it lives, the more difficult is the process of assimilation, and the
more complex the chain of digestive organs; for it must be evident to
all, that the same apparatus that converts _flesh_ into _flesh_, is
hardly calculated to transmute _grass_ into flesh. As the process of
digestion in carnivorous animals is extremely simple, these organs are
found to be remarkably short, seldom exceeding the length of the
animal's body; while, where digestion is more difficult, from the
unassimilating nature of the aliment, as in the ruminant order, the
alimentary canal, as is the case with the sheep, is _twenty-seven times
the length of the body._ The digestive organ in all ruminant animals
consists of _four stomachs_, or, rather, a capacious pouch, divided by
doorways and valves into four compartments, called, in their order of
position, the Paunch, the Reticulum, the Omasum, and the Abomasum. When
the sheep nibbles the grass, and is ignorantly supposed to be eating, he
is, in fact, only preparing the raw material of his meal, in reality
only mowing the pasture, which, as he collects, is swallowed instantly,
passing into the first receptacle, the _paunch_, where it is surrounded
by a quantity of warm saliva, in which the herbage undergoes a process
of maceration or softening, till the animal having filled this
compartment, the contents pass through a valve into the second or
smaller bag,--the _reticulum_, where, having again filled the paunch
with a reserve, the sheep lies down and commences that singular process
of chewing the cud, or, in other words, masticating the food he has
collected. By the operation of a certain set of muscles, a small
quantity of this softened food from the _reticulum_, or second bag, is
passed into the mouth, which it now becomes the pleasure of the sheep to
grind under his molar teeth into a soft smooth pulp, the operation being
further assisted by a flow of saliva, answering the double purpose of
increasing the flavour of the aliment and promoting the solvency of the
mass. Having completely comminuted and blended this mouthful, it is
swallowed a second time; but instead of returning to the paunch or
reticulum, it passes through another valve into a side cavity,--the
_omasum_, where, after a maceration in more saliva for some hours, it
glides by the same contrivance into the fourth pouch,--the _abomasum_,
an apartment in all respects analogous to the ordinary stomach of
animals, and where the process of digestion, begun and carried on in the
previous three, is here consummated, and the nutrient principle, by
means of the bile, eliminated from the digested aliment. Such is the
process of digestion in sheep and oxen.