Vaccination of Cattle against Tuberculosis. 139 
(2) that the animal enters into possession of immunity 
immediately. Its chief defect is that the protection which it 
confers does not last more than a fortnight, and to this has to 
be added the fact that the serum is rather more expensive than 
the “ vaccins,” which are used in the ordinary Pasteurian 
method of vaccinating. The new method, in spite of these 
drawbacks, may be recommended as a means of cutting short 
outbreaks, where, from carelessness in dealing with the carcass 
of a first case of anthrax, or from any other cause, there is reason 
to fear that a number of the survivors have already become 
infected, although they have not yet developed any symptoms 
of the disease. Furthermore, experience which has been gained 
abroad indicates that the life of an animal already showing 
symptoms may sometimes be saved by giving one or more large 
doses of the serum. 
Vaccination of Cattle against Tuberculosis. 
It is a fact familiar to every one that in the case of 
certain diseases, both of man and the lower animals, recovery 
from a first attack makes it highly improbable that the 
individual will at any subsequent time become affected 
with the same disease. This is true, for example, of human 
beings who have survived an attack of small-pox or scarlatina, 
of cattle which have recovered from cattle-plague, and of 
horses which have suffered from strangles. There are, on 
the other hand, certain bacterial diseases from which the 
same individual may suffer repeatedly, the first attack leaving 
the patient almost or quite as susceptible to infection as 
before. Only a few years ago it was the universal opinion, 
both among medical men and veterinary surgeons, that 
tuberculosis belonged to the latter class of diseases, it being 
generally held that recovery from a first attack left the 
individual with all his original susceptibility, or even with 
diminished power of resisting infection. From this it followed 
as a corollary that it was hopeless to expect the discovery 
of any useful method of vaccinating animals against 
tuberculosis. 
In a previous Annual Report (Journal, Vol. 63, 1902, page 
264) it was pointed out that this opinion appeared to have been 
formed on quite inadequate grounds, and a number of experi- 
ments were described which went to show that recovery from 
a first attack of tuberculosis left cattle with increased powers 
of resisting infection, and that it was possible to confer on 
cattle a very high degree of immunity against the disease. 
Since the date of that Report (1901), and especially during 
the last two vears, the immunisation or vaccination of cattle 
against tuberculosis has been the object of numerous 
