type of organized life made in the very image of God.

The muscles, then, subserve an endless variety of purposes. By their aid
the farmer employs his implements of husbandry, the mechanic deftly
wields his tools, the artist plies his brush, while the fervid orator
gives utterance to thoughts glowing with heavenly emotions. It is by
their agency that the sublimest spiritual conceptions can be brought to
the sphere of the senses, and the noblest, loftiest aims of to-day can
be made glorious realizations of the future.

* * * * *

CHAPTER IV.

PHYSIOLOGICAL ANATOMY.

THE DIGESTIVE ORGANS.

_Digestion_ signifies the act of separating or distributing, hence its
application to the process by which food is made available for nutritive
purposes. The organs of digestion are the Mouth, Teeth, Tongue, Salivary
Glands, Pharynx, Esophagus, the Stomach and the Intestines, with their
glands, the Liver, Pancreas, Lacteals, and the Thoracic Duct.

[Illustration: Fig. 26.
A view of the lower jaw. _1_. The body.
_2, 2_. Rami, or branches. _3, 3_. Processes of
the lower jaw. _m_. Molar teeth. _b_. Bicuspids,
_c_. Cuspids. _i_. Incisors.]

The _Mouth_ is an irregular cavity, situated between the upper and the
lower jaw, and contains the organs of mastication. It is bounded by the
lips in front, by the cheeks at the sides, by the roof of the mouth and
teeth of the upper jaw above, and behind and beneath by the teeth of the
lower jaw, soft parts, and palate. The soft palate is a sort of pendulum
attached only at one of its extremities, while the other involuntarily
opens and closes the passage from the mouth to the pharynx. The interior
of the mouth, as well as other portions of the alimentary canal, is
lined with a delicate tissue, called _mucous membrane_.

The _Teeth_ are firmly inserted in the alveoli or sockets, of the upper
and the lower jaw. The first set, twenty in number, are temporary, and
appear during infancy. They are replaced by permanent teeth, of which
there are sixteen in each jaw; four incisors, or front teeth, four
cuspids, or eye teeth, four bicuspids, or grinders, and four molars, or
large grinders. Each tooth is divided into the crown, body, and root.
The _crown_ is the grinding surface; the _body_, the part projecting
from the jaw, is the seat of sensation and nutrition; the _root_ is that
portion of the tooth which is inserted in the alveolus. The teeth are
composed