SPIRILLUM OF ASIATIC CHOLERA. 385 



creased in number. Relatively the same process occurs 

 at a lower temperature, from 22 to 25 C., but the 

 process is slower, the maximum development of the 

 cholera organisms being reached at about the fifteenth 

 hour, after which time they were overgrown by the 

 ordinary saprophytes present. 



From this it would seem that the vitality of the 

 cholera spirillum in milk depends largely upon the re- 

 action: the more quickly the milk becomes sour the 

 more quickly does the organism become inert, while the 

 longer the milk retains its neutral, or only very slightly 

 acid reaction, the longer do the cholera organisms that 

 may be present in it retain their power of multiplica- 

 tion. 



According to Laser, 1 the cholera organism retains its 

 vitality in butter for about seven days; it is therefore 

 possible for the disease to be contracted by the use of 

 butter that has in any way been in contact with cholera 

 material. 



In regard to the antagonism between the cholera 

 spirillum and other organisms with which it may come 

 in contact, the experiments of Kitasato 2 led him to 

 conclude that no organism has been found which, 

 when growing in the same culture medium with it, pos- 

 sessed the power of depriving it of its vitality within 

 a short time. On the other hand, the experiments showed 

 that there were quite a number of other organisms the 

 development of which was checked, and in some cases 

 their vitality was completely destroyed, when growing 

 in the same medium with the cholera spirillum. 



From this it would appear that the disappearance of 



i Zeitschrift fur Hygiene, Bd. x. p. 513. 2 Ibid., Bd. vi. p. 1. 



