n of sodium carbonate, and add 5 drops of liquor
pancreaticus, or a few grains of Fairchild's extract of pancreas, in
each. Boil _B_, and make _C_ acid with dilute hydrochloric acid. Place
in each tube an equal amount of well-washed fibrin, plug the tubes with
absorbent cotton, and place all in a water-bath at about 100 degrees F.

Experiment 73. Examine from time to time the three test tubes in the
preceding experiment. At the end of one, two, or three hours, there is
no change in _B_ and _C_, while in _A_ the fibrin is gradually being
eroded, and finally disappears; but it does not swell up, and the
solution at the same time becomes slightly turbid. After three hours,
still no change is observable in _B_ and _C_.

Experiment 74. Filter _A_, and carefully neutralize the filtrate with
very dilute hydrochloric or acetic acid, equal to a precipitate of
alkali-albumen. Filter off the precipitate, and on testing the filtrate,
peptones are found. The intermediate bodies, the albumoses, are not
nearly so readily obtained from pancreatic as from gastric digests.

Experiment 75. Filter _B_ and _C_, and carefully neutralize the
filtrates. They give no precipitate. No peptones are found.

Experiment 76. _To show the action of pancreatic juice upon the
albuminous ingredients (casein) of milk_. Into a four-ounce bottle put
two tablespoonfuls of cold water; add one grain of Fairchild's extract
of pancreas, and as much baking soda as can be taken up on the point of
a penknife. Shake well, and add four tablespoonfuls of cold, fresh milk.
Shake again.

Now set the bottle into a basin of hot water (as hot as one can bear the
hand in), and let it stand for about forty-five minutes. While the milk
is digesting, take a small quantity of milk in a goblet, and stir in ten
drops or more of vinegar. A thick curd of casein will be seen.

Upon applying the same test to the digested milk, no curd will be made.
This is because the pancreatic ferment (trypsin) has digested the casein
into "peptone," which does not curdle. This digested milk is therefore
called "peptonized milk."

Experiment 77. _To show the action of bile_. Obtain from the butcher
some ox bile. Note its bitter taste, peculiar odor, and greenish color.
It is alkaline or neutral to litmus paper. Pour it from one vessel to
another, and note that strings of mucin (from the lining membrane of the
gall bladder)