586 BACTERIOLOGY. 



many other observers have reported finding varieties of 

 the comma bacillus. Only a few of these can be here 

 mentioned, of which there is any certainty that they 

 were derived from true cholera cases. Thus Friedreich 

 has accurately described and photographed a series of 

 forms which, however, vary but little from the original 

 type. But more interesting than the reports of varie- 

 ties are the observations of the variability of the cholera 

 bacillus. Claussen, in Esmarch' s institute, isolated from 

 fresh cholera stools vibrios which presented in plate 

 cultures a different appearance of the colonies, which 

 showed a tendency to disintegrate and having an irreg- 

 ular border. The nitrosoindol reaction was absent; 

 bouillon cultures were non-pathogenic to guinea-pigs, 

 and stick cultures grew slowly and uncharacteristically. 

 On repeated inoculation, however, a guinea-pig died 

 after the injection of 1 c.c. of a bouillon culture; in 

 the peritoneal exudate and even in the blood character- 

 istic bacilli were found and the cultures gave the indol 

 reaction. Celli and Santori, in Rome (1893), isolated 

 from the stools of many typical cholera cases a vibrio 

 which they called vibrio romanus, which was non-patho- 

 genic for animals, gave no indol reaction, did not coag- 

 ulate milk, and at 37 C. grew neither in bouillon nor 

 on agar. After cultivation for nine months it gave the 

 indol reaction and grew at 37 C., but was still almost 

 non-pathogenic. Bordoni-Uffreduzzi and Abb culti- 

 vated from a typical cholera case a short vibrio which 

 liquefied gelatin very rapidly and presented an abnor- 

 mal growth, and gave a yellow growth on potato, but 

 which on continued cultivation became more and more 

 like the cholera spirillum. Variations even greater than 

 occur in these varieties of cholera spirilla are met with 

 among diphtheria bacilli. 



