The action of each of these organs, the performance of each of these
various duties, involve in their operation a continual absorption of the
matters necessary for their support, from the blood, and a constant
formation of waste products, which are returned to the blood, and
conveyed by it to the lungs and the kidneys, which are organs that have
allotted to them the office of extracting, separating, and getting rid
of these waste products; and thus the general nourishment, labour, and
repair of the whole machine is kept up with order and regularity. But
not only is it a machine which feeds and appropriates to its own support
the nourishment necessary to its existence--it is an engine for
locomotive purposes. The Horse desires to go from one place to another;
and to enable it to do this, it has those strong contractile bundles of
muscles attached to the bones of its limbs, which are put in motion by
means of a sort of telegraphic apparatus formed by the brain and the
great spinal cord running through the spine or backbone; and to this
spinal cord are attached a number of fibres termed nerves, which proceed
to all parts of the structure. By means of these the eyes, nose, tongue,
and skin--all the organs of perception--transmit impressions or
sensations to the brain, which acts as a sort of great central
telegraph-office, receiving impressions and sending messages to all
parts of the body, and putting in motion the muscles necessary to
accomplish any movement that may be desired. So that you have here an
extremely complex and beautifully-proportioned machine, with all its
parts working harmoniously together towards one common object--the
preservation of the life of the animal.

Now, note this: the Horse makes up its waste by feeding, and its food is
grass or oats, or perhaps other vegetable products; therefore, in the
long run, the source of all this complex machinery lies in the vegetable