NUTRITION. 59 
food, except fat, and all the blood-forming portion of vegetable 
food. 
5. Chylification—Wnhen a certain quantity of chyme has been formed in 
the stomach, the valve which closes the pyloric! orifice (d, fig. 52), or open- 
ing between the stomach and the small intestine, is opened, and it passes 
out ; but no food is allowed to pass out that has not been properly mixed 
with and acted upon by the gastric juice. In the small intestine, the 
chyme is mixed with three new fluids—the bile,? the pancreatic? juice, and 
the intestinal juice. The bile is a greenish-yellow liquid, secreted by the 
liver, and kept stored in a little bag near it, called the gall-bladder, from 
which, as well as directly from the liver, it is discharged into the intestine, 
close to where the latter leaves the stomach, f, fig. 52. Its principal 
function is to digest the fatty part of the food, which the gastric juice 
does not act upon. The pancreatic juice is a fluid very like saliva, which 
is also poured into the intestine at the same place as the bile, g, fig. 52. 
One of its functions is to complete what was begun by the saliva—namely, 
to convert starchy matter into sugar. It also serves further to dilute the 
chyme, and performs a very important chemical process, too complex to 
be described here. The intestinal juice unites in itself the properties both 
of the saliva and of the gastric juice—namely, the power of converting 
starchy matter into sugar, and of dissolving all animal food but fat, and 
the blood-giving portion of vegetable food. 
In the intestine, then, we have seen that there is a provision for 
reducing nutritious matter of every kind to a state fit for absorption, 
the fluid here acting on the food being compounded of the saliva, 
the gastric, the pancreatic, the intestinal juices, and the bile. And as 
the process of thus reducing the food is being carried on whilst the 
food moves through the intestine, so the nutritious part is being with- 
drawn by absorption. One part, which is perfectly reduced, and fit for 
passing into the system at once, is taken up by the blood-vessels (in the 
stomach as well as in the intestine); another part, which seems to be 
blood ‘in an early stage of its formation, with a large excess of fatty 
matter, is called chyle [Greek chylos, juice], and is taken up by the 
lacteals,* a system of absorbent vessels, so called from the white, milk- 
like appearance of their contents. 
After the chyle has been taken up by the lacteals, there remain certain 
parts of the food which have been rejected as comparatively worthless for 
nutrition. This portion of the food, called the feces | Latin, ‘grounds’], 
passes from the smaller into the larger intestine, in which most of the 
1 From Greek pylouros, a porter, from pylé, a gate, and owr'os, a guardian. 
2 Latin bilis, connected with fel, fellis, the gall-bladder. 
3 From Latin pancreas, a fleshy gland under and behind the stomach, by which the fiuid is 
secreted, from Greek pan, all, and xreas, flesh. 4 From Latin lac, lactis, milk. 
>» 
