122
Scientific Memoirs by
Hofmann's re
-
searches.
Subsoil water
pollution.
Are our efforts
well directed?
it is quite certain that certain negative views based on observations in Europe by
Hofmann* (which indeed are very noteworthy) cannot be held to apply to this
country so far as Hofmann's conclusions are concerned ; of course the physical
processes which he so carefully elucidates, are to be found in action in tropical
and sub-tropical soils, and on a scale beyond comparison more marked in propor
-
tion to the precision and dramatic force of the meteorological conditions. It may
be confidently said that nowhere to the same extent as in the Indian plains (and
the tropical monsoon area) do we obtain the "dry zone" in the soil favourable to
the detachment and aërial transport of soil bacteria on the one hand, and the
circulatory connexion between the upper and third layers of the soil (in which
latter the subsoil water lies) during monsoon conditions, on the other hand.
Hofmann's papers must be studied in order to obtain an appreciation of what
these physical processes involve, in a country where all refuse finds its way directly
to a porous alluvial soil, where the ground-water is subject to large fluctuations
and overlarge areas, and rises under the influence of the monsoon to within a foot
or two of the surface, and from which drinking-water supplies are largely obtained.
Observations on the bacterial flora of our water-supplies at different seasons, on
the lines of Dr. Houston's experiments set forth in the Reports of the Medical Officer
to the Local Government Board (for 1897-98 and 1898-99) are much to be desired
on the part of medical officers of jails and regiments. Médécin- Major Vincent, Pro
-fessor attached to the Val-de-Grace Army Medical School, in a paper read before
the Paris International Congress (1900), gives the results of the bacteriological
observations he made on the subsoil water of a military camp in Algiers both
before the arrival, and again at intervals during the sojourn, of the troops. The
result of his work was to show that the number of microbes in the subsoil water
rose regularly and progressively in a few weeks from 200 to 14,900 per cc., and
from 37o to 38,000 per cc., on two different occasions respectively. "The
pollution of the subsoil water was therefore in proportion to the duration of the
sojourn of the troops" ; and "these researches show that infectious microbes,
deposited on the surface of a sandy soil, can penetrate to the subsoil water through
a bed of sand fifteen feet in thickness," where the level of the ground-water varies
considerably with drought or rain. "The use of this subsoil water brought about
epidemics of typhoid fever every year which have almost entirely disappeared
since the introduction of a pure Artesian supply."
All these considerations point to the necessity of reconsidering the hygienic
value of our present methods of waste removal and disposal, of water-supply
and of drainage. Is it possible to study the conditions actually obtaining in
our cantonments and their affiliated bazaar communities, as set forth year by
year in the reports of medical officers, without coming to the conclusion that a
* Archiv für Hygiene, Vols. I and II.