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Onsets of Attacks.
Table I. gives the dates of the onsets of the attacks
in all the cases notified, and Table III. sets out the
numbers of patients sickening daily, in the different
districts, and shews that the incidence of the
disease was greatest in the first two weeks in
December. The maximum number of patients sickening
on one day was 11, viz., on December 1st (9 patients
having sickened on the previous day, November 30th).
Arranged weekly, the growth of the outbreak is readily
seen, as follows:—
No. of cases Per cent, of
sickening. total cases.
Week ending Nov. 23rd 2 = 1.7
„Nov. 30th 27 = 23.9 29.5
„Dec 7th 41 = 35.1
„Dec. 14th 37 = 31. 6 19.2
„Dec. 21st 8 - 6.8
„ Dec. 28th 2 - 1.7
Total 147 100.0
The sudden increase of cases sickening during the
last week in November still further increased during the
first two weeks in December and then suddenly decreased
during the third and fourth weeks in December.
Channels of Infection.
The incidence of the outbreak in all the affected
districts was more or less localised, and appeared to point
to some factor, or factors, at work over a circumscribed
area or areas.
The usual common channels, by which diphtheria is
known to spread, were investigated in each notified case,
e.g., (a) contact from person to person, (b) school influence
(day, Sunday, and dancing schools), (c) insanitary house
conditions, and (d) defective drainage or sewerage areas,
but no satisfactory evidence could be obtained, pointing
to one or other, or all, of these usual common channels of
infection being the channels through which the outbreak
had spread to the various districts affected—the cases notified
being not sufficiently definitely localised for channels
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