BACTERIA IN WATER. 561 



Hydrant water, as supplied to cities, has received the attention 

 of numerous investigators. The water supply of Berlin was ex- 

 amined by Plagge and Proskauer at intervals of a week from June, 

 1885, to April, 1886. Their tabulated results show considerable 

 variations. We give the figures for a single day, June 30th, 1885 : 

 Stralauer works, water of the Spree, unfiltered 4,400, filtered 53 ; 

 Tegeler works, water of the lake, unfiltered 880, filtered 44 ; high re- 

 servoir at Charlottenberg, 71 ; 75 W. Wilhelmstrasse, 121 ; Fried- 

 richstrasse, 41-42 S. W., 160 ; Schmidstrasse, 165 E., 51 ; Friedrich- 

 strasse, 126 N., 151 ; Weinmeisterstrasse, 15 C., 63. 



Wells which are supplied by water from deep strata contain few 

 bacteria, unless contaminated by surface water in which they are 

 usually very abundant. Roth examined the water of sixteen surface 

 wells in Belgard, which has a very porous subsoil, and found from 

 4,500 to 5,000 bacteria in three, from 7,800 to 15,000 in six, from 

 18,000 to 35,000 in six, and 130,000 per cubic centimetre in one. 



Forty-seven wells in Stettin, the water of which was examined by 

 Link, gave the following results : Less than 100 in six, 100 to 500 in 

 twenty-one, and in the remainder (sixteen) from 1,000 to 18,000. 



Sixty-four wells in Mainz examined by Egger, and 53 in Gotha 

 by Becker, gave more favorable results ; the number of wells in the 

 former city, in which less than 100 colonies developed from 1 cubic 

 centimetre, was 34, and in the latter the same (34). Bolton examined 

 the water of 13 wells in Gottingen, and found but 1 in which the 

 number of colonies from 1 cubic centimetre was less than 100 ; in 12 

 the number varied from 180 to 4,940. 



The water of deep wells and springs may be entirely free from 

 bacteria, or nearly so. Egger found in the water of an artesian well 

 at Mainz 4 bacteria per cubic centimetre, and the same number was 

 found by Hueppe in the deep well at the Wiesbaden slaughter-house. 

 The artesian well at the gasworks of Kiel was found by Brennig to 

 contain from 6 to 30 bacteria per cubic centimetre. In a spring at 

 Batiolettes, Fol and Dunant found 57 bacteria per cubic centimetre. 

 Furbringer obtained from springs at Jena 156 from one, 51 from 

 another, 32 from another, and 109 from another. The water supplied 

 to Danzig from the Prangenaur Spring was found in several experi- 

 ments to be free from bacteria (Freimuth). 



In a summary of results obtained in various German cities Tie 

 mann and Gartner find that sixty-nine per cent of the wells from 

 which samples of water were examined contained less than 500 bac- 

 teria per cubic centimetre. 



The water of sewers is naturally rich in bacteria. Miquel found 

 that at Clichy the sewer water contained 6,000,000 bacteria per cubic 

 centimetre. Bischoff found in water from London sewers 7,500.000, 



