SPIRILLUM OF ASIATIC CHOLERA. 351 



From this it would appear that the disappearance of 

 the cholera spirillum from mixed cultures and from the 

 evacuations in so short a time as has been mentioned, is 

 due more to unfavorable nutritive condition than to the 

 direct action of the other organisms present. 



When completely dried, according to Koch's experi- 

 ments, the cholera spirillum does not retain its vitality 

 for longer than twenty-four hours, but by others its 

 vitality is said to be destroyed by an absolute drying of 

 three hours. In the moist conditions, as in artificial 

 cultures, vitality may be retained for many months, 

 though repeated observations lead us to believe that, 

 under these circumstances, the virulence is diminished. 

 According to Kitasato, 1 they retain their vitality when 

 smeared upon thin glass cover-slips and kept in the 

 moist chamber for from 85 to 100 days, and for as 

 long as 200 days when deposited upon bits of silk 

 thread. 



In the course of his studies upon the destiny of 

 pathogenic micro-organisms in the dead body, Von 

 Esmarch 2 found that, when the cadaver of a guinea- 

 pig dead from the introduction of cholera organisms 

 into the stomach, was immersed in water and decom- 

 position allowed to set in, after eleven days, when de- 

 composition was far advanced, it was impossible to find 

 any living cholera spirilla by the ordinary plate methods. 



A similar experiment resulted in their disappearance 

 after five days. In another experiment, in which de- 

 composition was allowed to go on without the animal 

 being immersed in water, none could be detected after 

 the fifth day. 



1 Zeitschrift fur Hygiene, Bd. v. p. 134; 



2 Ibid., Bd. vii. p. 1. 



