444 RESPIRATION. 



The experiments of Regnault and Reiset, to which fre- 

 quent reference has been made, have a most important bear- 

 ing on the question under consideration. As these observers 

 were able to carefully measure the entire quantities of oxygen 

 consumed and carbonic acid produced in a given time, the 

 relation between the two gases was kept constantly in view. 

 They found great variations in this relation, mainly dependent 

 upon the regimen of the animal. The total loss of oxygen 

 was found to be much greater in carnivorous than in herbiv- 

 orous animals ; and in animals that could be subjected to a 

 mixed diet, by regulating the food, this was made to vary be- 

 tween the two extremes. The mean of seven experiments on 

 dogs showed that for every 1,000 parts of oxygen consumed, 

 745 parts were exhaled in the form of carbonic acid. In six 

 experiments on rabbits, the mean was 919 for every 1,000 

 parts of oxygen. 1 



In animals fed on grains, the proportion of carbonic acid 

 exhaled was greatest, sometimes passing a little beyond the 

 volume of oxygen consumed. 



" The relation is nearly constant for animals of the same 

 species which are subjected to a perfectly uniform alimenta- 

 tion, as is easy to realize as regards dogs ; but it varies not- 

 ably in animals of the same species, and in the same animal, 

 submitted to the same regimen, but in which we cannot reg- 

 ulate the alimentation, as in fowls." 2 



When herbivorous animals were entirely deprived of food, 

 the relation between the gases was the same as in carnivorous 

 animals. 



The final result of the experiments of Regnault and 

 Reiset was, that the " relation between the oxygen contained 

 in the carbonic acid and the total oxygen consumed, varies, 

 in the same animal, from 0*62 to 1*04, according to the regi- 

 men to which he is subjected." 



1 REGNAULT and REISET, Recherches Chimiques sur la Respiration. Annales 

 de Chimie et de Physique, 3me serie, tome xxvi. 



2 Ibid., p. 614. 



