220 



MICRO-ORGANISMS IN WATER 



That this was the case the following experiments 

 illustrate very clearly : 



Descriptic 



River Thames at Hampton 

 River Lea at Chingford 



The organisms in the raw river- water thus under- 

 went a marked reduction after storing for two and four 

 days respectively in stoppered bottles. 1 But if these 

 waters are kept in the incubator at a high temperature 

 (35 C.), the reverse takes place in the first instance, 

 thus : 



Description 



River Thames at Hampton 



Thus a very rapid increase in the numbers present 

 took place at first, but an exposure of eight days to 



1 It should be pointed out that in these experiments with unfiltered 

 river- water the initial number of bacteria present was very large. We 

 have subsequently found that when the initial numbers are smaller and 

 the water is preserved in flasks to which there is free access of air through 

 cotton-wool stoppers, the multiplication may be very extensive. This 

 result is, moreover, in precise accordance with the experiences of Miquel 

 on the water of the Seine, in which connection he remarks : ' De 1'eau 

 de la Seine, puisee a Ivry pendant 1'ete, d'une richesse inferieure a la 

 moyenne annuelle, pent presenter des recrudescences de germes assez 

 elevees ; elle montre a cet egard une tendance manifeste a se comporter 

 comme les eaux de source ; mais que survierinent les crues, que sa teneur 

 en microbes atteigne a Tanalyse immediate 20,000 et 30,000 bacteries par 

 centimetre cube, cette faculte de s'infester spontanement disparait, et cette 

 eau impure lie pent devenir le siege de recrudescences microbiennes 

 rapides et soudaines.' 



