XXVI. J. M. SMAIL. 



MicroVifs per cc. 



(Mean of 213 samples) 17 



Ditto ditto (highest) 310 



Ditto ditto (lowest) 



River Lea imflltered ... ... ... ... 187 



River Lea from the East Loudon Water Company's 



Clear Water Wells (mean of 27 samples) ... 9 



After the 320 daily samples taken from the general filter 

 wells of the Metropolitan Water Company's, 19 samples or 

 5'9°/° were sterile, 10 samples or 3*1°/' contained more than 

 100 microbes, and of these only three samples contained 

 more than 150 microbes. Tlie ten excess samples contained 

 an average of 1 18 microbes per cc. 



Another example of the redaction of bacteria by sand 

 filtration of water drawn from rivers is at York, England. 

 The water is drawn from tlie river Ouse, the intake being 

 some distance above tlie town, but is not free from pollution 

 at this point. The examination in 1903 by Mr. Thomas 

 Fairley, Bacteriologist is viz.: — 



Unfiltered Water. Filtered Water. 



5 

 4 

 3 

 15 

 1 

 4 



It should be remarked that the water supplied by the 

 York Water Company passes first into subsiding reservoirs 

 and then through American rapid filters from which it 

 passes to the slow sand filters for final treatment. The 

 result being satisfactory, both chemically and bacterio- 

 logically. 



As a contrast to the foregoing river services, the bac- 

 teriological examination of water supplied to the City of 

 Liverpool from the different sources is quoted from the 



January ... 



... 698 



February... 



... 215 



Marea 



500 



April (heavy floods) 



... 2270 



May 



... 295 



June 



... 203 



