338 Association of American Geologists and Naturalists. 
Berzelius who first described and named geine, has utterly abandon- 
ed that name* as improper, there being no such proximate principle, it 
having been proved to be a very complex compound of new and pecu- 
liar acids. Those which we know at present are the following: crenic 
acid, apocrenic acid, humic acid, humin, extract of humus, glairin, glu- 
cic acid, apoglucie acid and coal of humus. 
The five first of these substances are generally present in fertile soils. 
Crenic acid forms two salts with lime, one of which, the crenate, is very 
soluble in water and in alcohol, while the subcrenate is more difficult- 
ly soluble. 
Apocrenic acid is highly charged with nitrogen, and is a very valu- 
able ingredient in soils, furnishing a portion of the nitrogenous matter 
of plants. It is probably formed by the gradual change of vegetable 
matters through the influence of the air and ammoniacal salts derived 
from decomposing animal manures and from rain. It forms from the 
crenates and humates, when they are exposed to atmospheric influence, 
by breaking up the soil during cultivation. Hence we see that a yellow 
soil turns black by two or three years’ exposure to the atmosphere, and 
from an unfertile state becomes fertile. We can readily produce the 
same result ina few hours, when we operate on a small quantity of 
soil in the laboratory. Apocrenic acid forms salts with lime and with 
peroxide of iron, which are nearly insoluble in water, but which are 
readily decomposed by the action of carbonate of ammonia, or by 
potash or soda; so that we may readily conceive of the fertilizing 
influence of these alkaline matters, since they render the organic ma- 
nures, which were before insoluble, perfectly soluble in water, so that 
they may be absorbed by the rootlets of plants. If these matters are 
absorbed, as they infallibly must be, it is evident that they must under- 
go a series of modifications in the sap vessels, so that they are no lon- 
ger found in the juices of plants in the state which they were when they 
were first absorbed. Now, by analysis of the sap of plants before the 
putting forth of their foliage, we find certain extractive matters and su- 
gar. In some, apoglucic and glucic acid have been discovered. 
Let us then consider the composition of these substances, and see 
whether it is possible for humic acid, for instance, to pass by chemical 
changes into sugar. 
: Carbon. Hydrogen. Oxygen. 
Sugar is composed of _ - - 6 10 5 
Glucic acid of ° - - 4.8 10 5 
Humic acid of : : - 40 24 12 
Ulmin from sugar - : - 40 32 14 
* The erroneous statement in the Amer. Jour. of Science, was owing to the re- 
viewer having only a spurious edition of Berzelius’ Chemistry, which was printed 
in French at Bruxelles. 
