496 BACTERIOLOGY. 



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 : the 

 evacuations should be examined as soon as possible 

 after they have been passed. 



MICROSCOPIC EXAMINATION. 1. From one of the 

 small slimy particles seen in the semi-fluid evacuations 

 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 that is to say, somewhat as 

 minnows arrange themselves when swimming up stream 

 in schools. (Koch.) 



In 1886 Weisser and Frank 2 expressed their opinion 



1 Zeitschrift fur Hygiene und Itifiktionskleiten, 1893, Bd. xiv. S. 319. 



2 Ibid., 1886, Bd. i. S. 379. 



