382 BACTERIOLOGY. 



the organisms introduced into it, while in other cases 

 they died very quickly. 



On February 8, 1884, comma bacilli were found in 

 the tank at Saheb-Began, in Calcutta, and it was possi- 

 ble to demonstrate them in a living condition up to 

 February 23d. 



Koch states that in ordinary spring- water or well- 

 water the organisms retained their vitality for thirty 

 days, whereas in the canal- water (sewage) of Berlin they 

 died after six or seven days; but if this latter were 

 mixed with fecal matters, the organisms retained their 

 vitality for but twenty-seven hours; and in the undi- 

 luted contents of cesspools it is impossible to demon- 

 strate them after twelve hours. In the experiments of 

 Nicati and Rietsch they retained their vitality in steril- 

 ized distilled water for twenty days; in Marseilles canal- 

 water (sewage), for thirty-eight days; in sea- water, 

 sixty-four days; in harbor-water, eighty-one days; and 

 in bilge- water, thirty-two days. 



In the experiments of Hochstetter, on the other hand, 

 they died in distilled water in less than twenty-four 

 hours in five of seven experiments; in one of the two 

 remaining experiments they were alive after a day, and 

 in the other after seven days. 



In one experiment with the domestic water-supply of 

 Berlin the organism retained its vitality for 267 days; 

 in another for 382 days, notwithstanding the fact that 

 many other organisms were present at the same time. 

 There is no single ground upon which these variations 

 can be explained, for they depend apparently upon a 

 number of factors which may act singly or together. 

 For example, in general it may be said that the higher 

 the temperature of the water in which these organisms 



