36 LABORATORY EXERCISES. 



. mucous membrane from the cardiac (cesoph- 

 ageal) end of the stomach. Dry the mem- 

 brane between folds of blotting-paper, and 

 mince it finely. Place in a bottle and add 5 

 times its bulk of strong glycerin. Set aside 

 for several days, stirring occasionally. Filter 

 through muslin. (The glycerin dissolves the 

 pepsin.) The glycerin extract may be kept 

 almost indefinitely. 



When required for use* in digesting nitro- 

 genous substances, add 10 times its volume of 

 .2% hydrochloric acid, and filter. 



Instead of preparing the glycerin extract an 

 artificial gastric juice may be made by dissolv- 

 ing solid pepsin in water and adding the hydro- 

 chloric acid. 



B. Preparation of pancreatin solution. 



Leave the pancreas of a pig moistened with 

 water for a day ; then mince it well and add i o 

 times its volume of strong glycerin. Set the 

 mixture aside for several days, stirring occa- 

 sionally. Filter through muslin. (The gly- 

 cerin dissolves out the pancreatin.) 



The glycerin extract acts on starch and nitro- 

 genous substances. When required to digest 

 fats add 10 volumes of 1.5$ solution of sodium 

 carbonate, shake and filter. 



An artificial pancreatic juice can be made 

 by dissolving solid pancreatin in water and 

 adding the sodium carbonate solution. 



C. Preparation of bile. 



Procure the fresh gall-bladder of an ox : wash 



