186 DR ALISON’S OBSERVATIONS ON 
ing the germination of seeds, and in both these cases is useful as giving a 
greater degree of solubility to the starch whence it is formed. In both cases it 
disappears, and probably is converted into some of the varieties of starch, as the 
vital actions of the plant become more vigorous. Its composition, in its different 
varieties, as given by most analysts, C12 Hu Ou, or Cio Hio Oro, or even Cy His Ox, 
denotes that if it be formed from the starch, C12 Hio O10, it must be either by the 
addition of the elements of water, or by the abstraction of carbon ; and as its for- 
mation, during the germination of seeds, is attended with evolution of carbonic 
acid, it seems most probable that, in that case at least, it is formed in this last 
way, under the influence of the oxygen of the air. It appears again in the nec- 
taries of flowers, and in the ripening of fruits, as one of the latest results of the 
vital action of plants, in those parts of them which are fully exposed to air and 
light, but at a time when we may reasonably suppose that the vital affinities are 
becoming comparatively ineffective, and when carbonic acid is again evolved. It 
may be formed by the chemist from some of the varieties of starch by a kind of 
fermentation, excited by diastase, as in malting; or by a catalytic action of 
sulphuric acid; and it is formed from starch merely by the agency of cold, as 
in frozen potatoes, and from inuline merely by continued boiling in water; so 
that its formation from starch in vegetables seems to be most probably a simple 
chemical change, not the effect of a vital affinity. Farther, it is a compound 
which takes the crystalline form, essentially different from any form assumed 
by those parts of organized structures which exhibit truly vital phenomena, 
and retains its properties when exposed to air and water better than any of the 
matters of which organized forms are composed. [rom all these facts it may, 
be inferred, with great probability, that sugar, as it appears in the living vege- 
table, is generally to be regarded as a first product of decomposition of starch, by 
the agency of water and of the oxygen of the air, which appears to be the 
great agent in the resolution of those compounds, which the vital affinities have 
built up. 
6. On the other hand, the relation of starch and cellulose to the lignin, 
which forms the greater part of the solid matters of dicotyledonous plants seems 
to be nearly the reverse of their relation to sugar. This matter is always found 
incrusting, or incorporated with, the cells of vegetable textures; it gives them 
their solidity and strength, which all decompositions by chemical agents impair ; 
it cannot be formed from the compounds of starch by artificial means, but is 
formed from them in greatest quantity when the vital actions of plants are 
strongest ; and its composition is always stated as differing from the amylaceous 
compounds by containing more carbon; and less oxygen, in proportion to the 
hydrogen, than exists in the composition of water; its formula being stated as 
Caso Hy3 Oys. This, therefore, would appear to be clearly the result of truly vital 
affinities, continuing to actuate the elements of starch, after the formation of the 

