THE CHOLERA SPIRILLUM. 



405 



a large number of turns. If film preparations be made 

 from the intestinal contents in typical cases, it will be 

 found that these organisms are present in enormous 

 numbers in almost pure culture, and that most of the 

 spirilla lie with their long axis in the same direction, so 

 as to give the appearance which Koch compared to a 

 number 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 

 flagellum is present 

 at one end only 

 (Fig. 105). It is very 

 delicate, and measures 

 four or five times 

 the length of the 

 organism. In some 

 varieties, however, 

 there may be such 

 a flagellum at both 

 ends, and again, 

 more than one may 

 be present. Cultures 

 obtained at different 

 places have shown 

 considerable varia- 

 tions in this respect. 

 Cholera spirilla do not form spores. In old cultures, how- 

 ever, small rounded and highly refractile bodies may be 

 found in the organisms, which have been regarded by 

 Hueppe as " arthrospores," but which are in reality merely 

 the result of degeneration, as they have no higher powers 

 of resistance than the spirilla themselves, and cultures 

 containing enormous numbers of such bodies may be 

 found to be quite dead. Along with such appearances 

 in old cultures there is found great change in the 

 size and shape of the organisms (Fig. 106). Some are 

 irregularly twisted filaments, sometimes globose, sometimes 



FIG. 105. Cholera spirilla stained to show 

 the terminal flagella. x 1000. 



