DIAGNOSIS OF ASIATIC CHOLERA. 353 



plying. It is essential, therefore, when employing bac- 

 teriological means in making the diagnosis, to bear in 

 mind those biological and morphological features of the 

 organism that appear most quickly under artificial 

 methods of cultivation, and which, at the same time, 

 may be considered as characteristic of it, viz., its peculiar 

 morphology 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 

 colonies on gelatin-plates and of its growth in stab 

 cultures in gelatin ; its property of producing indol and 

 coincidently nitrites in from six to eight hours in pep- 

 tone 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 a publication recently made by Koch 1 he called 

 attention to a plan of procedure that is employed in 

 this work in the Institute for Infectious Diseases at 

 Berlin. In this scheme the points that have been 

 enumerated are taken into account, and by its employ- 

 ment 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 material 

 should be examined as early as possible after it has 

 been passed. 



I. Microscopic* examination. From one of the small 

 slimy particles that will be seen in the semi-fluid evac- 



i Zeitschrift fiir Hygiene, 1893, Bd. xiv. 



