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.—Now 
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 
imto any two other substances, by the union of which it can 
s re-formed ; and when once it has been decomposed by che- 
nical 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 
trogen, which it draws from the elements around; and 
