502 Dr. Davy’s observations and experiments 
the bladder. The exact quantity of air retained was not 
determined ; it must have exceeded at least ten cubic inches. 
As speedily as possible the cannula was withdrawn, and the 
external wound carefully closed by suture. The health of 
the dog was very little impaired by this operation. Two days 
after, when the animal appeared to be quite well, a similar 
experiment was made on the left side of the chest, and a 
mixture, consisting of 75 parts common air and 25 carbonic 
acid gas, was introduced into the pleura. This operation had 
very little more effect than the former. At the end of 24 hours 
the dog was killed, and immediately examined. 
About 3 cubic inches of air only were procured from the 
left pleura, which were found to consist of 
18.3 carbonic acid gas, 
78.3 azotic gas, 
3.4 oxygene gas : 
whilst the air admitted consisted of 
20.0 carbonic acid gas, 
63 . 2 azotic gas, 
16.8 oxygene gas : — - 
Thus apparently showing, that during a sojourn of three 
days in the pleura, the oxygene had been absorbed in a 
greater degree than the carbonic acid gas, and the latter in a 
greater degree than the azote. The result of the experiment 
on the left pleura was very similar ; it afforded ten cubic in- 
ches of gas, consisting of 25 carbonic acid gas, 70 .6 azotic 
gas, and 4.4 oxygene gas. The appearances on examining 
the wounds were satisfactory : the cavity of the chest was 
free from inflammation, the lungs uninjured, and the cicatrix 
in the pleura only just perceptible. 
