WATER SUPPLY AND PUBLIC HEALTH. 
39 
As the river and its tributaries receive sewage at many inter- 
mediate points, the 66 previous sewage or animal contamination ” 
at Hampton ought to be considerable ; the fact that it is not 
seems to prove that much of the sewage has been destroyed. 
The Commissioners explain this apparent anomaly by the 
subsidence of suspended animal matter in quiet parts of the 
river. Sir B. Brodie and Dr. Lyon Playfair contend that sewage 
may not be (often certainly is not) fully oxidised even after 
long carriage in river water. Professor Wanldyn states that 
although urea is rapidly transformed into ammonia and car- 
bonic acid, yet that albumenised matter is very persistent indeed. 
Mr. Simon puts the matter in the right light in his evidence 
before the Water Supply Commissioners. He said : “ Water 
into which sewage has been discharged is, in relation to the 
matter now under consideration, an experiment on the health of 
the population , and I do not think that that experiment ought 
to be tried.” 
With regard to the maximum amount of organic matters 
which may be allowed in drinking water, the following state- 
ments will be useful. The Eiver Pollution Commissioners believe 
that surface or river water should not contain more than 0*2 
part of organic carbon, or *03 part of organic nitrogen, in 
100,000 parts. Spring and deep-well water should not contain 
more than OT part of organic carbon, or *03 part of organic 
nitrogen in 100,000 parts. 
Professor Wanklyn states that efficiently filtered water may 
contain from 0*05 to nearly 0T0 parts of albuminoid ammonia 
per million ; when the amount rises to 0T0, or exceeds it, there 
is defective filtration. “ It is a matter of observation that 
diarrhoea is frequently prevalent in communities which drink 
such water.” Free ammonia exceeding 0*08 part per million 
generally denotes recent contamination with urine. Much 
albuminoid ammonia, little free ammonia and little chlorine, 
denote vegetable contamination ; such water is very injurious to 
health.* 
Dr. Frankland and Mr. Morton sum up in the following 
table their observations on the relative value of waters : f — 
Wl , f \ ®P rin ? ™ ter C 19 ®) } Very palatable 
Wholesome J 2. Deep-well water (157) j J r 
[ 3. Upland surface water (195) 1 Moderately 
~ . . J 4. Stored rain water (8 — of rain water, 73) J palatable 
uspicious ^ g Surface water from cultivated land "1 n^5) I Palat- 
Dane-erous I 6< River water to wlR ch sewage gains access J 1 f able 
1 7. Shallow-well water (420) 
* These observations are quoted from “Water Analysis,” 3rd ed., 1874, 
pp. 37, 39. 
t Pp. 129 and 425 of Sixth Report. I insert, within parentheses, the 
number of analyses on which the generalisations are based. 
