542 RATIOS OF CARBON, HYDROGEN, ETC. 



species of matter, one of these must be the pri- 

 mary cause of vital action. And as it is now well 

 known that oxygen is the only gas capable of 

 supporting life by respiration, the question arises 

 whether it produces the effect by its immediate 

 agency, or by the evolution of an imponderable 

 fluid, as during the process of combustion. But 

 if the number, diversity, and specific character 

 of plants throughout the earth be determined by 

 the amount of caloric derived from the sun, it 

 follows a fortiori that the vital force of animals, 

 and the developement of their organization must 

 be regulated by the quantity of the same agent, 

 which I have shown to be the active principle in 

 light, electricity, oxygen, and all the other forms 

 of matter. Yet no regular and systematic attempt 

 has ever been made to connect the theory of 

 animal temperature with the laws of life, or the 

 phenomena of sanguification, secretion, nutrition, 

 sensation, volition, and muscular motion. 



If it can be shown that there is more carbon in 

 the venous than arterial blood of all animals, it 

 must be given off while passing through the lungs, 

 because it is found to be diminished immediately 

 afterwards. And if the proportion of carbon be 

 greater in the venous blood of herbivora than of 

 carnivora, it will explain why the former gene- 

 rate more carbonic acid in proportion to the 

 amount of oxygen consumed by respiration. 

 For the same reason, if the ratio of hydrogen be 



