Medical Officers of the Army of India.
The results of other observers as to the viability of B. typhi in sterilized and
unsterilized sewage, respectively, bear out this opinion.
Professor Boyce, in a preliminary report to the Royal Commission, remarks that "filtra
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tion" has a marked effect on keeping back the B. enteriditis sporogenes (which is
responsible, in Klein's opinion, for acute summer diarrhœa), especially when combined
with precipitation. It was not found in the effluent from the septic tank at Manchester,
nor in the filter effluent at Chorley or Oldham, though it was obtained from the latter by
passing the effluent through a porcelain filter; but here, it is to be noted that downward
filtration after precipitation is the system used.
The ubiquity in our surroundings of both B. coli and the enteriditis sporo
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genes and the fact that they are normal inhabitants of the intestinal tract render
their presence in an effluent at most suggestive, rather than positively indicative
of the survival of true pathogenic organisms. When, as we shall propose, they
are carried away a considerable distance to light porou arable soil, which should,
and can be, consistently cultivated, it will, I think, be allowed that the possible
danger bears an altogether insignificant proportion to that incurred in the
methods at present in use.
If these considerations fail to convey conviction to the "practical man,"
then at least it must be admitted that the case for taking our share in the ex
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periments, which can alone settle this important point, is rendered all the strong
-
er, and it must be added that, with all respect to the splendid army of Engineers
which India has at its service, this question of the institution of biological me
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thods is one in which the sanitary expert, the bacteriologist and chemist, must
have the first and last word, though we should be the last to suggest that the
part of the Engineer in this work is anything but essential to success.
For, we have always to keep in view as regards disposal: (1) the perfect
mineralization of the sewage; (2) the condition of the effluent at different stages,
to ensure that, at each stage, the biological action is neither in excess nor defect
—work that can only be entrusted to a chemist, so that (3) we secure the fullest
ultimate mineralization with the highest manurial value, in the form of nitrates.
The future of the biological methods in India would appear to be excep
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tionally promising; they have already given results that have definitely settled
the main question of their practical application to Indian conditions; as a rule,
there is plenty of land to spare; the people appreciate the value of irrigation;
here, if anywhere, it is incumbent on us to replenish an exhausted soil; no
natural or artificial "dressing" has the assimilable manurial value of a biological
"effluent" if properly matured*; the methods, as employed at Simla, and generally
elsewhere, show how easily the ordinary means of collection and removal can be
utilised and adopted, though this is a counsel far short of perfection; a minimum
water-supply per head provides no difficulty; the apparently insuperable difficulty
* S e e P o o n a e x p e r i m e n t s .
MM