J10 LABORATORY MANUAL 



In the third, place a few small bits of egg-white and 

 cover with saliva. Label No. 3. 



In the fourth, place a few c.c. of olive oil and saliva. 

 Label No. 4. 



Shake the tubes and set them in a basin of water 

 having a temperature of 36 C., or about body tem- 

 perature. Leave them for half an hour and then test 

 the contents of the tubes. 



Tube No. 1 Test part of the contents for starch 

 and the remainder for sugar. 



Tube No. 2 Repeat the test applied to tube No. 1. 



Tube No. 3 Has the egg-white begun to dissolve? 



Tube No. 4 Has any change taken place in the oil? 



Upon which of the foodstuffs does saliva act? 



Does it act in an acid or base solution? 



Exercise 74. Digestion in the Stomach. 

 Object: To determine the foodstuffs acted upon in 

 the stomach. 



Apparatus 



Corn starch Test tube clamp 



Egg-white Iodine 



Olive oil Sodium hydroxide (dilute) 



Milk Pepsin 



Hydrochloric acid (dilute) Rennet 



Fehling's solution Bunsen burner 



Test tubes and racks 



Directions: In the stomach the food comes in con- 

 tact with the gastric juice. This contains two active 

 substances, pepsin and rennin. 



