366 



RESPIRATION. 



extent, be regarded as affording the normal numbers for the 

 excretion of carbonic acid in man, we subjoin his average relations 

 for one hour : 



According to Andral and Gavarret, an adult man exhales on an 

 average from 38*5 to 40'3 grammes of carbonic acid in an hour ; an 

 adult female, when not pregnant, from 22'0 to 23*8 grammes ; 

 during pregnancy, 29*3 grammes; and after the cessation of men- 

 struation, from 27*5 to 31-2 grammes. Although Scharling 

 included the products of perspiration with those of respiration, 

 while Andral and Gavarret included only the latter, their numbers 

 are yet higher than those of Scharling. It will be readily seen, 

 from the preliminary remarks which we made on this subject, that 

 the higher numbers obtained by Andral and Gavarret are solely to 

 be referred to the circumstance that in their experiments the 

 respiration was less natural, or at all events more frequent, than 

 in those of Scharling, who, by the use of a commodious apparatus, 

 was enabled to observe a more normal state of the respiration. 



Although there can be no doubt that the bodily constitution 

 influences the intensity of the respiration, we have no direct 

 observations in proof of this fact, unless indeed we include under 

 that head the fact noticed by Regnault and Reiset, that lean 

 animals consume more oxygen and exhale more carbonic acid than 

 very fat ones a result which can readily be brought into harmony 

 with the observation made by Schmidt and Bidder, that fat 

 animals excrete far less bile than lean ones. 



We now proceed to consider the differences which have been 

 observed in the respiration of different classes of animals ; for as 

 the greater number of the experiments made on the respiratory 

 functions have been instituted on animals, it is from them that we 

 must derive our most valuable results, more especially from the 

 experiments of Regnault and Reiset, who surpass all other 



