VIBRIO CHOLERA. 365 



by Friedrich (A. G. A. vin, 87), yet they do not deviate very widely 

 from the typical organism. 



More interesting than the reports regarding varieties are 

 the observations regarding variability : 



For example, the experiments made by Claussen in v. Esmarch's 

 institute are very instructive. Vibrios freshly isolated from cholera 

 stools presented upon plates a tendency for the colony to disintegrate 

 and exhibit a border as if eaten away. The nitroso-indol reaction was 

 absent. A guinea-pig did not* die after the injection of 1 c.c. of a 

 bouillon culture. The stab cultures grew slowly and were not char- 

 acteristic. After repeated transfers in bouillon, a guinea-pig died after 

 the injection of 1 c.c. of the bouillon, and in the peritoneal exudate, 

 and even in the blood, cholera vibrios were found which possessed all 

 the characteristic peculiarities, including the nitroso-indol reaction 

 (C. B. xvi, 325). 



Vibrio romanus of Celli and Santori, isolated from numerous 

 typical cases of cholera in Rome in 1893, was cultivated from the 

 stool, was not pathogenic for animals, gave no indol reaction, did not 

 coagulate milk, and at 37 grew neither in bouillon nor on agar. 

 After being culvtiated for eight months it gave the indol reaction and 

 grew at 37, but was still almost perfectly non-pathogenic (C. B. xv, 

 789). 



Bordoni-Uffreduzzi and Abba cultivated from a typical case of 

 cholera a very rapidly liquefying, short vibrio, which grew atypically 

 upon gelatin and formed a yellow growth upon potato. After being 

 cultivated for nine months upon gelatin it was constantly like the 

 cholera vibrio, both macroscopically and microscopically (C. B. xvi, 

 201). 



The Varieties Most Closely Related to the Cholera 

 Vibrio. 



When the cholera vibrio was discovered, its peculiarities 

 seemed so characteristic that its differentiation from other 

 bacteria was thought to be easy. Since then there have 

 been found in the environs of man first a few, then more, 

 and finally such an immeasurable series of vibrios that 

 for a long time they have no longer been designated by 

 separate names. The richest results have been yielded by 

 the methodic examination of certain rivers. Thus, Dun- 

 bar (Z. H. xxi, 295) has published , an entire series of 

 Elbe water vibrios isolated from the water of Hamburg. 

 Abbot and Bergey have collected 110 cultures of vibrios 

 from the American Schuylkill River, on whose banks no 

 cholera has prevailed for a very long time. Part of these 



