296 OPERATION OF THE 



From these experiments I concluded that, in order to let 

 the air out of the lungs into the cavity of the thorax, a punc- 

 ture or incision (on account probably of the effusion of blood 

 from the divided vessels) was improper ; and that, in the em- 

 physematous cases above mentioned, the emission of the air 

 must have happened from a superficial abrasion, or laceration 

 of the part. 



EXPERIMENT III. * 



I tried, by pushing a blunt probe into the chest of a rabbit, 

 and by moving it about, to produce such an emphysema by 

 laceration, but without effect. 



EXPERIMENT IV. 



I then punctured the chest of another rabbit, but so cau- 

 tiously as not to hurt the lungs ; and, having blown into it, I 

 immediately made a compression upon the wound with some 

 lint, a compress, and a bandage, in order to confine the air in 

 the cavity of the thorax. I then observed that the animal 

 breathed more frequently and laboriously. On removing the 

 compress, the air rushed out, and the animal gradually re- 

 covered its natural manner of breathing. It was then allowed 

 to run about the house for a few days, and seemed not the 

 worse for the operation. 



EXPERIMENT V. 



The same experiment was repeated on a dog, after tying him 

 down to a table ; but, when the air was blown into the thorax, 

 he struggled so much, and acted so strongly with his chest, as 

 to force it out again almost immediately; so that not being 

 able to manage him, I was obliged to desist without having 

 had an opportunity of observing what alteration was produced 

 on his breathing. I kept him about a week, and did not ob- 

 serve him at all affected by the wound. 



I made no further experiments, being indeed almost con- 

 vinced from these that it was the air confined in the cavity of 

 the thorax, which had occasioned the violent symptoms in the 

 cases mentioned above, and not the mere wound of the lungs ; 

 and I must own, that if I was not perfectly convinced, it was 

 because no air, in such cases, had yet been found in the cavity 



