92 MICRO-ORGANISMS IN WATER 



and gravel before delivery. The following are the 

 results obtained : 



Filtered and Unfiltered Ewer Rhone Water (G. Eoux, 1890) 



Number of Micro-organisms per c.c. 



Rhone (above Lyons) .... 75 



Filter bed 7 



Reservoir (low service) .... 18 



Reservoir (high service) .... 26 



Tap-water 60 



Rhone (below Lyons) .... 800 



The river Saone, on the other hand, is much richer 

 in bacterial life, as will be seen from the following 

 results, although less so than the rivers Seine, Marne, 

 and Ourcq at Paris. The figures obtained are the 

 mean of a large number of examinations made of this 

 water. 



River Saone above and below Lyons (G. Roux, 1890) 



Number of Micro-orgauisms per c.c. 



Saone (above Lyons) .... 586 



Saone (Mouton bridge) .... 1,594 



Saone (Tilsitt bridge) . . . .860 



Saone (below Lyons) .... 4,280 



The river Spree, which supplies Berlin, has been 

 bacteriologically investigated by various workers, not- 

 ably by Koch * in 1883, by Plagge and Proskauer 2 in 

 1885-86, and by Prank 3 in 1886-87. 



Frank collected a large number of samples of the 

 river in and below Berlin, to trace if possible the con- 

 tamination which the Spree undergoes in its now through 

 the city. 



The following table gives the result of these bacterio- 

 logical observations. It should be mentioned in ex- 

 planation of the places selected for the collection of the 



1 Bericht der Deputation fur die Venualtung der Canalisations- 

 werJce, Berlin, 1883. 



2 ZeitscJirift fur Hygiene, vol. ii. p. 401. 



3 Ibid. vol. iii. p. 355. 



