92 MICEO-ORGANISMS IN WATER 



and gravel before delivery. The following are the 

 results obtained : — 



Filtered and Unfiltered Biver BJidne Water (G. Roux, 1890) 



Number of Micro-orgauisms per c.c. 



Rhone (above Lyons) .... 75 



FUter bed 7 



Reservoir (low service) ... 18 



Reservoir (high service) .... 26 



Tap-water 60 



Rh6ne (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 laro'e number of examinations made of this 

 water. 



Biver Saone above and beloto Lyons (G. Rous, 1890) 



Niimber of IMicro-organisms per c.c. 

 Saone (above Lyons) .... 586 

 Saone (Moiiton 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 ^ in 

 1885-86, and by Frank ^ 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 flow 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 



^ Bericht der Deputation filr die Verwaltung der Canalisations- 

 werTce, Berlin, 1883. 



^ Zeitschrift fiir Hygiene, vol. ii. p. 401. 

 ^ Ibid. vol. iii. p. 355. 



