370 



RESPIRATION. 



Spallanzani also found that even the egg-shells alone absorbed a 

 little oxygen and exhaled carbonic acid a circumstance, however, 

 which presents a much closer analogy with the decomposition of 

 other substances, such as fibrin, &c., than with the respiration. 



In considering the respiration of the amphibia^ we shall merely 

 refer to the experiments of Regnault and Reiset (notwithstanding 

 the admirable observations of Marchand, which we have frequently 

 noticed), as their results could alone furnish us with numbers 

 admitting of comparison with the above tables, in as far as they 

 have been obtained by one and the same method. In all main 

 points, however, these observers perfectly agree with one another. 



We find, even amongst the amphibia, that the more active 

 creatures exhibit greater rapidity in the metamorphosis of matter, 

 and therefore consume more oxygen and exhale more carbonic 

 acid and nitrogen, than the more sluggish animals, in which there 

 is a less active metamorphosis of matter. This relation is very 

 strikingly shown, in the above table, between lizards and frogs. 

 This requirement of the amount of the respiration is further con- 

 firmed by certain experiments made on lizards ; in the first experi- 

 ment the animals were perfectly rigid, in the second they were not 

 entirely rigid, and in the third, the results of which are given in 



