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tinct the one from the other and never becoming changed the one into the other, we should have no need
to enlarge appreciably our conception of the extent to which the human body is subject to bovine tuberculosis.
Such cases of admixture must be few and their effect slight; bovine tuberculosis in the human
body would practically be limited to cases such as those which furnish Group I. Should, however,
it be conclusively proved that a eugonic bacillus of low virulence may be modified under certain conditions
into a dysgonic bacillus of high virulence and vice versa, our views as to the relation of human
to bovine tuberculosis must be very different. Such a conclusion would lead to the following view. Bacilli
from a bovine source entering a human body in scanty numbers may become lodged there without
immediately provoking a generalised progressive tuberculosis. During their sojourn there they may
become modified into eugonic bacilli of low virulence; and they may then give rise either to a limited
tuberculosis only, or, under the influence of certain conditions, to a generalised progressive tuberculosis.
For some time after the change they may remain unstable and capable of reverting to their bovine
character under changed conditions, when subjected, for instance, to the influence of bovine tissues,
as in the passage experiments. Or after a long stay in the human body their character may become
so fixed that they cannot be distinguished from bacilli conveyed directly from man to man."
The conclusions of the Commission are as follows:—
There can be no doubt but that, in a certain number of cases, the tuberculosis occurring in the human
subject, especially in children, is the direct result of the introduction into the human body of the bacillus of bovine
tuberculosis, and there also can be no doubt that in the majority at least of these cases the bacillus is introduced
through cows' milk. Cows' milk containing bovine tubercle bacilli is clearly a cause of tuberculosis and
of fatal tuberculosis in man.
Of the sixty cases of human tuberculosis investigated by us, fourteen of the viruses belonged to Group I.,
that is to say, contained the bovine bacillus. If, instead of taking all these sixty cases, we confine ourselves to
cases of tuberculosis in which tho bacilli were apparently introduced into the body by way of the alimentary
canal, the proportion of Group I. becomes very much larger. Of the total sixty cases investigated by us, twentyeight
possessed clinical histories indicating that in them the bacillus was introduced through the alimentary canal.
Of these, thirteen belong to Group I. Of the nine cases in which cervical glands were studied by us, three, and of
the nineteen cases in which the lesions of abdominal tuberculosis were studied by us, ten belong to Group I.
These facts indicate that a very large proportion of tuberculosis contracted by ingestion is due to tubercle
bacilli of bovine source.
A very considerable amount of disease and loss of life, especially among the young, must be attributed to
the consumption of cows' milk containing tubercle bacilli. The presence of tubercle bacilli in cows' milk can be
detected, though with some difficulty, if the proper means be adopted, and such milk ought never to be used as
food. There is far less difficulty in recognising clinically that a cow is distinctly suffering from tuberculosis, in
which case sho may be yielding tuberculous milk. The milk coming from such a cow ought not to form part
of human food, and indeed ought not to be used as food at all. Our results clearly point to the necessity of
measures, more stringent than those at present enforced, being taken to prevent tho sale or tho consumption of
such milk,
Cancer.
The deaths from cancer in the Administrative County of London during 1906 (365 days)
numbered 4,589.
The death-rates from this disease in successive periods have been as follows

For the purpose of enabling the incidence of cancer on the several populations of the sanitary
areas to be more precisely stated, factors have been calculated for correcting the death-rates, as far
as possible, for differences in the age and sex constitution of the several "populations concerned.
These factors are shown in the following table, together with the death-rates for each sanitary area,
corrected by their application. Owing to the changes of area in the sanitary districts of London
caused by the London Government Act of 1899, the death-rates since 1900 are the only figures
available for comparative purposes, but it can be seen from these figures that differences in
the age and sex constitution of the population are partially responsible for the differences in
the crude death-rates obtaining in the several districts.
1 See footnote (2), page 7.