174 SPECIAL PHYSIOLOGY 



(c) To 5 c.c. of cotton-seed oil containing a little free fatty acid 

 add ten drops of strong sodium carbonate solution and shake. A 

 good stable emulsion is made in this way. 



In what way is this emulsion different from those which precede? 

 Which one of the emulsions given above is most like the emulsions 

 formed in the small intestine? 



(d) What materials present in the small intestine tend to promote 

 emulsification of fats? 



(6) The Diffusibility of Fats or Their Derivatives or Modifications. 

 Fill five dialyzers as follows: 

 (a) Milk. 

 (6) Solution of soap. 



(c) 10 per cent, glycerin. 



(d) Emulsion (5, a). 



(e) Emulsion (5,c). 



Complete the observations on the following day, determining what 

 derivations or modifications of fat or oil are diffusible. How may 

 the presence of soap in the diffusate be determined? 



IX. INTESTINAL DIGESTION. 



1. Materials. Two pig pancreases; 200 c.c. of pig or ox bile. 



2. Preparation. (1) Aqueous Pancreatic Extract, (a) Free a pig 

 pancreas of fat. 



(6) Grind it in a meat hasher. 



(c) Extract with water kept at a temperature of 25 to 28 C. 



(d) After two hours strain through linen and filter through absorb- 

 ent cotton. 



(2) Glycerin Extract of the Pancreatic Ferments, (a) After freeing 

 the gland of fat grind it. 



(6) Place it in two volumes of absolute alcohol for two days. 



(c) Drain off the alcohol and transfer to two volumes of pure 

 glycerin. 



(d) After one week press out the glycerin, which has extracted the 

 ferments. 



This glycerin extract will keep indefinitely. To make artificial 

 pancreatic juice proceed as follows: 



(e) To one volume of the glycerin extract add five or six volumes 

 of water and sufficient sodium carbonate solution to give the mixture 

 a distinctly alkaline reaction. 



(3) Preliminary Experiments on Bile. This secretion may easily be 

 procured from the slaughter-house at almost any time of the year. 



(a) To diluted bile add dilute acetic acid. The copious yellow 

 precipitate is mucin. 



(6) To diluted bile add absolute alcohol; mucin is precipitated; 



