232 ®^ '^"^ NONABSORPTrON OF OXIGEN IN RESPIRATION. 



unless fresli facts can be adduced, tliat may tend to decide 



the yjoint at issue. 



Theoxi^'en I would just obseri'e however, that J. F.'s mode of ae-* 



some case" of'^ Counting for the deficiencj' of the proportion of oxigen in 



respiration not the Uifit two experiments of Messrs. Allen and Pepj's quoted 



simpiy retained jj ^-^^ appears to be founded on an erroneous idea. Those 

 in the lungs. ,. . ... 



gentlemen did not ascertain the absolute quantitj' of oxigeii 



in the air after respiration, thej'' merely determined the pro- 

 portions of oxigen and carbonic acid to nitrogen in a given 

 quantity; consequently, whether the air left in the lungs 

 at the end of the experiment were more or less, this air 

 would have nearly the same proportions of oxigen, carbonic 

 acid, and nitrogen, as that in the gasometer; so that no 

 surplus in the lungs would account for the deficient propor- 

 tion of oxigen. 

 Thefmodeof There is another remark may be made on this^ subject, 

 conducting the T^lie operator, in the experiments of Messrs. Allen and' 

 experiment -r-w ■ i ^ • •• t ■ v r • i i 



shows thib. Pepys, draws the air into his lUngs trom one vessel through 



one tube, and then breathes it out through another tube 

 into another vt^ssel ; and this he continues to repeat a con* 

 siderable number of times, all communication between liis 

 lung;- and the external air being completely cut off both in 

 expiration and inspiration. Consequently all the loss of 

 quantity in the result, that can be ascribed to the lungs 

 being less completely emptied at one time than another, 

 must be the surplus, th.ii ibe hinws rettin after the last ex- 

 piration above what they retained after the expiration pre- 

 vious to commenciTig the experiment. In the third experi- 

 ment of Messrs. Allen and Pepys [see Journal, vol. XXII, 

 p. 183] this loss is only four cubic inch«s, which might be 

 ascribed to such a cause: but in several others it is upwards 

 of thirty, and in the eighth tiie loss is sixty-two cubic 



inches, which is surely mucli too great to be accounted for 

 Apparent mis- . , . _ • t i .. i , T»/r » n 



calculation of i" this way. I am inclined to suspect, that Messrs. Alien- 



Messrs. A. &P. m;jj Pepys themselves, when they ascribe the deficiency 

 " prinGipaTly to the impossibility of bringing the lungs to 

 the same state after forcible expiration" [ib. p. 187], di- 

 vided the quantity thus disappearing among the total num- 

 ber of expiratiotfti made; for this remark is introduced by 

 the following words: " The smallness of the deficiency 



[18 cub. 



