THE INQUIRY. 539 



had attended to the nature of the animals experi- 

 mented on, their results would have been less con- 

 tradictory ; and that the various tribes of carni- 

 vorous animals generate much less carbonic acid, 

 in proportion to the amount of oxygen consumed, 

 than herbivora. For example, it was found by 

 Allen and Pepys, that pigeons absorbed 16 per 

 cent, more oxygen than they expired in the form 

 of carbonic acid, and guinea pigs 20 per cent. 

 In the experiments of Berthollet, the difference 

 was 25 and 30 percent, in the rabbit and Guinea 

 pig ; while in those of Despretz, it was from 25 

 to 34 per cent, in the same species of animals. 

 But in the cat, dog, and hawk, Dulong found the 

 difference from 20 to 50 per cent; owing, as he 

 justly inferred, to the difference between the 

 chemical constitution of vegetable and animal 

 food. (Journal de Physiologic, 1823.) 



Dr. Edwards also states, from his own experi- 

 ments, that in guinea pigs and yellow hammers, 

 the difference was in the ratio of 100 to 82.26; 

 while in puppies it was as 100 to 53. He further 

 ascertained, that green frogs and lizards con- 

 sume much more oxygen than is returned in 

 the form of carbonic acid, (which Spallanzanj 

 had found to be the case in many of the lower 

 species of animals.) (Influence of Phys. Agents 

 on Life, p. 216, 218.) And Miiller informs us, 

 that in fishes, Treviranus found the difference to 

 vary from 50 to 75 per cent. 



