Year: 1859

The nanie, humus, has been given to tho
black carbonaccous matter which results from
the putrefaction of organic substances. veg
etable humus is nothing but the woody matter
which burns slowly under the influence OF the
atmosphere and changes Into carbonic acid.
1t was believed for a long time that it was al
once absorbed by the root of the plants and
that its carbon, assimilated immediately, and
without transformation, contributed powerful
lv TO the nutrition of vegetables but it has
been proven that humus is insoluable in water
and that it nourishcs plants by presenting to
their roots slow and continuous source of
carbonic acid, which, dissoving in water, PEN
etrates to the interior of the plant. The de-
composition of humus is favored by the pres
ence of alkalies, which provoke the formation
of earbonic acid and form with it soluable car
Donates absorbed by the roots. 1t is necessa-
ry that the soil should be stirred so that 1t be-
come permeablc to the air, and that there be
formed in the humid earth an atmosphere of
carbonic acid which shall furnish to the young
plant its most important aliment. A plant can
vcgetate without humus; but that which ac-
CELEBRATES the development of the plant and
gains time, is of the highest importance to
the agriculturist.


1t is demonstrated that the alkalies
which we find in plants are necessary to vcge-
tation. At first they form with the carbonic
acid souabc carbonates which penetrate by
the roots into the vegetables, and afterwards,





acid are decomposed; form, by means of OK
ygen, with which they combine, oxalic and
tartarie acid, and then become sugar, starch or
woody fibre; and in proportion as the acids
are transformed the alkalies diminish in the
sap. This can be observed in the ripening of
fruit.


Thus vegetable acids are Indispensable to
tho existence of plants, and their formation
depends 1st water and carbonic acid, which
combine to form them, and End on alkalieS,
which provoke this combination. These veg
etable acids being always found combined with
alkalies, the necessity of tho latter is incou-
tcstablc. Besides, if the life of plants is con-
nected with their presence, their proportion
should invariably be as that of the acids to
which they serve as bases. AS all the aka


line bases in their mode of acting can be mu-
tually substituted, it suffces that wanting
base be replaced by an equivalent of another
base. Thus, they have analized the ashes of
two pines of the same species, collected from
different localities; these ashes showing faith
fully the total of fixed alkaline bases contain
ed in the wood One of the pines contained
magnesia, which was wanting in the other;
the quantities of potash and lime contained in
them were also very unequal, but notwithstan-
ding this difference of composition the ashes
of the two pines contained like number of
equivalents of alkaline bases-that is to say,
that the quantity of oxygen all the bases took
together, was the same in each tree.


Ihe chemist LeIblS drew from these facts
very important conclusions it is, that if def
mite and constant quantities of vegetable salts
are to be found under certain conditions in the
organs of the plants and that these salts are
indispensable to the accomplishment of their
functions, the plants should always have to
absorb potash or lime for instance, and If they
could not find enough of it, the quantity want
ing should be replaced by q corresponding
proportion of another alkaline base-if none
of these bases are presented TO the plants they
cannot develop, and die. And that which sue
ceeds in proving that the presence of certain
alkaline bases which are found in the ashes OF
plants, far from being accidental, are essential
to their existence. is this, that If aplant is
forced to absorb salt which is not suitable to
it, and which is brought to it by the water
which surrounds its roots, it afterwards re-
turns it to the earth.