M. Dumas 07i the Chemical Statics of Orgmiized Beings. 365 



The neutral azotated substances, fibrin, albumen and ca- 

 seum, which are at first dissolved, and then precipitated, pass 

 into the chyle greatly divided or dissolved anew. 



The animal thus receives and assimilates almost unaltered the 

 azotated neutral substances which it finds ready formed in the 

 animals or plants upon which it feeds; it receives fatty matters 

 which come from the same sources ; it receives amylaceous 

 or saccharine matters which are in the same predicament. 



These three great orders of matters, whose origin always 

 ascends to the plant, become divided into products capable 

 of being assimilated, fibrin, albumen, caseum, fatty bodies, 

 which serve to renew or recruit the organs with the com- 

 bustible products, sugar and fatty bodies which res|)iration 

 consumes. 



The animal therefore assimilates or destroys organic mat- 

 ters ready formed ; it does not create them. 



Digestion introduces into the blood organic matters ready 

 formed ; assimilation employs those which are azotated ; 

 respiration burns the others. 



If animals do not possess any peculiar power for producing 

 organic matters, have they at least that special and singular 

 power which has been attributed to them of producing heat 

 without expenditure of matter ? 



You have seen, while discussing the experiments of MM. 

 Dulong and Despretz, you have positively seen the contrary 

 result from them. These skilful physicists supposed that an 

 animal placed in a cold water calorimeter comes out of it with 

 the same temperature that it had on entering it ; a thing abso- 

 lutely impossible, as is now well known. It is this cooling of 

 the animal, of which they took no account, that expresses in 

 their tableaux the excess of heat attributed by them and by all 

 physiologists to a calorific power peculiar to the animal and 

 independent of respiration. 



It is evident to me that all animal heat arises from respira- 

 tion; that it is measured by the carbon and hydrogen burnt. 

 In a word, it is evident to me that the poetical comparison of 

 a rail-road locomotive to an animal is founded on a more se- 

 rious basis than has perhaps been supposed. In each there 

 are combustion, heat, motion, three phaBUomena connected 

 and proportional. 



You see, that thus considering it, the animal machine be- 

 comes much easier to understand; it is the intermediary be- 

 tween the vegetable kingdom and the air; it borrows all its 

 aliments from the one, in order to give all its excretions to 

 the other. 



Shall I remind you how we viewed respiration, a phasno- 

 menon more complex than Laplace and Lavoisier had thought 



