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The explanation of this extraordinary prevalence in the water of these rare orga-
nisms during October is probably as follows: that the monsoon condition washed a large.
quantity of fresh fœces into the water and that the fœces at this time of year contained
these rare bacilli in large numbers. We have however still got to explain the extra-
ordinary increase in the number of these organisms in the fœces of man and animals,
that occurred in this month.
From what we know of the flora of human and animal fœces, it seems most un-
likely that a bursting of the monsoon, or any sudden change in meteorological conditions
would cause a change in them. A week's wet and cloudy weather has occurred both
before and since October without producing a like result. The results of our researches
on fœces show clearly that these rare organisms were not present in large numbers
before October, nor have they been found since.
Consequently we have to admit that we have no satisfactory explanation to offer
for this condition of affairs. More work on this problem is necessary.
Still another extraordinary point about these organisms is their equally rapid
disappearance. From one sample only, viz., the Red Hills lake, were we able to isolate
these organisms in two consecutive weeks. In the first of these samples analysed a few
days after the rain these organisms appeared in large number; a week later only one
was obtained, that from a sample taken from the bottom of the lake, though rain had
been very persistent; in the King Institute well the organism had disappeared
entirely in a week. These facts give colour to the suggestion that these bacilli. are
very susceptible to natural influences.
It is very much to be regretted that more work was not done on this very
interesting problem when material for study was available, and that more samples of
water, from a wider. area, were not taken. More work on cow-dung and human fœces
would also have been valuable. The reason for this apparent neglect, is, that the
presence of these bacilli. was not fully recognized until long after they had disappeared
from the water, and the flood conditions had passed away. The fact also that these
organisms were present in fœces at this time was only discovered by an accident, as
the work done on human, cow and goat fœces was carried out with an entirely different
object. We consider, however, that in spite of the somewhat small. number of samples
taken the following conclusions are justified
: —
(i) That the conditions obtaining during a time of heavy monsoon weather
when fresh fœces may find their way easily into water, the whole country being
submerged, is in some way connected with the appearance of a set of rare micro-
organisms in all the water-supplies over a wide area. This fact has not been noticed
with previous and subsequent heavy rain.
(ii) That these and allied bacteria may suddenly become extremely common
in the fœces of man and animals. The cause of this increased prevalence is unknown.
(iii) That flood conditions having passed away the bacilli very rapidly
disappears from all waters. Consequently this supports the suggestion, that these
organisms are especially susceptible to natural fœces inimical to bacteria.