TO PREPARE DIGESTIVE JUICES. 35 



C. The tongue. 



1. What is the shape of the tongue? 



2. Where is the tongue attached? 



3. What parts of the walls of the mouth-cavity 



can be touched by the tip of the tongue ? 



4. What differences do you note between the 



upper and lower surfaces of the tongue? 



D. The use of the lips and tongue in speaking. 



1. Pronounce .the vowels of the alphabet. 



a. Are the lips closed or open? 



b. Does the tip of the tongue touch the 



teeth? 



c. Does the tip of the tongue touch the 



palate ? 



d. What is the shape of the mouth-cavity 



when you are pronouncing each of 

 these vowels? 



2. What consonants necessitate the closing of 



the lips? (These consonants are called 

 labials.) 



3. What consonants require the tongue to 



touch the teeth? (These are called the 

 lingual consonants.) 



18. TO PREPARE DIGESTIVE JUICES. (Dem.) 



Materials . Cardiac end of pig's stomach; pancreas of pig; gall of 

 ox ; strong gl \ r cerm, 1% solution of hydrochloric acid, 1 5% solution 

 of sodium carbonate: solid pepsin, pancreatin, and ox -gall. 



A. Preparation of pepsin solution. 



Procure the stomach of a pig, wash it out 

 with a gentle stream of water. Tear off the 



