the spirillum, and sometimes in fresh cultures 

 many individuals show by granular cytoplasm and irregular 

 outline that they are degenerated. Cholera spirilla from 

 various sources differ in the extent of involution. 



In partially degenerated cultures containing long spirals 

 Hiippe observed, by examination in the "hanging-drop," 

 certain large spheric bodies which he described as spores 

 (arthrospores). Koch and, indeed, all other observers fail 



