CHANGES FOOD UNDERGOES IN THE 
digestive tract. 313 
T. he albumen is changed into alkali-albumen by the action 
o sodium carbonate. The change to alkali-albumen and pen- 
one as accomplished by trypsin is by gradually eroding the 
pioteid from the surface, thus diminishing it in size While 
the above changes are taking place, there are formed two 
mti ogeneous bodies : leucin, belonging to the fatty acids, and 
tyrosin, to the aromatic acid group. 
As pancreatic digestion proceeds, various unknown de¬ 
composition products appear, chief of which are indol and 
s atol, which cause the peculiar disagreeable odor of pan¬ 
creatic digestion. Small quantities of phenol are also pro- 
duced. 1 
Saponification is the splitting up of a portion of the fats 
into g ycerine and leucin by the action of a special ferment_ 
steapsin. 
Emulsification is the reduction of fat to a very fine state of 
subdivision, and facilitated by (i) the albumen in solution ; <2\ 
e alkilmity of the fluid ; (3) the presence of soap; and (4) 
the motion of the intestines. 
The amylolytic power of the pancreatic fluid is more rapid 
and energetic in its effect on starch than that of the saliva. It 
is said to affect raw as well as boiled starch, which is due to t 
special ferment-amylopsin. 
Recapitulation; The pancreatic fluid, (1) assists in neutral- 
izmg the acid gastric juice ; (2) emulsifies and saponifies fats ; 
13 ) converts proteids into peptones; (4) converts starch into 
grape sugar. 
While the above changes are taking place, the ingesta is 
urther acted upon by the secretion from the liver—bile. In 
he Protoplasm of the liver cells are several varieties of granules, 
he commonest being bright, refracting fat globules, which 
rary in amount with the different stages of digestion. Others, 
)f a yellow color, secrete the coloring matter of the bile. 
Others, less refracting and colorless, are supposed to produce 
py cogen. 
Bile is an alkaline, golden-yellow fluid, of bitter taste, 
specific gravity 1,018, and is composed of mucin, bile pig- 
nents, sodium salts of bile acids, cholesterin, lecithin, salts 
nd water. 
