490 BA CTERIOLOG Y. 



times resulted in demonstrating the multiplication of 

 the organisms introduced into it, while in other cases 

 they died very quickly. 



On February 8, 1884, microspira were found in a tank at 

 Saheb-Began, in Calcutta, and it was possible to demon- 

 strate 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 fsecal matters, the organisms retained their 

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

 luted contents of cesspools it was impossible to demon- 

 strate them after twelve hours. In the experiments of 

 Isicati 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 test with the water-supply of Berlin the 

 organism retained its vitality for 267 days, and in 

 another for 382 days, notwithstanding the fact that 

 many other organisms were present at the same time. 

 There is no ready explanation for these variations, 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 are present, up to 20 C., the 



