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 Kttle lime add weak hydrochloric acid. 

 Observations. — What happens? 



Conclusion. — What might be the effect of gastric juice upon 

 certain salts taken into the body? 



Froblem 190: 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 Fehhng'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 emulaion 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 



