PARACENTESIS THORAGIS. 295 



fore proper to try to ascertain, by the following experiments, 

 the effects of a simple wound of the lungs, and the effects of 

 air confined in the thorax ; and the rather as, in some of these 

 cases, the wound of the pleura and intercostal muscles appeared 

 so large, that it might be doubted whether the air could be 

 confined in the chest, when there seemed to be so free a pas- 

 sage from that cavity into the cellular membrane. . 



EXPERIMENT I. 



I took a rabbit, and, pulling the skin of its chest to one 

 side, I pushed a sharp knife into the cavity of the thorax, and 

 moved it about so that I might wound the lungs ; then with- 

 drawing the knife, I let the skin slip back again, by which 

 means the wound of the skin was at some distance from that 

 of the intercostal muscles ; then applying a piece of lint, a 

 plaster, and a slight bandage to the wound of the skin, I ex- 

 pected to see the animal become emphysematous, but was dis- 

 appointed; and though I repeated the experiment three or 

 four times, I could not get the air to pass from the lungs into 

 the cellular membrane. On killing the animal, I observed 

 that the wounds of the lungs were surrounded by a small 

 ecchymosis, and were so closed (probably by the blood which 

 had been effused) that no air could escape. 



EXPERIMENT II. 



Having pushed a sharp knife into each side of the chest of 

 a dog, with the same precautions, and with the same intentions 

 as mentioned above, I then allowed him to run about the 

 house. This experiment I made at eight o'clock in the morn- 

 ing; about ten he appeared less lively, and about twelve seemed 

 to choose to be at rest, but had no difficulty of breathing nor 

 emphysema. In the evening he was as lively as before; and 

 was likewise so the next morning at eight o'clock, when I 

 killed him. On opening his abdomen, the diaphragm was not 

 depressed nor loose, as when air is let into the chest, nor did 

 any air escape on puncturing it. On opening the chest and 

 examining the lungs, I found that the wounds were small and 

 perfectly closed with a slight ecchymosis surrounding them. 

 On blowing into the lungs, the air did not escape through the 

 wounds. 



