ime, the contents of the stomach is reduced to
a rather uniform and pulpy mass which is called _chyme_. Portions of this
are now passed at intervals into the small intestine.

*Muscular Action of the Stomach.*--The muscles in the walls of the stomach
have for one of their functions the mixing of the food with the gastric
juice. By _alternately_ contracting and relaxing, the different layers of
muscle keep the form of the stomach changing--a result which agitates and
mixes its contents. This action varies in different parts of the organ,
being slight or entirely absent at the cardiac end, but quite marked at
the pyloric end.

Another purpose of the muscular coat is to empty the stomach into the
small intestine. During the greater part of the digestive period the
muscular band at the pyloric orifice is contracted. At intervals, however,
this band relaxes, permitting a part of the contents of the stomach to be
forced into the small intestine. After the discharge the pyloric muscle
again contracts, and so remains until the time arrives for another
discharge.

In addition to emptying the stomach into the small intestine, these
muscles also aid in emptying the organ upward and through the esophagus
and mouth, should occasion require. Vomiting in case of poisoning, or if
the food for some reason fails to digest, is a necessary though unpleasant
operation. It is accomplished by the contraction of all the muscles of the
stomach, together with the contraction of the walls of the abdomen. During
these contractions the pyloric valve is closed, and the muscles of the
esophagus and pharynx are in a relaxed condition.(59)

[Fig. 70]

Fig. 70--*Passage from stomach* into small intestine. Illustration also
shows arrangement of mucous membrane in the two organs. _D._ Bile duct.

*The Small Intestine.*--This division of the alimentary canal consists of a
coiled tube, about twenty-two feet in length, which occupies the central,
lower portion of the abdominal cavity (Fig. 71). At its upper extremity it
connects with the pyloric end of the stomach (Fig. 70), and at its lower
end it joins the large intestine. It averages a little over an inch in
diameter, and gradually diminishes in size from the stomach to the large
intestine. The first eight or ten inches form a short curve, known as the
_duodenum_. The upper two fifths of the remainder is called the _jejunum_,
and the lower three fifths is known