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Concluding Report on the Experiments at the 
reason for recommending it as a practice, unless it can be shown 
that the third question — that which relates to the risk of the 
operation itself — admits of a satisfactory answer. On the 
ground of its danger the French Commission, notwithstanding 
their opinion as to its protective power, declined to recommend 
it as an economically advantageous practice ; for they considered 
that their own experiments showed " that inoculation causes a 
larger mortality than the disease which it is intended to pre- 
vent." No less than 11 per cent, of their animals had died7 
whereas it was extremely improbable that so large a number 
would have been sacrificed had they been subjected without 
inoculation to the ordinary risks of infection. Notwithstanding 
these facts, the Commission, of which M. Bouley was the 
Secretary, recommended that it ought to be encouraged on the 
ground that, its protective power having been demonstrated, the 
dangers above referred to would be diminished by improved 
methods. 
Inoculation is usually performed by inserting the liquid which 
drains from diseased lungs into the cellular tissue. The situa- 
tion chosen for the purpose is the end of the tail. The reason 
why this part is selected is, that if, as often happens, the local 
inflammation becomes excessive, it may be limited by amputa- 
tion. But notwithstanding this safeguard, the diseased action 
is apt to spread to the neighbouring parts, in which case it 
occasions serious illness and often death. 
The position of the question was therefore clear. The pro- 
tective power of inoculation, though by no means definitively 
settled, had been rendered sufficiently probable to justify a more 
extended trial than it had as yet received. But the effects of the 
operation as hitherto practised were sometimes so severe that it 
appeared probable that the risk would more than cover the 
advantage. 
One of the first objects which we had in view in our experi- 
ments was to test the possibility of communicating pleuro- 
pneumonia by mediate contagion. The lungs of animals which 
had been slaughtered in an advanced state of the disease (see 
Appendix I.) were placed, in the fresh state, under the noses of 
ten healthy animals of all ages. As none were infected, it did 
not seem necessary to repeat the trials in a systematic marnier, 
the more so as the persons who attended on the animals were 
in the habit of handling the diseased organs which were at 
that time frequently brought to the Institution for pathological 
examination. 
The experiments on inoculation were commenced in September 
in 1876. The first practical question which required an ans.wer 
was whether it was possible by taking extra precautions in the 
