A STUDY OF THE BACTERIOLOGY OF DRINKING WATER-SUPPLIES
IN TROPICAL CLIMATES.
•
CHAPTER I.
INTRODUCTORY.
ALL who have had anything to do with the bacteriology of water in India must
entertain considerable doubt as to whether the standards of purity in common use
amongst sanitarians in England are suited to this country. One is struck with many
serious and radical differences between the waters, that are used for human consump-
tion in the two parts of the world, as a reference to what follows in this report will
demonstrate beyond all shadow of doubt. The simpler tests, that give a rough estimate
of the total fœcal contamination of any sample, show that most of the waters, which
have to be used. in this country, are simply loaded with fœcal contamination, so much
so that no analyst in England would ever dream of passing them as fit for human
consumption. It may be stated that such drinking water is the rule in India and not
the exception.
The ordinary rural population possess absolutely no idea whatever of what
constitutes either an undesirable or dangerous contamination, and it is within the
experience of all officers in this country, that a village water-supply may serve the
purpose of a drinking supply for the inhabitants, a place where clothes and cattle
are washed, and in not a few cases, the immediate neighbourhood is used by the
villagers as a latrine in the early morning. It is hardly credible that people are
so backward as to raise no serious objection to throwing cholera corpses into the
only available water-supply for a large village, and yet such occurrences are
common in some parts of this country. The extraordinary part of this state of
affairs is, that the results of using sewage as a drinking water are not always apparent,
even on enquiry. True we have frightful epidemics of cholera, that dysentery is
nearly always present to some extent, and bursts out at certain periods of the year ;
true also that the infant mortality is 178 per thousand children born ; but when one
considers that most of the water used by the people is utterly unsuitable, according to
our ideas, one cannot but be struck with the fact that the results do not appear to be
in proportion to the cause at all times. This contention is better exemplified by a
study of the analyses in the following report ; of the 18 towns that are all provided
with a protected supply, the water supplied in a large percentage of the samples, is so
bad that no Sanitary Officer in Europe would pass it as fit for human consumption,
and yet a reference to the health statistics of these towns show that the people are
distinctly favoured as compared with their brethren in rural areas, and that their
health is broadly speaking satisfactory. Cholera is rare on the whole ; dysentery
and diarrhoea are moderately prevalent, and the death rate is fairly low. This
being so, it would be an entirely mistaken policy on the part of sanitary advisers
in India to condemn these supplies, or to insist that all water must fulfil the require-
ments, that are usually accepted as necessary in England, before it is distributed to
the inhabitants of a town. Were this to be insisted on, out of the 18 protected
supplies that we possess in the Madras Presidency, not one would pass muster at
all times of the year.
Another important point of difference in the East is, that on inspection, we are sure
that a great deal of the pollution of surface waters is caused by excrement of animals,
mostly cattle and goats, whereas in England the pollution that is most common in
rivers, has its origin in sewage from large towns, which we know to be derived from
man. It is by a careful study of this latter kind of contamination that the working
standards have been arrived at in England, consequently, we have here another reason
for doubting if the application of such standards to Indian conditions is likely to be
satisfactory.