139 



as effectually to exclude the air, and then opening 

 an artery in the neck, he found that the blood which 

 issued from it was black : and he farther remarked, 

 that in a strangulated animal, where the entrance of 

 air was precluded, the blood in the left side of the 

 heart was like to venal blood ; but if, before it coa- 

 gulated, it was forced through the lungs, and air 

 was .at the same time blown into those organs, it a- 

 gain became florid, after the death of the animal, 

 in the same manner as when he was alive *. Mr 

 Hunter, by means of a double bellows, was enabled 

 by one action to exhaust the lungs of their air, and 

 by another to pass, at the same time, fresh air into 

 those organs, without mixing the two together ; and 

 having introduced the nozzle of his bellows into the 

 trachea of a dog, whose heart and lungs had been 

 previously brought into view, he found, that, while 

 he continued the artificial breathing, the heart con- 

 tinued to act as before, but more frequently : if, 

 however, he stopped the motion of the bellows, the 

 contractions of the heart gradually became weaker, 

 and at length ceased. On recurring to the artificial 

 breathing, the heart again began to move, and be- 

 came at length as strong as at first. This process 

 he repeated ten times, stopping from five to ten mi- 

 nutes between each ; and he observed, that every 

 time he left off working the bellows, the heart be- 

 came extremely turgid with blood, and that the 

 blood in the left side was as dark as that in the 

 right, which was not the case when the bellows were 



*Tractat. de Corde, p. 



