358 
EXPERIMENTS ON PLEURO-PNEUMONIA. 
eluding that, whatever may havebeen its antecedents, it was free 
from pleuro-pneumonia during the time that it was under 
observation. 
The remaining seven animals were, as has been already 
reported to the Society, exposed to the infection of pleuro¬ 
pneumonia in the most effectual manner that could be^devised. 
They were removed from the Brown Institution, and placed 
in sheds which were at the time occupied by diseased animals, 
and in stalls in which such animals had stood. They remained 
under these conditions for three months, and in some in¬ 
stances for four, after which they were kept under observation 
for periods which in the majority of the cases extended to six 
months. None of them showed any signs of infection. In 
those that were slaughtered the lungs and other internal 
organs were found to be perfectly healthy. 
The other six animals were inoculated early in the present 
year; but in consequence, first of our being unable to meet 
with cases of pleuro-pneumonia in situations convenient for 
our purpose, and subsequently of the obstacles imposed by 
legislation, all attempts to test the immunity of these animals 
in an effectual manner proved unavailing; and I found myself 
obliged to recommend to the Committee that they should be 
sold. 
The results of the experiments have been so far satisfactory 
that I cannot help regretting that they have been brought to 
an abrupt termination. The smallness of the number of the 
animals which we have had the opportunity of experimenting 
on renders it impossible to regard them as conclusive. The 
utmost that can be said is that, so far as they have gone, the 
results are sufficiently favorable to justify us in recom¬ 
mending further trial of the practice of venous infusion to those 
who are unlucky enough to have their herds invaded by pleuro¬ 
pneumonia. As regards the safety of the operation itself, I 
can speak with confidence. Provided that an operator can be 
found with sufficient dexterity to perform it, and sufficient 
conscientiousness to avoid the known sources of danger, the 
trial can be made without risk. Certainty as to its value can 
only be attained by the experience of some years. 
I cannot conclude this report without pointing out that, in 
case the value of inoculation should be established, there is no 
reason why the measures of sanitary police which have been 
enforced by the Legislature should interefere with its useful 
employment. It has been distinctly recognised as the basis 
of this legislation that pleuro-pneumonia is a disease of ex¬ 
tremely long incubation— i.e. one which may exist and pro¬ 
gress in the organism for months without producing obvious 
