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33
SUMMARY.
From the foregoing results it will be seen that of the 39 samples of milk
tested for the presence of tubercle bacilli three samples proved by animal
experiment to have contained them, that is to say, nearly 8 (eight) per cent,
of the samples were capable of causing tuberculosis. At the same time it
has to be pointed out that whereas with each of the two samples No. 19 and
No. 33, tuberculosis was produced in both animals (peritoneal and subcutaneous),
with sample No. 23 only in one animal (subcutaneous) was this
result obtained, the peritoneally-injected guinea-pig remaining unaffected.
This result would indicate that in the last named sample (23) the tubercle
bacilli could not have been present in the milk in great numbers, certainly in
less numbers than in the other two samples (19, 33).
Looking at the foregoing description of results a condition is seen which,
although of less seriousness for the present, may hide danger which at other
times is liable to assume not inconsiderable proportions.

As will be seen from Table A, 19 samples were found to be clean and pure,
no result followed on their injection into animals; this would amount to 48.7
per cent. only. The samples were:—Nos. 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12,
15, 16, 17, 18, 26, 28, 37 and 39. But 20 samples could not be declared
clean and pure, as tested by their action on the animal body ; this would
mean that 51.3 per cent, of the samples contained impurities which caused
disease.
These 20 samples ranged themselves into three groups, namely :—
(а) Three samples, or about 8 per cent. (7.9 per cent.) causing
culosis: Nos. 19, 23, 33.
(б) Seven samples, or 17'95 per cent., causing suppuration due to
Staphylococcus pyogenes aureus: Samples Nos. 6, 14, 24, 25,
27, 32, 38. In all the animals which showed the suppuration
the Staphylococcus pyogenes aureus was recovered from the pus
in pure culture. It will have been noticed that the suppuration
was not in all instances present in both animals, sometimes in one
only of the two.