GENERAL REMARKS ON THE RESULTS OBTAINED IN THE
EXAMINATION OF JAIL WATER-SUPPLIES.
Bacteriological Results.—The bacteriological examination of the various drinking-waters in
the jails of this Presidency taken as a whole shows a rather serious state of affairs. In nearly
• every instance the supplies for the jails are taken from shallow wells. Consequently these
remarks must be looked upon more as a condemnation of the surface well rather than as any
direct charge of neglect on the part of the Jail Department. From a study of the analyses of
the King Institute well water * the following conclusions, which speak largely for themselves,
were arrived at:—
" (1) Just as in most other water-supplies, including rivers, tanks, springs, etc., bacillus
cloacaæ would appear to be the predominating organism in a well water after prolonged
drought.
" (2) Even a small downpour of rain, after a prolonged spell of dry weather, has a very
marked influence in increasing the number of fœcal bacilli in the water of wells situated in
porous soils.
" (3) That early showers following on a long period of dry weather have caused an
increase in the number of coli communis in the well water of the King Institute. Further
investigation is necessary before it can be stated. that this is true of all wells. It is not by any
means certain where these coli communis come from, but it is unlikely that they come from.
the surface of the ground, and probable that they remain alive in the lower layers of the soil.
" (4) That after heavy downpours of rain, in consequence of which it is certain that
surface contamination has penetrated deeply into the soil, a mixture of many varieties of fœcal
organisms is usually found in the water obtained from wells. Coli communis appears to be
present after early rains, but disappears as the rains become more plentiful.
" (5) Plentiful rains improve the quality of the subsoil water after the contaminated
surface water has run off the land.
" (6) Shallow wells are most unsatisfactory sources of water-supplies, especially if they
are situated in a highly porous soil, and unless the greatest possible care is exercised in protect-
- ing a large space of ground in their immediate vicinity from all chances of pollution."
The figures derived from the examination of jail supplies amply confirm these remarks.
The King Institute well is situated on a piece of ground that is not likely to be highly
contaminated. Consequently it is not uncommon to get a very fairly satisfactory water from
it, and it is comparatively seldom that the number of fœcal organisms in it run up to as high
as 10 to a cc. Such however is not found to be the case in jail well waters. A glance at table
No. 1 will show that 100 fœcal organisms per cc. is fairly common. Only in two instances
have samples been taken which show a reasonable degree of purity, namely, those from the tope
well in Cannanore and. the wells in the Coimbatore jail.
A study of the variety of organisms that are present shows, that in a very large number
•of instances numerous highly objectionable bacilli are to be found. Even in those wells in
which the most objectionable species are not found there is usually present a considerable
mixture of varieties. Such mixture is indicative of recent fœcal contamination as apart from
contamination due to organisms living in the ground.
Another fact that has been made out by our study of the King Institute well water is the
evil influence that rain has upon the quality of the water in wells. It must be understood that
the soil in practically the whole of this Presidency is so porous that little or no filtering action
goes on when a surface water percolates through it. It seems almost astounding that 40 or 50
feet earth should have so slight an action in purifying a water. But the fact is proved up to
the hilt by the work in. the laboratory at the King Institute. I consider that it is perfectly correct
to say that under unfavourable meteorological conditions, particularly after a sudden downpour
of rain amounting to more than an inch and a half, a very large amount of surface pollution
Vide Appendix No. 1 to the Annual Report on the King Institute of Preventive Medicine, Madras, for 1908,
Chap. 171, P1). 29 et. sea.
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