82 Alimentary Canal. 



TEETH. 



Sections of hard teeth are prepared in the same way 

 as bone. Teeth may be decalcified by the same pro- 

 cess as that used for bone, page 71. Good sections of 

 teeth in situ may be made by removing the lower jaw of 

 some small animal as rat or mole and decalcifying it, 

 after the lime salts have been thoroughly washed out, 

 it should be soaked in gum for 24 hours and then cut 

 with the freezing microtome. 



Sections may either be mounted without staining in 

 Canada balsam or they may be double stained with 

 picro-carmine and logwood. 



ALIMENTAKY CANAL. 



STOMACH. 



The stomach may be prepared in several different 

 ways. 



1st Method. Eemove and open a fresh stomach of 

 dog, cat or rabbit, and wash it slightly in dilute chromic 

 acid, then place it in the ordinary chromic acid mixture 

 and proceed as described at page 11. 



2nd Method. To show the peptic cells take fresh 

 stomach and wash quickly, then plunge into pure me- 

 thylated spirit. 



3rd Method. Put the stomach in Muller's fluid un- 

 washed, for 48 hours. Then cut narrow strips of the 

 mucous membrane about half an inch long by one 

 eighth of an inch wide and wash these in one-tenth per 

 cent, osmic acid, then place them in half per cent. 



