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through the mucosa, a condition that rarely, if ever, occurs in the case
of a mucosa that is intact and healthy. It may have been that, on
account of the exceptionally hot weather at the time of the outbreak
(the 13th to the 16th May, 1925), the abnormal growth of the bacillus
Coli group in the layers of gelatine, which were placed between the
layers of beef and pork during the process of pressing (after salting and
cooking) caused such bacilli to take on virulence and to alter their
morphology), as appears to be the explanation also in the case of
summer or epidemic diarrhoea—a sort of mass infection with altered
virulence during hot weather.
In the case of the bacillus Proteus that was isolated, the matter is
different. This is a germ that has occasionally been found to be
present in cases of food poisoning, which have, consequently, been
ascribed to such cause, though, in most of the instances, there has
been a difference of opinion amongst the bacteriologists concerned.
The conclusions to be drawn from the circumstantial evidence,
and from the bacteriological and serological investgations, in connection
with the outbreak of food poisoning under investgation, are that such
outbreak was due to
(1) the bacillus Proteus : or
(2) one or other of the well-known specific food-poisoning germs
which are included in the Gaërtner or Salmonella groups—
crowded out by the bacillus Coli and the bacillus Proteus,
so as to prevent the Gaertner or Salmonella well-known
specific germs being isolated by the usual bacteriological
methods of investigation and technique; or
(3) the bacillus Coli group—mass infection and altered virulence,
due to the exceptionally hot weather and the probable action
of such hot weather on the layers of gelatine which were
used in preparing the pressed salted beef and pork (layers
of gelatine being placed between the layers of meat), and
which were inoculated with the bacillus Coli and other
germs.
The bacillus Coli and the bacillus Proteus were actually isolated
from the beef and pork, which were under suspicion, whilst serological
re-actions with some of the victims' bloods were positive macroscopically
(in dilutions of 1 in 25 and 1 in 50) to strains of the same two bacilli.
Unfortunately sufficient blood serum from the victims was not available
to allow systematic serological investigations to be conducted with
strains of the different well-known specific Gaertner or Salmonella
groups of bacilli of food poisoning.
The circumstantial evidence is complete: the bacteriological
evidence is incomplete, but suggestive.