PANCREATIC DIGESTION. 59 



add about 5 c.c. of Millon's reagent to the test-tube and 

 heat. Why is this result positive? 



(c) Piria's Test. Place a few of the tyrosine crystals upon 

 a small watch-glass with two drops of concentrated H 2 S0 4 and 

 warm for half an hour on the water-bath. Then transfer it 

 with about 15 c.c. water to a test-tube and neutralize with 

 BaC0 3 in substance. Filter and add a few drops of weak 

 ferric chloride solution (neutral). A positive test is evidenced 

 by the formation of a violet .color. 



(d) Morner's Test. To a little of the powder placed in a 

 test-tube add a few c.c. of Morner's reagent, and heat care- 

 fully to boiling. A green color develops which is quite 

 lasting. 



CH JX / NH * 



LEUCINE, >CH-CH,-CH 



PTT / \ /}J 



X)H 



Make use of the substance obtained from the pancreatic 

 digestion. 



(a) Examine some crystals under the microscope. 



(6) Place a little in a clean dry test-tube and warm care- 

 fully. The leucine sublimes, without melting, on the cold 

 parts of the tube. If the powder is heated too high or 

 suddenly, the substance is decomposed and the odor of 

 amylamine is given off. Write the equation for the formation 

 of this substance. 



(c) Scherer's Test. Heat a little leucine with two drops of 

 concentrated HN0 3 upon a platinum foil over a free flame 

 until a colorless residue is obtained. Then add two drops 

 of NaOH and evaporate carefully in the flame. The mass 

 becomes dark red in color and rolls around on the foil like 

 an oil-drop. 



