THE DIAGNOSIS OF ASIATIC CHOLERA. 387 



the cholera spirillum, and Percy Frankland^ states that 

 in an atmosphere of this gas it dies in about eight days. 

 In an atmosphere of carbon monoxide its vitality is 

 lost in nine days, and in general the same may be said 

 for it when under the influence of an atmosphere of 

 nitrous oxide gas. 



From what has been said we see that the spirillum of 

 Asiatic cholera, while possessing the power of producing 

 in human beings one of the most rapidly fatal forms of 

 the disease 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 development is self-limited; it is conspicuously sus- 

 ceptible 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 

 it is in this way that the disease is often carried from 

 points in which it is epidemic or endemic into localities 

 that are free from the disease. 



THE DIAGNOSIS OP ASIATIC CHOLERA BY BACTERIO- 

 LOGICAL METHODS. 



Because of the manifold channels that are open for 

 the dissemination of this disease it is of the utmost im- 

 portance that its true nature should be recognized as 

 quickly as possible, for with every moment of delay in 

 its recognition opportunities for its spread are multiply- 

 ing. It is essential, therefore, when employing bacteri- 

 ological means in making the diagnosis, to bear in mind 



1 Ibid., Bd. vi. p. 13. 



