body, and are evolved in the form of water, carbonic acid
and ammonia. The other portion of the food which furnishes
the material for excrements, must, therefore, necessarily con-
tain less of organic matter, and as the whole amount of
the inorganic constituents remain undivided with it, relative-
ly more of mineral matter than the original food from which
it is derived. An examination into the ultimate composition of
both, as found by direct analysis, proves the correctness of
this conclusion beyond doubt, and discloses, besides, a fact
which at once appears interesting and important in its rela-
tion to the efficiency of stable manure as a fertilizer. It is
the fact, that the excrements of animals contain relatively
more of nitrogen than the food from which they are derived,
or in other words, the processes of life transform the food
when passing through the animal body into a series of com-
pounds which contain the nitrogen in a form the more con-
centrated, the more they approach their ultimate destination
and final composition. We have seen before, that a portion
of the organic part of the food which evolves in the form of
water, carbonic acid and ammonia, is all that is subtracted
from it whilst under the influence of the vital powers; here
we find that, in consequence of this very process, the remain-
ing part, that which furnishes the material for excrements,
has increased its quantity of nitrogen far above the prop or
tion in which it originally constituted the food. "What is the
cause, we ask, of so close a connection of two facts, apparently
contradicting each other ? It admits of but one explanation,
as it indisputably proves that the relative quantities of water,
carbonic acid and ammonia, as they are evolved from the
lungs and through the skin of the animal, do in no way cor-
respond with the proportion in which their ultimate constit-
uents, carbon, hydrogen, oxygen and nitrogen, have origi-
nally formed the component parts of the food; there is, in
the form of carbonic acid and water, more carbon, hydrogen
and oxygen evolved, and consequently, in the form of am-
monia, less of nitrogen than it would be the case if the dif-
ferent constituents of food had equally participated in the
production of these substances.

In recapitulation of the different processes above alluded
to, to which the animal food is subjected whilst under the
influence of the vital powers, we may accordingly collect the
following conclusions relative to the composition of the excre-
ments if compared with the composition of the food from
which they were derived:

1. The absolute quantity of the excrements derived from a
certain quantity of food, amounts to not more than about
three-fifths by weight of the latter.

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