274 DIGESTION, CIRCULATION, AND ABSORPTION 



artificial pancreatic juice. Keep it in a warm bath at about blood heat for 

 a few hours. Then test with Fehling's solution. 



Observation. What is the result when the mixture is tested with 

 Fehling's solution ? 



Conclusion. What is the action of pancreatic juice on starch ? 



Method b. Shake a little melted butter or olive oil in a test tube half 

 full of artificial pancreatic juice. Note. Shake some oil and water in a 

 test tube. Add a few drops of ammonia, and shake vigorously again. 

 The resulting milky colored mixture is called an emulsion. Where have 

 you heard of it before ? 



Observations. 1. What is the appearance of the mixture ? Note. 

 The oil is now in small microscopic drops scattered throughout the water. 



2. What is the result of shaking the-oil or butter with pancreatic juice ? 



Conclusion. What is one result of the action of pancreatic juice 

 on oils and fats ? 



Method c. Add some blue litmus solution to \ test tube of milk. Add 

 some pancreatic juice and let the mixture stand in a warm bath at blood 

 heat for a few hours. " ' *" 



Observation. What is the final color of the mixture ? 



Conclusion. What has evidently been formed ? Note. The fats and 

 oils are finally split into glycerin and fatty acids and absorbed in this 

 form. 



Method d. Add some proteid (minced white of egg) to a test tube half 

 full of artificial pancreatic juice. Keep at blood heat for a few hours. 

 Shake occasionally. Test for peptones as under study of gastric juice. 



Observation. What is the appearance of the contents of the tube ? 



Conclusions. 1. Is the egg digested ? Has any other digestive juice 

 acted in the same way ? 



2. Write a summary of your conclusions regarding the effect of pan- 

 creatic juice on nutrients. 



2. ACTION OF BILE (OPTIONAL) 



Materials. Ox gall or bile, olive oil, white of egg, pancreatic juice, 

 test tubes. 



Observations. 1. Add some bile to minced white of egg in a test 

 tube. Also to some starch. Results when kept in warm bath for a few 

 hours ? 



2. Add pancreatic juice to minced white of egg in two tubes. Add 

 bile to one of the tubes. In which does digestion take place more quickly ? 



3. Put proteid in two test tubes. Add bile to one. Let stand in 

 warm place until putrefaction occurs. 



