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are kept must certainly become infected, and this can readily obtain access to
the vessels during the' operation of milking. It thus becomes a most important
matter to determine how far the milk supply of a town is infected in order to
consider as to what means should be adopted to combat this source of danger.
At the suggestion of your Medical Officer, Professor Klein was asked to
make a preliminary examination of typical samples of milk coming from
various parts of the country into the City. These were all taken on arrival,
and before any chance of contamination within the district could occur. They
represented the milk supply from Essex, Suffolk, Cambridgeshire, Hertfordshire,
Staffordshire, Derbyshire, Buckinghamshire, Somersetshire, Cheshire
Huntingdonshire and Middlesex.
Professor Klein's report was as follows :—
St. Bartholomew's Hospital, E.C.,
19th September, 1902.
I beg herewith to report on the experimental analysis of twenty-four
samples of Milk delivered here by your Inspectors, in batches of six samples, on
the following dates :—
Nos. 1, 2, 3, 4, 5, 6 on July 15th, 1902.
Nos. 7, 8, 9, 10, 11, 12 on July 22nd, 1902.
Nos. 13, 14, 15, 16, 17, 18 on August 20th, 1902.
Nos. 19, 20, 21, 22, 23, 24 on August 27th, 1902.
The samples were all contained in sterile bottles supplied by me.
With the exception of sample No. 17, which was devoid of cream, all others
look normal milk.
The examination was in all instances carried out in order to detect the bacillus
tuberculosis. For this purpose, of each sample 250 cubic centimetres were placed
for 24 hours in the ico chest. After this time the whole of the sediment was
collected and used for the injection of two guinea-pigs : one [uneven number]
intraperitoneally, the other [even number] subcutaneously ; therefore 48 guineapigs
in all were experimented with, all the even numbers indicating the subcutaneous,
all the uneven numbers peritoneal injections. The animals were kept for from
between three to four weeks, and then a careful post-mortem was made of each, in
order to detect any abnormal condition, either locally or generally.
The use of two animals for each sample has proved of great use, not only in
enabling one to test a large amount of the milk sediment, but also on account of
making provision against accident in this manner. It not unfrequently has happened—and
the same occurred also in the present examination—that a guinea-pig,
after receiving such a considerable amount of milk sediment as is used in these
experiments, succumbs from an acute septicæmic infection. My experience of
analysis of milk for tubercle is very considerable, having within the last three or
four years examined more than 300 samples, and in all this time I have not known
a single instance when both the subcutaneously and the intraperitoneally-injected
guinea-pig [for one particular sample] succumbed from acute infection ; when
acute infection occurred it always affected one only of the two animals used for the
particular sample, so that one animal at all events remained for the tubercle test.