student will compare Sections 10 and 11, he will notice that in
those paragraphs no account is taken of the sulphur among the
katastases, the account does not balance, and he will at once see
that here probably is the missing item on the outgoing side. The bile,
through the presence of these salts, is strongly alkaline, and so
stops the action of the gastric juice, and prepares for that of the
pancreas, which can act only in an alkaline medium. The fermentive
action of the bile is trifling; it dissolves fats, to a certain extent, and
is antiseptic, that is, it prevents putrefaction to which the chyme
might be liable; it also seems to act as a natural purgative.

Section 27. The bile, as we shall see later, is by no means the sole
product of the liver.

Section 28. The pancreatic juice, the secretion of the pancreas is
remarkable as acting on all the food stuffs that have not already
become soluble. It emulsifies fats, that is, it breaks, the drops up
into extremely small globules, forming a milky fluid, and it
furthermore has a fermentive action upon them; it splits them up into
fatty acids, and the soluble body glycerine. The fatty acids combine
with alkaline substances (Section 26) to form bodies which belong to
the chemical group of Soaps, and which are soluble also. The
pancreatic juice also attacks any proteids that have escaped the
gastric juice, and converts them into peptones, and any residual
starch into sugar. Hence by this stage, in the duodenum, all the food
constituents noticed in Section 17 are changed into soluble forms.
There are probably, three distinct ferments in the pancreatic juice
acting respectively on starch, fat, and proteid, but they have not
been isolated, and the term pancreatin is sometimes used to
suggest the three together.

Section 29. A succus entericus, a saliva-like fluid secreted by
numerous small glands in the intestine wall (Brunner's glands,
Lieberkuhnian follicles), probably aids, to an unknown but
comparatively small extent, in the digestive processes.

Section 30. The walls of the whole of the small intestine are engaged
in the absorption of the soluble results of digestion. In the
duodenum, especially, small processes, the villi project into the
cavity, and being, like the small hairs of velvet pile, and as thickly
set, give its inner coat a velvety appearance. In a villus we find
(Figure IX., Sheet 3) a series of small blood-vessels and with it
another vessel call