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This table shows that 0.9 per cent. of the cows examined were certified by the Council s
veterinary inspector to have clinical symptoms of tubercular disease of the udder. The supply of
milk for human consumption from the cows thus affected was immediately stopped.
Milk exami
nation :
mortality of
inoculated
guinea-pigs
Reference to the table on page 69 shows that in 269 cases the examination of samples was
not completed owing to accident and other causes. In the large majorityof these cases the inoculated
gninea-pigs died of some acute infection before there was time for tuberculosis to develop. In this
way it was found, for example, that prior to June, 1909, in some 16 per cent. of the samples taken,
the examination for tubercle could not be successfully concluded. The Council decided, therefore,
on 15th June, 1909, to have the matter investigated by the Lister Institute with a view to learning
the causes of this "non-tubercular mortality"' among guinea-pigs, and in due course Dr. Martin,
F.R.S., the Director of the Institute, submitted a report on the enquiry made by Dr. R. A. O'Brien
(see Chapter XXXII., page 115).
Dr. O'Brien found that more than one-third of the guinea-pigs inoculated (3,069 out of 9,016)
died before tuberculosis had time to develop, and he notes that the two main causes of this "nontubercular
mortality," were two diseases in which deposits were found, in the liver and spleen, from
which deposits in one disease, B. pseudo-tuberculosis rodentium, and in the other, B. aertryck, were
recoverable in pure culture.
As regards B. aertryck, Dr. O'Brien points out that this bacillus is an occasional inhabitant
of healthy guinea-pigs' intestines, and is under normal conditions not pathogenic, but that, if the
animal's resistance is lowered, as for example by injection of milk sediment, the bacillus may migrate
from the intestines into the organs and produce septicaemia. In the same way B. pseudo-tuberculosis
rodentium is commonly met with in guinea-pigs, producing normally a chronic disease, though
occasional outbreaks of a more acute form may occur. Dr. O'Brien inclines, therefore, to the view
that a large part of the mortality among guinea-pigs inoculated with the sediment of milk results
from a lowering of the general health of the guinea-pig by the inoculation, and that this permits
a disease which is latent or chronic to progress to a fatal issue or enables bacilli normally present
in the guinea-pig's intestines to escape into the circulation and cause death.
Offensive businesses.
Slaughterhouses
In the year 1909 the County Council received 257 applications for licences for slaughter-houses'
and granted 255. The following table shows the number of applications received and the number of
slaughter-houses licensed in recent years.