378 



CHOLERA. 



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. 93). 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 ob- 

 tained at different 

 places have shown 

 considerable varia- 

 tions in this respect. 

 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 " arthrospores," but 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. Some are irregularly twisted filaments, some- 

 times globose, sometimes clubbed at their extremities, 

 and also showing irregular swellings along their course. 

 Others are short and thick, and may have the appearance 



FIG. 93. Cholera spirilla stained to show 

 the terminal flagella. x 1000. 



