THE DIAGNOSIS OF ASIATIC CHOLERA. 477 



appear most quickly under artificial methods of cul- 

 tivation, and which, at the same time, may be consid- 

 ered as characteristic of it, viz., its peculiar morpho- 

 logy and grouping; the much greater rapidity of its 

 growth over that of other bacteria with which it may 

 be associated ; the characteristic appearance of its col- 

 onies on gelatin plates and of its growth in stab-cultures 

 in gelatin ; its property of producing indol and coinci- 

 dently nitrites in from six to eight hours in peptone 

 solution at 37 to 38 C. ; and its power of causing the 

 death of guinea-pigs in from sixteen to twenty-four 

 hours when introduced into the peritoneal cavity, death 

 being preceded by symptoms of extreme toxaemia, char- 

 acterized by prostration and gradual and continuous 

 fall in the temperature of the animal's body. 



In 1893 Koch 1 called attention to a plan of pro- 

 cedure that comprehends the points just enumerated. 

 By its employment the diagnosis can be established in 

 the majority of cases of Asiatic cholera in from eighteen 

 to twenty-two hours. In general, the steps to be taken 

 and points to be borne in mind are as follows : 



MICROSCOPIC EXAMINATION. 1. From one of the 

 small slimy particles seen in the semi-fluid evacuations, 

 obtained as soon as possible after their passage, prepare 

 a cover-slip preparation in the ordinary way and stain 

 it. If, upon microscopic examination, only curved rods, 

 or curved rods greatly in excess of all other forms, are 

 present, the diagnosis of Asiatic cholera is more than 

 likely correct; and particularly is this true if these 

 organisms are arranged in irregular linear groups with 

 the long axes of all the rods pointing in nearly the same 

 direction. 



i Zeitschrift fur Hygiene und Infiktionskleiten, 1893, Bd. xiv. S. 319. 



