XIII. 

 DIGESTION. 



The Effect of the Digestive Fluids on Foods. 

 A. The Saliva. 



I. THE MICROSCOPICAL EXAMINATION OF SALIVA. 



Material. Saliva. 



Apparatus. A test-tube. A glass slide and cover-glass. A com- 

 pound microscope. 



Collect half a test-tube of saliva. Mount a drop on the 

 glass slide and examine with the compound microscope. 



Notice : 



a. The epithelial cells. Where did they come from? 



b. Possibly, debris of food. 



c. Forms of bacteria. 



II. THE EFFECT OF SALIVA, ON STARCH. 



Materials. Potato starch. Saliva. 



Apparatus. Warm water-bath, or one made of a large beaker. 

 A Bunsen burner. A ring-stand. A piece of wire gauze six inches 

 square. A thermometer. Test-tubes and rack. 



Prepare a warm water-bath by rilling the beaker to a 

 depth of three or four inches with water, and placing it 

 on the wire gauze on the ring-stand, over the Bunsen 

 burner. Stand the thermometer in the water and keep 

 it at a temperature of 42 C. 



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