hile this is believed by some to be an actual process of
digestion, the advocates of the solution theory claim that it is a process
accompanying and aiding the conversion of fat into fatty acid and
glycerine.(63)

*The Intestinal Juice* is a clear liquid with an alkaline reaction,
containing water, mineral salts, and certain proteid substances that may
act as enzymes. It assists in bringing about an alkaline condition in the
small intestine and aids in the reduction of cane sugar and maltose to the
simple sugars, dextrose and levulose. Since it is difficult to obtain this
liquid in sufficient quantities for experimenting, its uses have not been
fully determined. Recent investigators, however, assign to it an important
place in the work of digestion.

*Work of the Small Intestine.*--The small intestine is the most important
division of the alimentary canal. It serves as a receptacle for holding
the food while it is being acted upon; it secretes the intestinal juice
and mixes the food with the digestive fluids; it propels the food toward
the large intestine; and, in addition to all this, serves as an organ of
absorption.

Digestion is practically finished in the small intestine, and a large
portion of the reduced food is here absorbed. There is always present,
however, a variable amount of material that is not digested. This,
together with a considerable volume of liquid, is passed into

*The Large Intestine.*--The large intestine is a tube from five to six feet
in length and averaging about one and one half inches in diameter. It
begins at the lower right side of the abdominal cavity, forms a coil which
almost completely surrounds the coil of small intestine, and finally
terminates at the surface of the body (Figs. 2, 71 and 73). It has three
divisions, known as the caecum, the colon, and the rectum.

[Fig. 73]

Fig. 73--*Passage from small into large intestine.* At the ileo-caecal valve
is the narrowest constriction of the food canal.

_The caecum_ is the pouch-like dilatation of the large intestine which
receives the lower end of the small intestine. It measures about two and
one half inches in diameter and has extending from one side a short,
slender, and blind tube, called the _vermiform appendix_. This structure
serves no purpose in digestion, but appears to be the rudiment of an organ
which may have served a purpose at some remote period in the history of
the