EXPERIMENTS ON PLEURO-PNEUMONIA. 
355 
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 whieh 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 
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 manner, 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 exami¬ 
nation. 
The experiments on inoculation were commenced in Sep¬ 
tember in 1876. The first practical question which required 
an answer was whether it was possible by taking extra pre¬ 
cautions in the collection of liquid, and particularly by using 
it only in an absolutely fresh state, to avoid the inflammatory 
results which have been above described. Five animals were 
inoculated with perfectly fresh material from a cow T -killed the 
same morning. A few drops of the clear exudation-liquid from 
the lungs were injected under the skin either of the shoulder 
or of the side of the neck. For five days the animals remained 
well; on the sixth day a swelling appeared at the puncture, 
which gradually increased. In three of the cases it began to 
subside a week after it had commenced, and eventually dis¬ 
appeared ; but in the other two it went on increasing until it 
had involved the integument of the neck, chest, and belly, at 
length causing death by general infection, in the one case on 
the twelfth, in the other on the fifteenth day of the illness. 
It is to be noticed that the animals exhibited no loss of appe¬ 
tite, nor any other sign of general disturbance, until the third 
or fourth day after the swelling appeared, nor did the tem¬ 
perature begin to rise in any instance until that time. In the 
two fatal cases, the highest temperature, four and a half degrees 
above the natural standard (106*4 Fahr.), was reached three 
days before death. 
The mode of progress of the illness indicated very distinctly 
that, although we had not communicated pleuro-pneumoniaby 
our inoculations, we had introduced an infection of another 
kind. If the liquid injected had been a mere irritant it would, 
if its action had been intense enough, have produced a limited 
abscess, not a rapidly-spreading and diffuse infiltration. That 
this was so was confirmed by the appearances observed after 
