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Bulstrode's two comprehensive reports, that on oysters in 1896, and that on other shellfish in 1911,
especially focused attention on the subject. There can be no doubt that considerable improvement
resulted, though even during the years of war clear evidence of spread of typhoid by shellfish was still
forthcoming.
The original oyster scare of the nineties caused diminished consumption of oysters and led to
improvements in cultivation and storage. For many years after this, however, cockles and mussels
derived from grossly polluted sources continued to be supplied to the poorer population of the large towns
and to be consumed locally at seaside resorts. The Report on "Fisheries in the Great War" (1920)
described some of the changes which have recently occurred. Thus the practical disappearance of the
Tees oyster and mussel fishery, under the Tees Fishery Order (1909), has been accompanied by a remarkable
fall in the greatly excessive amount of typhoid fever in Durham. An account is given, too, in the
Reportjof Professor Stanley Gardiner's investigations in the Fal estuary. The steps taken to improve
the conditions in the oyster beds in the main estuary are described, as also are the experiments made
with regard to the keeping and despatch of oysters. Professor Gardiner says: "So long as the shells
remain closed and do not lose their shell water, the oysters remain good for human consumption, and
cannot be infected on their journey to the consumer."The process of" teaching the oyster to keep its
mouth shut "(as it has been colloquially termed) is described, and the optimistic view is expressed that
"cases of typhoid infection from oyster beds are now almost non-existent"; Professor Gardiner attaches
considerable importance, however, to the subsequent risk of infection at retail shops, for, he says, "the
danger from the handling of oysters by typhoid carriers is well known." This last-named danger is,
of course, purely hypothetical, as no actual proof of such transmission has ever been given. The
Report also refers to investigations at Conway, where " a practical method of cleansing polluted
mussels " has, it is claimed, been devised. Apart from concrete biological and physiological observations,
it was necessary, in order to attain the end in view, "to get to know the mussels ' as a shepherd
knows his sheep,' that is to say it was necessary to be able to interpret at a glance what is going on,
whether the mussel is normal or not; what it is doing, and why; and what it has been doing during the
preceding 12 hours or so."
Further evidence as to improvements carried out will be referred to later. On the whole it
may be assumed that many of the worst conditions referred to by Dr. Bulstrode have been either done
away with altogether, or the risk has been lessened, and a considerable share of the decline in typhoid
fever, particularly in the last 20 years, must be attributed to this.
With the outbreak of war the sale of foreign shellfish in this country ceased. That of native shellfish
did not undergo much diminution, the sale of oysters actually increased.
The figures for mussels and cockles, 1910-19, are as follows :—
1910 295,382 cwte. 1914 456,399 cwte. 1918 374,209 cwts.
1911 309,702 „ 1915 395,617 „ 1919 423,099 „
1912 379,090 „ 1916 309,973 „
1913 428,232 „ 1917 349,240 „
Thus while the gathering of cockles and mussels was at first checked, at a later date food scarcity
undoubtedly stimulated the industry, and the actual reduction in typhoid fever, which can legitimately
be ascribed to falling off in the use of polluted shellfish in the last six years, is probably not so great
as might at first sight have been anticipated.
Causation of typhoid fever by sewage-polluted fish.
As regards fish, the facts are less well-known, and must be set out at greater length. The prevalences
first attributed to eating fish were three outbreaks, occurring in widely separated parts of
London (Southwark, Lambeth and Kensal Town) in September, 1900. In the first of these some 120
cases occurred, in the second and third some 50 and some 30 respectively. (Ann. Rep., 1900, Appendix I.)
Later enquiry aroused suspicion that many other prevalences of typhoid, occurring outside London at
about this time, may have had a like origin. Moreover, in these the first recorded fish outbreaks, suspicion
especially attached to small flat fish, which there was reason for thinking had been consumed ungutted,
i.e., the fish was eaten entire, gut and all. In 1903 (Ann. Rep., 1903, Appendix I.) two further fish
prevalences in Holborn and Southwark were reported upon. By that time the danger of consuming
ungutted flat fish was clearly recognised, as will be seen from the following extract from the 1903 report:
"Experience in Southwark in 1900 indicated that it was the 'halfpenny bit' which was
especially mischievous, and it was found that this consisted in some instances, at any rate, of an
entire fish, and, therefore, of a very small one. 'Dabs' and 'small plaice 'are sometimes
bought in quantity at Billingsgate, more particularly in the summer, at times when large fish are
scarce. In July, 1901, 'dabs' were being sold at that market at 3s. to 2s. 6d. per trunk of about
84 lbs.—i.e., at approximately ½d. per lb. As it takes one man about 1½ hours to clean a trunk of
small fish, the temptation during busy times to remove the heads only, the fish being fried with
the gut in them, must be great; in the case of small fish there is, moreover, special difficulty in
removing the gut. It is noteworthy in this connection that sufferers from enteric fever have in
several instances complained that the fish eaten by them had a disagreeable flavour, and even
that it made them sick, while insufficiently cleansed fish is, it appears, well known to have a
characteristic bitter taste. Imperfect gutting is apparently far from uncommon, at any rate
at busy seasons. I have seen small fish from which the heads and portions of the intestinal
contents had been cut away by one stroke of a knife but from which the gut had not been completely
removed, displayed for sale in a fried fish shop, and among some 30 or 40 penny and
halfpenny pieces of fried fish purchased two samples were obtained—one from North London
and one from South London—in which the intestines were in the fish. It may be surmised
that frying under these conditions,.'having regard to the short time of exposure in the dripping
or oil to a high temperature, would be unlikely to result in sterilisation of the intestinal contents.'