1. Materials. - Glycerin Extract Of The Pancreatic Ferments

One hundred cubic centimeters of ox bile. Starch, fibrin, olive oil, milk, and bread.

2. Preparation

To make artificial pancreatic juice take one volume of the glycerin extract, add 5 or 6 volumes of water and sufficient sodium carbonate to give the mixture a distinctly alkaline reaction.

3. Experiments And Observations

(1) To starch paste add artificial pancreatic juice; keep the mixture warm. After a short time test a portion of the mixture with iodin and another portion with Fehling's solution, noting results.

(2) Test the action of artificial pancreatic juice on fibrin. If no influence is noted we will understand it is because trypsin of the pancreatic juice lacks the activating agent furnished by the succus entericus - namely, the enterokinase.

(3) Mix a few cubic centimeters of neutral olive oil with an equal volume of the artificial pancreatic juice. Shake the mixture vigorously. No permanent emulsion is formed. Place one half of the mixture in the incubator or a jar of warm water. After an hour examine again, shaking vigorously. This time the oil will be readily emulsified. The explanation of this is that during the hour the lipase of the pancreatic juice had changed some of the fat into fatty acids and glycerin. The former readily enters into chemical combinations with the weak alkali, forming soaps. These in turn emulsify the unchanged fats, as was shown in a preceding section.

(4) To the second part of the mixture add an equal volume of bile; shake the mixture vigorously. A good emulsion is formed. How is this emulsion formed? What factor does the bile add? What is the relation of Experiment 4 to Experiment 3? Pancreatic juice contains a fat-splitting ferment whose action liberates fatty acids.

(5) To Test The Action Of Bile On Foods

(a) To starch paste add several volumes of dilute bile; shake thoroughly and note results. Is the starch digested? (b) To fibrin add bile. Is it digested? (c) To oil which contains free fatty acids add bile; shake the mixture vigorously. Is it emulsified? (d) To neutral oil add bile; shake the mixture vigorously. What is the result?