412 
DIGESTIVE ORGANS AND FOOD 
fats into oils, but many of the fats used as food remain solid 
at body temperature and are unchanged in the stomach. 
After one or two hours the food passes into the intestine 
and undergoes further changes in another alkaline medium. 
Here the pancreatic juice, which is made in 
the pancreas, comes into contact with the 
digested and partly digested food, causing 
three different changes. One is to complete 
the change of proteins into simpler products; 
a second is to finish converting starches into 
sugar; while the third is to assist the bile 
(the digestive juice made in the liver) to 
digest the fats. The digestion of the food 
is practically completed in these three re¬ 
gions of the digestive tube, although diges¬ 
tion continues to some extent after the food 
is passed into the large intestine. 
The pepsin in the gastric juice is called an 
enzyme (en'zlm : Greek enzymos, fermented) 
or ferment. There are three different en- 
of the inner wall of zymes in the pancreatic juice (trypsin, 
the stomach pro- amylopsin, and steapsin), none in the bile, 
ject into the tissiies anc j one j n ^ sa p va These enzymes are 
of the stomach as . . J 
minute pockets, the chemical bodies which digest food. All 
The cells shaded plants and animals digest their food by 
in this drawing are meang of enzymes . 
the ones that are ~ 
at the end of the Inorganic foods, such as water, oxygen, 
pocket and are the and salts, man takes into his body, making 
tKegastric jutee*' 6 them , part of his living P roto P la sm, or using 
them in oxidation. There is a large amount 
of water in man, enough to make up nearly two thirds the 
total weight of his body. All of his food contains water. 
Oxygen is breathed in from the air, and the various salts, 
such as common salt, sodium chloride (so'di-um klo'rid, or 
rid), calcium (kal'si-um), magnesium (mag-ne'zhi-um, or 
man Gastric 
Gland. 
The linine cells 
