THE DIAGNOSIS OF ASIATIC CHOLERA. 495 



In an atmosphere of carbon monoxide its vitality is lost 

 in nine days, and in general the same may be said for it 

 when exposed to an atmosphere of nitrous oxide gas. 



From what has been said, we see that the spirillum 

 of Asiatic cholera, while possessing the power of pro- 

 ducing in human beings one of the most rapidly fatal 

 diseases with which we are acquainted, is still one of the 

 least resistant of the pathogenic organisms known to us. 

 Under conditions most favorable to its growth its de- 

 velopment is self-limited ; it is markedly susceptible to 

 acids, alkalies, other chemical disinfectants, and heat ; 

 but when partly dried upon clothing, food, or other 

 objects, it may retain its vitality for a relatively long 

 period of time, and it is more than probable that in this 

 way the disease is often disseminated from points in 

 which it is epidemic or endemic into localities that are 

 free from it. 



THE DIAGNOSIS OF ASIATIC CHOLERA BY BACTERIO- 

 LOGICAL HfiETHODS. 



Because of the manifold channels that are open for 

 the dissemination of this disease it is of the utmost 

 importance that it should be recognized as quickly 

 as possible, for with every moment of delay in its 

 recognition opportunities for its spread multiply. It 

 is essential, therefore, when employing bacteriological 

 means for 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 con- 

 sidered as characteristic of it, viz., its peculiar mor- 

 phology and grouping; the much greater rapidity of its 

 growth over that of other bacteria with which it may 



