THE DISEASES OF CATTLE. 47 



by a transmutation no less true than surprising, these matters, 

 ready formed, pass from vegetable to herbivorous animals, and 

 then to carnivora, which either consume or preserve them, ac- 

 cording to their wants. Lastly, either during the life of such 

 animals, or after their death, these organic matters, in the ratio 

 in which they become consumed, return to the atmosphere 

 whence they are derived ; and thus is formed the organic circle 

 of organic life upon the surface of our globe. 



" The air contains or generates certain oxyde productions, 

 carbonic acid, water, azotic acid, oxyde of ammonia. Plants, 

 the veritable decomposers of these, absorb their bases, carbon, 

 hydrogen, azote, and ammonia, with which elements they com- 

 pound the whole of the matters, organic and organizable, 

 yielded to animals. These veritable apparatus for combustion, 

 in their turn, reproduce carbonic acid, water, oxyde of ammo- 

 nia, and azotic acid, which once more depart into the air, in 

 order to regenerate afresh, through endless ages, the same phe- 

 nomena. 



" To this picture, striking no less by its si mplicity than its 

 grandeur, we must add the undeniable influence of solar light, 

 which alone can set in action this immense apparatus of the 

 vegetable kingdom, whence is effected the reduction of the 

 oxyde ingredients of the air to serve the purposes of the for- 

 mation and repair of organization. 



" So that modern chemistry has traced, with admirable pro- 

 fundity, the important part performed by the air, the grand 

 agent, this immense reservoir, which, by itself, or through the 

 agency of the substances contained in it, furnishes the primary 

 elements of vegetable organization. Here, then, is the pri- 

 mary form of the constituent elements of living bodies (to wit) 

 the gaseous state. It is likewise through the same state that 

 comes their end. 



*' But it is not only at their formation, or at their decay, that 

 their immediate principles become resolved into gas ; the same 

 thing happens in the course of their lifetime. Even in their 

 very tissues gas becomes developed, and commonly as the pro- 

 duct of secretion ; only such products are not generated in any 



