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Scientific Memoirs by
9. Cultivations fail to show any differences in the nature of the schizomycetes pre-
sent in the two areas, and show no important difference in regard to their numbers.
10. The phenomenon must, thus, apparently be explained either as due to a special
accumulation of the ferment, elaborated in connection with the growth of the schizomycete
organisms, in the upper portions of the fluid, or, more probably, as the result of special
accumulation there of those constituents in the milk which are the subjects of the fermen-
tive change which leads to the alteration in reaction and coagulation.
11. Coagulative change ultimately occurs in specimens of milk which have been de-
prived of all their living schizomycete contents but Bacillus subtilis.
12. This, however, differs in nature from the common coagulation of unboiled speci-
mens in occurring apart from the development of acidity to any considerable extent, or as
a constant event, in the fluid, and in the character of the resultant coagula, which form a
finely pulverulent deposit in place of the large dense masses occurring in the case of com-
mon coagulation.
13. The measures which suffice to secure true sterilisation in milk differ somewhat in
different instances, due to differences present in the condition of the Bacilli at the time of
their application—measures serving to secure sterilisation where no spores are present
being naturally not necessarily capable of producing the same effect where spores exist.
14. Complete sterilisation can be certainly arrived at by means of subjecting the milk
to the temperature of boiling water for some hours, and after this the fluid remains practi-
cally permanently unaltered save in undergoing a gradual evaporative diminution in bulk.
15. The milk in ordinary use in the bazaars and European houses in Calcutta is not a
favourable medium for the multiplication or even continued existence of Comma-Bacilli.
16. Their introduction does not interfere with the normal processes of excessive mul-
tiplication of the common lacteal schizomycetes and the acid fermentation accompanying
it, and, as the latter advances, the Comma-Bacilli rapidly cease to multiply and die out, so
that, under normal circumstances, the medium is free of living specimens of them within
the course of twenty-four hours.
17. Milk, however, which has been exposed to boiling for a short time becomes a
medium in which, for some time, at all events, an excessive multiplication of Comma-
Bacilli certainly follows their access.
18. The presence of the Comma-Bacilli in such cases seems to exert a temporary
repressive influence on the development of the normal content of Bacillus subtilis.
19. The repression is, however, only temporary, and Bacillus subtilis again becomes
very abundant.
20. This rejuvenescence of Bacillus subtilis is sometimes associated with marked
decrease in the activity of multiplication of the Comma-Bacilli, or even with their complete
suppression, but, in other cases the two species may persist in large numbers in associa-
tion in the same medium for a period of several weeks' duration.
21. Sterilised milk affords an even more favourable nidus for the growth and multipli-
cation of Comma-Bacilli than boiled milk does, apparently due to the protection which it
provides against a struggle for existence.
These facts, beyond their purely scientific interest, appear to have an im-
portant bearing practically. They seem to indicate that the ordinary milk
supply of the bazaars of Calcutta, and presumably of India generally, furnishes
a medium which, from the high degree to which it is normally contaminated by
schizomycetes, whose growth is associated with processes of acid fermentation