DISTINCTIVE CHARACTERS OF ORGANIZED BODIES. 21 



the minutest parts of Organized bodies, is a necessary condition 

 of their existence. 



4. Organized structures are further distinguished from In- 

 organic masses by the peculiarity of their chemical constitution. 

 This peculiarity does not consist, however, in the presence of 

 any elementary substances which are not found elsewhere ; 

 for all the elements of which Organized bodies are composed, 

 exist abundantly in the world around. This, indeed, is a 

 necessary consequence of the mode in which they are built 

 up ; for that which the parent communicates in giving origin 

 to a new being, is not the structure itself, but the capacity to 

 form that structure from materials supplied to it ; and it is 

 by progressively converting these materials to its own use, 

 that the germ develops itself into the complete fabric. JS~ow 

 out of about seventy simple or elementary substances which 

 are known to occur in the Mineral world, not above twenty 

 present themselves as constituents of Vegetable and Animal 

 fabrics ; and many of these occur there in extremely minute 

 proportion. Some of them, indeed, appear to be introduced 

 merely to answer certain chemical or mechanical purposes ; 

 and the composition of the parts which possess the highest 

 vital endowments is extremely uniform. They are nearly all 

 formed at the expense of certain " organic compounds," which 

 are made up of the four elementary substances, oxygen, hy- 

 drogen, carbon, and nitrogen ; and these elements appear to 

 be united, not as in the case of inorganic compounds, two 

 by two, or after the binary method, but all four together, 

 so as to form a compound atom of great complexity. Thus 

 common nitre is regarded as a binary compound of nitric acid 

 and potass, since it can be decomposed into those two con- 

 stituents and can be re-formed by their union; and in the 

 same manner, its nitric acid is a binary compound of nitrogen 

 and oxygen, whilst its potass is a binary compound of potassium 

 and oxygen. But neither albumen nor gelatine, which are 

 the principal materials of the animal tissues, can be resolved 

 into any two other substances, by the union of which it can 

 be re-formed ; and when once it has been decomposed by che- 

 mical agencies, no means known to the chemist can reproduce 

 it. Albumen can, in fact, be generated only by the living 

 Plant, at the expense of the carbon, hydrogen, oxygen, and 

 nitrogen, which it draws from the elements around; and 



