468 M. Dumas on the Chemical Statics of Organized Beings. 



principles between the living engine and the other ; for if we 

 allow for all the inevitable losses in steam-engines which are 

 so carefully avoided in the human machine, the identity of 

 the principle of their respective powers appears manifest and 

 clear. 



But we have followed far enough considerations as to which 

 your own reflections are already in advance of me, and where 

 your recollections leave me nothing more to do. 



To sum up, then, we see that of the primitive atmosphere 

 of the earth three great parts have been formed : 



One which constitutes the actual atmospheric air; the se- 

 cond, which is represented by vegetables, the third by animals. 



Between these three masses, continual exchanges take place: 

 matter descends from the air into plants, enters by this route 

 into animals, and returns to the air according as these make 

 use of it. 



Green vegetables constitute the great laboratory of organic 

 chemistry. It is they which, with carbon, hydrogen, azote, 

 water and oxide of ammonium, slowly build up all the most 

 complex organic matters. 



They receive from the solar rays, under the form of heat 

 or of chemical rays, the powers necessary for this work. 



Animals assimilate or absorb the organic matters formed 

 by plants. They change them by little and little, they de- 

 stroy them. In their organs, new organic substances may 

 come into existence, but they are always substances more sim- 

 ple, more akin to the elementary state than those which they 

 have received. By degrees these decompose the organic 

 matters slowly created by plants ; they bring them back 

 little by little towards the state of carbonic acid, water, azote 

 and ammonia, a state which allows them to be returned to 

 the air. 



In burning or destroying these organic matters, animals 

 always produce heat, which radiating from their bodies in 

 space, goes to supply the place of that which vegetables had 

 absorbed. 



Thus all that air gives to plants, plants give up to animals, 

 and animals restore it to the air, an eternal circle in which 

 life keeps in motion and manifests itself, but in which matter 

 merely changes place. 



-The brute matter of air, organized by slow degrees in 

 plants, comes, then, to perform its part without change in ani- 

 mals, and serves as an instrument for thought ; then van- 

 quished by this effort and broken, as it were, it returns brute 

 matter to the great reservoir whence it came. 



Allow me to add, in finishing this picture, which sums up 



