INOCULATION FOR PLEURO-PNEUMONIA IN CATTLE. 163 
“ removes” from the original source of the inoculating material, 
is also another very important question. The lymph of the 
vaccine disease, small-pox, &c., is made milder and safer for 
use by these removes ; and supposing the truth of the system 
of inoculating cattle, as a preventive of pleuro-pneumonia, to 
be established, it is of the first importance that a safe as well 
as an efficacious material should be employed. These points 
will undoubtedly receive elucidation by the experiments now 
being adopted at the several Continental schools of veteri- 
nary medicine. It is a question, however, well worthy the 
attention of the Council of this Society, as to whether any 
efforts should be made here towards an obtainment of infor- 
mation on such important subjects. We are told that these 
problems are solved, and that experience has confirmed the 
truth of the conclusions ; but, at the least, 1 can affirm from 
my own observations that the practice of the inoculators does 
not bear out their assertions, nor is it conducted as though 
these things were known. 
Dr. Willems says he has carried “the virus” through five 
removes, and that no deaths and fewer casualties arise from 
the operations made with the product of such inoculations, 
and yet, strange as it may appear, he unhesitatingly asserts 
that he prefers the original exudations from the diseased 
lungs. Nay, of this I had plenty of proof, as upwards of 
thirty newly-purchased animals were allowed to remain un- 
inoculated for upwards of a week, until he could obtain some 
fluid directly from the affected lungs of an animal destroyed 
by the malady. Another instance of the same kind was 
afforded me two days before leaving Belgium, when I accom- 
panied M. Willems from Hasselt to the Veterinary School of 
Brussels, where eight cows sent by the Government, in ad- 
dition to those before mentioned, were waiting his operations. 
On the morning of our arrival a cow had died of pleuro- 
pneumonia, from which he inoculated these animals, and rtf- 
inoculated two of those I had seen at my first visit. M. 
Willems promised to send me the result of these experiments, 
and has done so in as far as the eight cows are concerned, 
but has omitted to say one word about the reinoculated animals. 
With reference to the period of incubation of “the virus,” 
it is said to vary from ten days to a month, but I am of 
opinion that no correct data can be obtained on such a 
subject from the rough and unscientific operations I wit- 
nessed. It is, perhaps, right I should here state that the 
Professors of the Brussels School are only the observers of 
the practice, the Minister wishing M. Willems to act inde- 
pendently, and to report when the animals are in a condition 
to be subjected to counter-proofs, such as cohabitation with 
