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7
As regards the Lambeth cases under the heading (ii.), it was found that at a time
corresponding with that of infection the majority of the cases grouped on either side of South
Lambeth-road obtained wet fish from one of two shops close to one another, and most of the persons
attacked bought indifferently at one or the other shop ; no other article of food, so far as could
be ascertained, was obtained from any common source by all the sufferers. Turning now to the
remaining eight cases two sufferers proved to have been regular customers of a particular vendor of
fried fish, and one or more of the others may also have obtained fish from the same shop. It was
noted that the vendor carried on business under a name which was that of the man whose customers
were attacked in one of the fried fish outbreaks in 1900.
As regards group (iii.), one of the cases was a regular customer of a particular fried fish
vendor, and one or more of the others may have obtained fish from this man. The vendor in
question acted as manager of the shop which supplied fish to the sufferers in the fried fish outbreak
of 1900 just referred to.
Group (iv.) included three cases in one house, and these three patients, and at least one
of the two remaining sufferers, were habitual fried fish eaters, and shortly before their illness
obtained tish as a general rule from a particular shop. This shop is situated in an area to which
further attention will be directed in the sequel. (See paragraph at bottom of page 8.)
Reference has been made to the existence of localised groups of cases on the north side of
the Thames. (See page 5.) Some inquiries were made by Mr. Wood as to cases in Stoke
Newington, and here reasons for suspecting infected fish as a cause were forthcoming, particularly
in the case of a group notified in the 42nd week. Interest specially centres, however, upon
the two Stepney groups and the Poplar group previously mentioned which occurred contemporaneously
with the Holborn cases. Mr. Shapley ascertained, in the case of the group of
four cases in Stepney, that all the sufferers had shortly before attack bought wet fish from costers'
stalls in a particular street (in area xx. See page 9.), and as regards the group of seven cases in
Stepney he found that the sufferers had purchased fish from hawkers, but it was not possible to
demonstrate that all had obtained fish from one particular hawker. In neither of these groups
had there, so far as could be ascertained, been any other common source of food supply at a time
corresponding with that of infection. The group of four cases in Poplar consisted of children from
4 to 10 years of age living in a house situated in an area (area xvii.) to be referred to later.
(See page 8.)
It will be seen, therefore, that an infected fish hypothesis is consistent with all the known
facts as to the prevalences in Stepney and in South-West London in the 46th, 47th and 48th
weeks of 1903, and in view of the facts of the occurrence of the Holborn outbreak in the 48th and
49th weeks, and of that of the Southwark outbreak a few weeks previously, there is strong ground
for suspecting that infected fish was responsible for the increased prevalence of enteric fever in
London manifested at this time.
(d) The behaviour of enteric fever in certain areas in London during the years 1896-1903.—
This behaviour can "Best be understood by reference to the diagram appended in which are shown
the cases notified in each month of the period under review. Cases occurring among persons aged
3 to 25 inclusive are indicated by hatched squares, cases at other ages by black squares. In
instances in which a second or third case was notified from a house within 10 days of a first
notification, the later case is distinctively indicated by a cross. In instances in which a
second or third case was notified, after more than 10 days and generally speaking within two months
of the notification of a first case, the later case is indicated by a cross placed below the base line,
distinction always being made in respect of age by employment of different types of cross. (See
Diagram.)
Charts i. and ii. relate to areas (in Southwark and Lambeth) in which outbreaks of enteric
fever due to the consumption of fried fish occurred in September, 1900. In the area iii. (Kensal
Town) an outbreak occurred at about the same time, and this was probably caused by infected
fish purchased in an uncooked condition; iv. relates to the central portion of the area in which the
Southwark outbreak of 1903 (see Appendix II.), due to fried fish, occurred at the end of October, the
cases being notified in November, 1903 ; v. and vi. relate to areas in which outbreaks, probably due
to the same cause, occurred about three weeks later, the cases being notified in December, 1903 ; it
should be noted that in area v. (central portion of area referred to in Appendix I.) there was not,
as in i., ii., iii., and iv., a single retail shop in question, but two retail shops were implicated, and
in area vi. (Kennington) there were in December, 1903, only three cases of illness; these two outbreaks
v. and vi. stand, therefore, on a footing different from that of the other outbreaks.
Limiting consideration in the first instance to outbreaks of considerable size, examination
of charts i. and ii. shows that—
(1) The special prevalence was accompanied by notable increase in the percentage
of multiple attacks in houses. Additional eases occurring within 10 days of a first case
are indicated on the chart by a cross occupying one square. The normal percentage of
such cases may be taken, on the basis of the London notification figures, as about
5 per cent, of the total number ; in the special prevalences i. and ii. it exceeded 20 per
cent.
(2) The special prevalence was accompanied by marked increase in the percentage
of cases at the ages 3 to 25 inclusive. Cases at the ages 0 to 2 and 26 onwards are
indicated on the chart by black squares or by distinctive crosses; the percentage of such
cases to the remaining cases may be taken, on the basis of the London notification
figures, as 50 per cent.; in the special prevalences in areas i. and ii. it fell to about
8 per cent, and 22 per cent, respectively.
The special prevalence in area iii. exhibits features closely resembling those indicated as
characterising i. and ii. The preponderance of hatched squares over black squares was, however,