M. Dumas on the Chemical Statics of Organized Beings. 339 



number, the formation of which is strictly connected with the 

 history of the air itself. Have we not, on the other hand, proved 

 that plants, in their normal life, decompose carbonic acid for the 

 purpose of fixing its carbon and of disengaging its oxygen; that 

 they decompose water to combine with its hydrogen, and to 

 disengage also its oxygen ; that, in fine, they sometimes bor- 

 row azote directly from the air, and sometimes indirectly 

 from the oxide of ammonium, or from nitric acid, thus working 

 in every case in a manner the inverse of that which is peculiar 

 to animals? If the animal kingdom constitutes an immense 

 apparatus for combustion, the vegetable kingdom, in its turn, 

 constitutes an immense apparatus for reduction, in which 

 reduced carbonic acid yields its carbon, reduced water its 

 hydrogen, and in which also reduced oxide of ammonium 

 and nitric acid yield their ammonium or their azote. 



If animals then continually produce carbonic acid, water, 

 azote, oxide of ammonium, — plants incessantly consume ox- 

 ide of ammonium, azote, water, carbonic acid. What the one 

 class of beings gives to the air, the others take back from it ; 

 so that to take these facts at the loftiest point of view of ter- 

 restrial physics, we must say that, as to their truly organic 

 elements, plants and animals spring from air, — are nothing 

 but condensed air; and that, in order to form a just and true 

 idea of the constitution of the atmosphere at the epochs which 

 preceded the birth of the first organized beings on the surface 

 of the globe, there must be placed to the account of the air, 

 by calculation, that carbonic acid and azote, whose elements 

 have been appropriated by plants and animals. Thus plants 

 and animals come from the air, and thus to it they return ; 

 they are real dependences of the atmosphere. 



Plants, thtn, incessantly take from the air what is given to 

 it by animals ; that is to say, carbon, hydrogen and azote, or 

 rather, carbonic acid, water and ammonia. 



It now remains to be stated, how in their turn, animals ac- 

 quire those elements which they restore to the atmosphere ; 

 and we cannot see without admiring the sublime simplicity 

 of all these laws of nature, that animals always borrow these 

 elements from plants themselves. 



We have, indeed, ascertained, from the most satisfactory 

 results, that animals do not create true organic matters, but 

 that they destroy them ; that plants, on the contrary, habitu- 

 ally create these same matters, and that they destroy but few 

 of them, and that in order to effectuate particular and deter- 

 minate conditions. 



Thus it is in the vegetable kingdom that the great labora- 

 tory of organic life resides ; there it is that the vegetable and 



Z2 



