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5
roughly speaking in time with the Holborn outbreak, but as this latter outbreak was only a small
one it could in no case explain the increase in the figures for London as a whole in those weeks.
In view of the possibility entertained in the first instance that Southwark and Vauxhall
water had been at fault, it was deemed desirable to study the distribution of enteric fever throughout
London during the closing weeks of the year in relation to water supply. The results obtained
may be quoted, as they give a general idea of the topographical distribution of the disease. Each,
case, it should be stated, is referred to the week in which the day on which it was notified falls.
It was found that north of the Thames some small but noteworthy irregularities had presented
themselves. The extent of these variations will be seen on reference to the diagram facing
this page, which shows that—
(i.) In those parts of North-West London supplied by the Grand Junction, West
Middlesex and Chelsea Companies, following the fall after the attainment of maximum
prevalence in the 38th-40th weeks, there was a slight rise, culminating in the 44th
week, and another slight rise in the 50th week.
(ii.) In those parts of North and Central London supplied by the New River
Company, following upon a maximum prevalence attained in the 39th and 40th weeks,
there was a rise in the 42nd-44th weeks, and further a short sharp rise in the 48th and
49th weeks. This last-mentioned rise was due to the Holborn outbreak already
referred to.
(iii.) In East London there were some marked irregularities, particularly there may
be noted the rise in the 43rd week, partially accounted for by a group of cases in NorthEast
London, and the rise culminating in the 46th week, due in the main to three groups
of cases, one in Poplar and two in Stepney. A further rise in the closing weeks of the
year will also be observed.
Turning now to the south side of the river it transpires that—
(i.) In those parts of South-East London supplied by the Kent Company there was
no specially noteworthy irregularity of incidence of enteric fever ; the maximum was
attained in the 40th week and this corresponds fairly well with the time of occurrence of
the ordinary seasonal maximum of the disease.
(ii.) In those parts of South and South-West London supplied by the Lambeth Company
a maximum was attained in the 40th week, and there was then a slight rise of
prevalence in the 42nd and 43rd and again in the 47th and 48th weeks of the year.
(iii.) In those parts of South-West London supplied by the Southwark and Vauxhall
Company a remarkable increase in prevalence was manifested between the 43rd and the
49th weeks.
On comparing the curves for the areas supplied by the several water companies it will be
seen that three periods of exceptional prevalence may be roughly marked out in the closing weeks
of the year. One toward the end of October is marked in East London, but is also traceable
in the charts of the New River and Lambeth areas. Another occurring in the 51st and
52nd weeks is marked in the New River and East London areas. A third (intermediate) prevalence
was that developed during the 43rd-49th weeks of the year, when the Southwark and Holborn
outbreaks occurred which have already been discussed. It is this intermediate prevalence to
which attention will now be more particularly directed and interest specially centres upon the
areas supplied by the Southwark and Vauxhall and East London Companies, the rise in the New
River Company's area being already sufficiently accounted for by the Holborn outbreak.
Taking first the East London area, there were in Stepney two definitely localised prevalences,
the one comprising four cases in Whitechapel, the other a group of seven cases in the east
of Stepney, confined to a circumscribed area surrounding the point where the Regent's Canal passes
from Mile End Old Town into Limehouse. To these cases, and to a group of four cases in one
house in Poplar, further reference will be made later (See area xvii. referred to on pages 7 and 8).
On examination of the area supplied by the Southwark and Vauxhall Company (which
includes an area in part supplied by the Lambeth Company) the cases well be found to have a
much more generalised distribution. The accompanying map shows the cases notified during a
portion of the period included in the 46th-48th weeks when the prevalence was at its height.
Between 21st November and 5th December inclusive 74 cases were notified from houses within
the area bounded by a red line. One of these cases was returned from hospital owing to error
in diagnosis, and three more occurred in a block of dwellings from which a number of cases
of enteric fever had already been notified during preceding weeks. Omitting these four cases
there remain 70 cases, 62, indicated by red dots, removed from houses supplied with Southwark
and Vauxhall water, 8, indicated by red crosses, from houses supplied with Lambeth water.
Having in view the ordinary behaviour of enteric fever in London at this time of year, it may
be assumed that rather more than half these cases must be looked upon as due to some superadded
cause over and above the causes normally operative. But if some 25 or 30 cases, due
to such ordinary causes, be more or less uniformly distributed over the area, and then, in
addition, 40 or 45 further cases due to special causes be distributed, the question as to whether
or no the total cases will show evidence of a tendency to grouping will be necessarily complicated
by the 25 or 30 cases scattered more or less uniformly over the area. Having this consideration
in view it is necessary to examine the distribution of the cases shown on the map somewhat more
closely.
It will be noted, then, that Bermondsev and portions of Southwark, Lambeth, Battersea and
Wandsworth near the river, all thickly populated areas, are almost free from cases; on the other
hand, there is suggestion of grouping of cases—
(i.) In North Camberwell, in the neighbourhood of the Grand Surrey Canal, and
more particularly of its southern extension into Peckham (8 cases).