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Two other observers in 1911, Zwick and Weichel,* found Gaertner group bacilli
present in 28 out of 177 mice examined. Other observers have failed.
Savage and Reid* in 1913 failed to isolate Gaertner group bacilli from the intestinal
contents of 41 rats, but isolated five strains of B. Enteritidis from the spleens (in two
cases also from the liver) of different rats.
Commenting on these observations, Savage writes :—
"In two instances Danysz's virus (B. Enteritidis) had been distributed quite recently,
"while two and a half years' previously the refuse tips and slaughter-houses from which
"these rats were obtained had been extensively dosed with this virus. It is highly probable
"that the bacilli isolated were derived (except in the two cases of recent infection) from an
"old infection with this virus, a conclusion supported by the failure to find this organism in
''the intestinal contents, and by the fact that the serum from a number of these rats
"agglutinated B. Enteritidis in high dilution."
A later investigation by Savage (1918) confirms this hypothesis, since 48 rats
obtained from a different source showed no Gaertner group bacilli or Gaertner group
agglutinins.
As regards domestic animals, the present view appears to be held that Gaertner
bacilli are not normal inhabitants of the intestines of domestic animals, though the
relation of animals already infected with types of B. Enteritidis to food poisoning is one
of importance. Bainbridge, in 1912, suggested the possibility of infection of the
alimentary canal of cattle and other domestic animals through contamination of their
food or bedding by rats.
Two German observers, Langer and Thomann, in 1914, attributed an outbreak of
food poisoning, in which there were 11 cases with two deaths, to the consumption
of a meat pasty, from the flour of which it was prepared they isolated the organism
which they considered as responsible for the outbreak. Investigation seemed to
indicate that infection of the flour had resulted from contamination with one of these
bacterial preparations.
These various observations are of considerable importance, since they tend to show
that Gaertner bacilli are not natural inhabitants of intestines of either rats or mice, but
that both these animals may be infected by these organisms, and the result may be
death or recovery or the animals may survive as carriers. The possibility, therefore, of
chronic carriers resulting as a consequence of animals partaking of baits containing
these viruses is one of importance, and additional investigation work ought to be
undertaken with a view to ascertaining whether the risks thus resulting are real, and,
if so, whether in towns where there is a possibility of carrier animals gaining access to
food and thus contaminating it, the use of viruses should not be prohibited.
(21) VARNISH.—In the course of enquiries Mr. Mayne discovered in certain
premises in the Aldgate end of the City that a rat-infested premises was periodically
dealt with by setting down pieces of cardboard covered with varnish. The circumstances
seemed to justify further investigation, and subsequent work with varnish definitely
proved that for certain purposes no better trap exists. It has been found to be
exceedingly fatal when used in premises where only a few rats have gained access.
In two or three nights such places have practically invariably been cleared. In
heavily infested places such as occur near the river, six or eight cards laid down night
after night for a continuous period result in a considerable number of rats being
caught. Typical examples of results obtained are set out in the following table.
* Quoted by Savage.