PROBLEM 191 225 



a soluble protein (a peptone). Test Nos. 2, 3, 4, and 5 with biuret 

 test, noting results, and remembering that whenever there is 

 peptone present the mixture in the test tube shows a rose pink color. 

 Conclusion. 1. What conditions are necessary for the diges- 

 tion of protein? 



2. What is the effect of an extreme heat and cold on the action 

 of hydrochloric acid and pepsin with a protein ? 



3. Make a table to give all your results of the above tests of 

 conditions necessary for digestion of protein. 



Problem 189: To determine another effect of gastric juice. 

 Materials. Lime and hydrochloric acid. 

 Method. To a little lime add weak hydrochloric acid. 

 Observations. What happens? 



Conclusion. What might be the effect of gastric juice upon 

 certain salts taken into the body ? 



Problem WO: To note the action of pancreatic juice on 

 starch. 



Materials. Make some artificial pancreatic juice by mixing 5 

 grains of pancreatin and 10 grains of baking soda in 100 c.c. of 

 water, Fehling's solution. 



Method. Add some of this artificial pancreatic juice to some 

 dilute starch paste. Keep at about body temperature for a few 

 hours, then test with Fehling's solution. 



Observations. What occurred when Fehling's solution was 

 added? 



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



Problem 191: To note the effect of pancreatic juice on oils 

 and fats. 



Materials. Test tube, oils, baking soda. 



Method. Shake up oil and water. What happens? Then 

 add a little alkaline substance, e.g., baking soda. What hap- 

 pens? Now shake up water with artificial pancreatic juice. 

 What happens? 



NOTE. An emulsion is formed by breaking fats up into very small droplets 

 which float in a liquid, making a milky appearance. In addition to emulsifying 

 HUNTER LAB. PROB. 15 



