96
Inter-relativity of the Diseases of Animals and Man
for one can never tell exactly when the udder tissues will become infected;
and the milk a source of definite and terrible danger to the children to whom
it is given.
Pasteurization, undoubtedly, offers some safeguard, but it is generally
admitted that some of the valuable properties which raw milk possesses are
lost during this process, and there can be no doubt that the best solution of
the prevention of infection lies in the endeavour to obtain an absence of the
tubercle bacilli at the source of supply—i.e., the dairy herd. That this can be
accomplished, if pecuniary and other necessary adjuncts are available, has
been proved by actual experiments, and America has been especially go-
ahead in her endeavours to form accredited herds. In that country whole
districts have been cleared, and the most stringent laws are enforced in order
to prevent reinfection by the entrance of tuberculous beasts into these areas.
In Great Britain progress in this direction has been slow; as the Bri-
tish public, although not unmindful of the advantages of tuberculosis-free
milk, is not willing, as a body, to pay an extra price for this guarantee. Dairy-
men who have gone to the expense and trouble of clearing their herds have
not received the encouragement they deserve either from the general pub-
lic or from the hospitals and medical practitioners. These last, in particular,
might do a very great deal more than they are doing to assist in educating
the housewives and mothers of young children as to the dangers of tuber-
culous milk, by urging upon them the necessity for demanding a clean milk
supply, i.e., one from tuberculin-tested cows.
This matter is now being seriously taken in hand, and a Veterinary
State Service has been formed, with a staff of whole-time men whose duties
consist mainly of the inspection and testing of dairy cattle, with a view to the
formation of tuberculosis-free herds. A clinical inspection is made of the
udders periodically, usually four times a year, and for the owner who wishes
to ensure that his herd is completely free from tuberculosis, the cows are tested
with tuberculin—of which we now have a synthetic variety—and by the '
intradermal method which forms a much more delicate test than the former
subcutaneous method. We have reason to hope that this newly formed
Veterinary State Service is thoroughly justifying its existence and that it will
prove of benefit not only to human beings, by getting rid of a source of tuber-
culous milk, but also to the dairyman and the agriculturist, by weeding out
from his herds tuberculous cattle whose presence is always a source of
danger. It is a common observation that the herds from which tuberculosis has
been eliminated are much more resistant to other ailments—the services of
the veterinary surgeon being less in demand than when this disease existed.
MANGE
Mange of the horse is now dealt with in all parts of Great Britain and is
compulsorily notifiable under a Mange Order issued from the Ministry of
Agriculture and Fisheries. Its spread has been effectually checked, and al-
though it is not yet completely eradicated, the number of cases in the horse