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24
Annual Report of the London County Council, 1914.
steadily declined. Facts of this nature certainly appear wholly irreconcilable with the bacillus carrier
thesis.
But apart from all this, the practical limitation of typhoid in London, (and the same was true
of Belfast) to a particular social class, is incomprehensible on a theory which ascribes great importance
to transmission of disease by healthy persons (cooks, waiters, etc.) who handle articles of food consumed
by the comparatively well-to-do. Yet, once more, the recurring incidence of the disease
in certain special localities (see Annual Report of the Medical Officer of Health, County of London,
1903) with intervals of comparative freedom from the disease; its simultaneous involvement in many
instances of two or three members of a family, and its failure then to spread further in that family;
its tendency to manifest a special age incidence (loc. cit.) at the times of special prevalence—all these
are features a healthy carrier hypothesis is powerless to explain.
These considerations with regard to explosive outbreaks illustrate the failure of Koch's theory
and the applicability of a food hypothesis to instances of simultaneous occurrence of large numbers
of cases. Before passing to the sporadic cases a word may be added with regard to the intermediate
instance, that of the more or less sustained prevalence of typhoid in a particular area. Striking examples
of this have been observed in London. Several of these are given in the report of 1903 already referred
to, but a particularly remarkable one occurred in Shoreditch in 1908. There, in an area including 6 streets
with a population of between two and three thousand persons, after the occurrence of certain earlier
and smaller prevalences, some 50 to 60 cases were notified in 1908; a large amount of labour was expended
in investigating the personal and food histories of the persons attacked; they all belonged to one social
class comprising very poor people, and their inter-communications and common use of places of food
supply were closely analysed. Given a short incubation period, say, one week to a fortnight, interrelationship
between the large majority of those attacked could be demonstrated, and an hypothesis of direct
infection from person to person was carefully examined; on the other hand there was common to most
of the cases the history of purchasing fish from a coster living in the middle of the area; this man bought
the cheapest fish obtainable at Billingsgate and hawked it in the neighbourhood, and his customers and he
himself and his family one after another suffered from typhoid. The man died and his family left
the neighbourhood, and the special incidence of typhoid thereupon ceased. If allowance be made of
an interval of from a few days to three or four weeks for incubation, all the cases admit of explanation
as the result of the introduction on a few distinct occasions of infected fish into the area, during the
period of some 12 months covered by the exceptional prevalence. It will be seen, therefore, that either on
the theory of Koch or on the rival theory, explanation of the special incidence of typhoid fever could be
given; but the difficulty presents itself in the case of the former theory, that just when some hundred
or more infected persons had been newly introduced into the area the outbreak came to an end, and did
not recur; while, on the other hand, these are facts which, if the latter theory be accepted, the
disappearance of the coster who hawked the fish would sufficiently account for.
Turning now to the sporadic cases, these in quite a large percentage of the total number occur
in groups of two, three of more, and two or more members of one family may be simultaneously or
almost simultaneously attacked ; the salient feature, however, is involvement of a particular social class,
the people who occupy the light blue and purple streets of Sir Charles Booth's classification (see Annual
Report Medical Officer of Health, 1911). This behaviour of the disease accords well enough with
the food hypothesis, but is very difficult to reconcile with the carrier hypothesis of Koch. In London
sporadic cases not affecting the special class referred to are usually imported cases, and they often give a
history of eating shell fish, usually oysters; the vast bulk of the cases on the other hand affect fried
fish eaters who obtain their fish already cooked at the cheap shops in certain poor neighbourhoods.
It is important to note that a considerable amount of painstaking work has been undertaken in
London in connection with search for healthy carriers. In comparsion with effort made in Germany,
however, comparatively little has been attempted in this direction; and it is interesting, therefore,
to find that despite this fact the incidence of the disease has been steadily falling, particularly during
the period when bacteriological methods have been extensively employed elsewhere. In the
very limited number of cases dealt with in London on bacteriological lines some hostility to the carrying
out of these methods has been manifested by sufferers affected; and it is clear that it would not be
practicable to put into actual practice the restrictions which some bacteriologists consider should be
imposed ; indeed, this would be even more difficult than in the case of cerebro-spinal meningitis, in which
disease, in the light of recent experience, a general attempt to isolate healthy carriers cannot be advocated
by anyone with experience of the complications which its rigorous employment would
introduce.
It will be seen then that the available evidence points to infection being brought into London in
the large majority of cases by fish and shell fish coming generally speaking from a considerable distance.
The great improvements as regards sanitation effected in the last 50 years and particularly in the last 30
years have made London itself an eminently unfavourable field for growth and cultivation of the typhoid
poison ; the areas from which infection is derived are no longer near at hand, but are to be found on
distant polluted foreshores and in remote estuarial waters. Question was raised on the outbreak of hostilities
as to the likelihood of importation of infection into London by soldiers and refugees coming from
the seat of war, and during the later months of 1914 there were some alarmist rumours as to spread of the
disease by persons who had recently arrived from the continent. The experience acquired subsequent
to the South African war and the knowledge gained of the common method of spread of typhoid in
London made it clear that these fears were groundless. At the same time disturbance of the operations
of the fishing fleet in the North Sea and possible interference with the shell fish industry, brought about