Chylification--Not well known.--Organs concerned in it.--The intestinal canal--Its general structure.--Peritoneal coat--Mesentery--Muscular coat--Uses of these.--Air in intestines--Uses of.--Mucous coat--Analogous to skin--The seat of excretion and absorption--Mucous glands--Absorbent vessels--Course of chyle towards the heart.--Nerves of mucous coat.--Action of bowels explained.--Individual structure of intestines--The Duodenum--Jejunum--and Ileum.--Liver and pancreas concerned in chylification--Their situation and uses.--Bile, its origin and uses.--The pancreas--Its juice--The jejunum described--The ileum--Cœcum--Colon--and Rectum.--Peristaltic motion of bowels--Aids to it.--Digestion of vegetables begins in stomach but often finished in the bowels.--Illustration from the horse--Confirmation by Dupuytren. The conversion of food into chyme, an operation which, as we have seen, takes place in the stomach, is only one of the series of changes which aliment undergoes before becoming fit to be assimilated with the living body; and the next process which we have to notice is _chylification_, or that by which _chyme_ is converted into _chyle_. In proportion as chyme is formed from the food, it is gradually propelled, as already shewn, through the pyloric orifice of the stomach into the _duodenum_ or beginning of the small intestine. On its arrival there, it is acted upon by the _bile_ from the liver, and the _pancreatic juice_ from the pancreas; and the result is the separation of the chyme into two distinct substances,--the one a milky-white fluid called _chyle_, which is absorbed into the system, and forms nutriment,--and the other a yellowish and more consistent mass, which is the indigestible remains of the food, and which, after traversing the whole length of the intestinal canal, and being there mixed with the waste matter separated from the blood in order to be thrown out of the system through the same channel, is at last expelled in the form of _fæces_ or excrement.