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"cated with the atmosphere. The tubes were large, 

 and valves, made out of an allantoid, were affixed to 

 the end of the upright tube, and to that attached to 

 the allantoid, so that the air, when expelled from 

 the lungs, should not escape into the atmosphere, 

 nor return from the allantoid, after having once en- 

 tered it. Precautions were taken also, by covering 

 the mouth and nostrils, to prevent any air from pass- 

 ing in or out of the lungs, except by the tubes above 

 mentioned. Things being thus prepared, he began 

 to respire, and did not remove his mouth from the 

 tube till he had filled the allantoid, taking care to 

 stop his nostrils during expiration. The allantoid 

 was filled, in repeated trials, by about 56 expira- 

 tions, as natural as possible ; and as its capacity was 

 240O cubic inches, the average bu.lk of air thrown 

 out of the lungs by each expiration, was 42.8 cubic 

 inches. He then fixed another allantoid, whose ca- 

 pacity had been previously ascertained, to the end 

 of the upright tube ; and having filled it with at- 

 mospheric air, he inspired the air from one allantoid 

 and expired it into the other, and the quantities were 

 found to be nearly the same. Several persons of the 

 middle size repeated this experiment with nearly the 

 same result ; the difference being scarcely ver more 

 than one or two cubic inches. By another mode of 

 experiment, first proposed by Boerhaave, of plun- 

 ging a man into a tub of water up to his chin, and 

 judging of the dilatation of the lungs from the as- 

 cent and descent of the water, he obtained, by seve- 

 ral trials, nearly the same results ; and when these 

 same men were made to breathe from and into the 

 allantoids, in the manner above described, the cor- 



