730 
ED. NOCARD. 
also tuberculosis, but the recovered animals may again take the 
disease as if they had never had it; therefore it is difficult to see 
how immunization can be obtained. But if we cannot hope to 
render animals refractory, we can at least with tuberculin and 
mallein make an early diagnosis of those diseases, when the an¬ 
imals have only the germ and when no external sign indicates 
their existence. We can then isolate them and arrest the prog¬ 
ress of the disease. It is upon the separation of the diseased that 
all the prophylaxy of these serious affections rests. 
I shall not insist any longer upon those points which have 
already been treated at length here, in the Congress of 1885. 1 
wish only to mention a new example of the efficacy of separ¬ 
ation. 
Some years ago I was called to apply tuberculin on a num¬ 
ber of Durhams. It was very interesting because the owner 
had shown himself a great adversary of the method. It had 
been severely criticised. At a given time, however, he asked me 
to apply the test on his stock. The results were positive. Out 
of 51 animals 27 could certainly be pronounced t'Uberculous and 
3 were doubtful; more than 50 per cent, of the herd. Some of 
the animals were killed, and the post-mortem having confirmed 
the diagnosis, the owner confessed his error, and was willing to 
have what was necessary done. The healthy animals were then 
separated from the sick and kept in another stable. 
According to the doctrine of non-heredity of tuberculosis 
the calves born of tuberculous cows were to be kept separate 
•from their mothers ; the correctness of this theory was fully jus¬ 
tified, as in three years none of the animals born of tuberculous 
mothers, 23 in number, have become diseased. As an instance, 
here is an establishment infected seriously which in less than 
. three years has returned to the original number of animals with¬ 
out the necessity of purchasing a single animal from outside. 
This is what can be obtained if it is wanted. It is for you to 
appreciate and recommend it. 
I do not overlook the fact that in practice the general appli¬ 
cation of those measures is full of difficulties. However, it is 
