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could be definitely traced to infected milk from farm G
through the dairy X, in any of the districts previously
affected, though a few cases were notified during the
last two weeks in December (vide pages 50-53 and Table
III.).
Between the last week of November and the end
of December, diphtheria-infected milk from farm
G was being distributed in Lambeth Borough and in the
surrounding districts—the infection being added, in
greater or lesser quantity, daily or even twice daily, i.e.,
at 'each milking, by the infected cowman. There was a
systematic poisoning of the milk day by day for about
5 weeks. It is difficult to understand why more cases
of diphtheria were not notified, why the outbreak was
not wider spread, more especially having regard to the
fact that raw milk, at ordinary temperatures, is a suitable
nidus for the multiplication of diphtheria bacilli, and
that such germs grow and thrive more at comparatively
low temperatures than at 37 degrees C. (98.6 degrees F.).
i.e., at such low atmosnherig temperatures as obtained
during November and December. Further, the milk
population supplied daily from the suspected dairy X
numbered not less than 10,000 persons.
This limitation of the outbreak is still more difficult
to understand in view of the fact that more or less mixing
of the milks from all the farms and other wholesale
sources took place at dairy X prior to distribution, so
that the infected milk from farm G would get mixed with
the non-infected milks from elsewhere before distribution.
The infected milk from farm G was certainly not sent to
one or two particular districts only. It is probable that
only few (comparatively) of the diphtheria bacilli, or a
small amount of toxin, gained access to the milk during
the milking process, owing to the ulcer being bound up
with rag or bandage, which kept back or filtered the
bacilli or toxin, and. in addition, being situated on the
back of the finger. Probablv on this account, and owing
to the vehicle being milk, and the fact that other commoner
germs, such as staphylococci and streptococci,
crowded out or tended to crowd out the diphtheria germs,
the latter bacillus or the toxin was attenuated and of such
a mild type of virulence when distributed in the milk
to customers as to cause corresponding mild attacks of
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