WOUNDS PENETRATING INTO THE CHEST. 633 
trefy. All the tissues with which it is in contact are stained of 
a deep red colour, and almost always pleurisy and pneumonia 
develope themselves in the neighbourhood of the altered mass. 
In the greater part of the cases of actual practice, and of a 
practice of considerable extent, the consequences of communica-* 
tion with the external air are not so serious, and they differ ma¬ 
terially according to circumstances; for we have remarked in the 
course of our experiments, and when studying the effect of 
wounds made with cutting instruments, that when the air had 
access only momentarily, the clot successfully isolated itself and 
did not putrefy, and consequently could be absorbed in a greater 
or less length of time. Therefore it is that we are always so 
anxious to cut off all communication between the interior of the 
chest and the air without. 
6. Simple wounds of the parietes of the chest , with effusion of 
blood , a counter-opening, and the introduction of air . 
After having produced bloody effusion in the chest, by making 
the contents of a divided artery run into it, we have almost imme¬ 
diately afterwards made a counter opening at the inferior, and 
very lowest part of the chest. No blood flowed through this 
opening, the lips of which remained close to each other. We 
have then separated the edges of the wound by plunging a seton 
needle into the chest, and making the broad side of the needle 
perpendicular to the sides of the wound. It has not even then 
escaped, but only a few drops of a red liquid which was not pure 
blood. 
This experiment was made at the abattoir of Montfau§on, 
where we were enabled to destroy the horse a quarter of an hour 
after the injection of the blood. We examined the cavity of 
the chest twenty-five minutes after the blood was thrown in. It 
was already coagulated—the clot was very large, flattened, and 
applied by its two surfaces against both the pulmonary and costal 
pleura. The coagulation had probably already taken place when 
the puncture was made, since the counter-opening was not fol¬ 
lowed by the escape of any blood. 
The same experiment was made upon a horse which we de¬ 
stroyed six days after the injection of the blood, and after the 
introduction of some air through the counter-opening. VV e did 
not find any trace of the injected blood. 
The introduction of the air did not in these experiments pro¬ 
duce any marked effect, because, without doubt, the communi¬ 
cation of the atmosphere with the cavity of the chest was only 
momentary, or of very slight duration. 
We made another analogous experiment, by injecting into the 
chest six pounds of blood, which we had that instant drawn 
YOL. VII. 4 N 
