194 ANTHROPOLOGY. 
gus, and extending towards the duodenum. The second layer consists of 
fibres running circularly in nearly parallel rings, beginning at the left. 
extremity. The third set of fibres take a very irregular or oblique direction, 
and appear as a continuation of the circular fibres of the cesophagus. The 
iniernal or mucous coat, also called villous, from its velvety appearance, is 
continuous with that lining, the cesophagus, and duodenum. When fresh 
and healthy, it is of a rosy or pinkish color. It is always thrown into folds or 
wrinkles, some of which are nearly parallel to the long axis of the stomach, 
and thus permit the distension of this organ; other folds intersect these, so 
as to cause an areolated appearance. At the cardiac orifice this membrane 
is folded longitudinally, and somewhat festooned. Corresponding to the 
pylorus is a circular fold, with a small aperture in the centre, the pylorie 
valve, encircled by a strong band of sphincter fibres; during life, when the 
sphincter acts, it can effectually separate the stomach from the intestine. 
When the stomach and duodenum are inflated and dried, the valve will be 
seen to present an appearance not unlike that of the iris. On carefully 
cleaning the inside of the stomach from all mucus, it will exhibit numerous 
projecting papille, and between them small pits or depressions, studded with 
minute holes. These pits are more or less circular, and most distinct 
towards the pyloric orifice; they secrete the gastric juice, the mucus being 
probably furnished by the papillee. 
The stomach is freely supplied with blood from the cceliac axis; the 
coronary and epiploic arteries, with the vasa brevia, inclose it in a network 
of inosculation. The numerous large veins enter into the portal system. 
The eighth nerves expand on its surface, and form a plexus round the car- 
diac orifice. Numerous nerves also are derived from the solar plexus of the 
sympathetic. 
The mucous coat of the stomach secretes the peculiar anti-putrescent and 
powerfully solvent liquid known as the gastric juice. By its action, aided 
by the temperature of the body and the motion of the stomach, food intro- 
duced through the cesophagus is, after a time, converted into a grey pulpy 
mass termed chyme. It is probable that the saliva (mixed with which the 
food comes to the stomach) performs an important part in the operation of 
digestion. 
2. THE DUODENUM is the next portion of the alimentary canal. It is so 
named from its length (from eight to nine inches), being about equal to the 
breadth of twelve fingers. This is the first and shortest, but most dilatable 
division of the small intestine ; it extends from the pylorus to the root of the 
mesentery, where the jejunum commences. The superior transverse portion 
ascends from the pylorus backwards and to the right, where it makes a sud- 
den or acute turn, and the middle or perpendicular portion then descends in 
front of the right kidney as low as the third lumbar vertebra; here it makes 
a second turn, from which the inferior transverse portion extends obliquely 
across the spine. The biliary and pancreatic ducts perforate the inner side 
of the perpendicular division of the duodenum. These pass through its 
coats very obliquely, and open into the intestine, sometimes separately, 
sometimes together, on a small papilla opposite the inferior angle. In the 
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