Morphology 449 



exposure of the cultures to unusually high temperatures, 

 the addition of small amounts of alcohol to the culture 

 media, and other unfavorable conditions favored the pro- 

 duction of spirals instead of "commas." One of the most 

 common forms is that in which two short curved individuals 

 are conjoined in an S-shaped curve. 



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 





Fig. 130. Spirillum of Asiatic cholera, from a bouillon culture three 

 weeks old, showing long spirals. X 1Q 00 (Frankel and Pfeiffer). 



difficulty. Bach spirillum possesses a single flagellum 

 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 



2Q 



