158 FATS, OILS AND LIPINES. [cH. VI. 



165. Shake a few drops of olive oil with 5 cc. of ether in a 

 dry tube. The oil completely dissolves. Repeat the experiment 

 with alcohol instead of ether. The oil dissolves partially, but is not 

 so soluble in alcohol as in ether. Pour the alcoholic solution into 

 water. The fat is precipitated as an emulsion. 



166. Touch a piece of writing paper with a glass rod that has 

 been dipped in olive oil. The paper is rendered translucent. 



Preparation of pancreatic lipase. A perfectly fresh pig's pancreas is 

 freed from fat, weighed, finely minced and ground with sand. It is then 

 treated with three times its weight of water and its own weight of strong alcohol. 

 It is allowed to stand for three days at room temperature and strained through 

 muslin. It must not be filtered. When not in use it should be kept in a 

 refrigerator. It will remain active for a considerable time. 



NOTE. Pancreatic lipase is a ferment that only acts with the co-operation 

 of a co-ferment, which is soluble in water and not destroyed by boiling. Bile 

 salts and certain other substances can act as the co-ferment. The ferment 

 proper is practically insoluble in water, and is destroyed by boiling. If the 

 pancreatic extract be filtered, neither the precipitate nor the filtrate has any 

 appreciable action on fats ; but when the two are mixed the original lipolytic 

 action is recovered. The precipitate is the ferment ; the filtrate contains the 

 co-ferment. 



Preparation of an Emulsion of Fat. Commercial olive oil (which 

 contains some free oleic acid) is treated in a flask with i drop of a i per cent, 

 alcoholic solution of phenolphthalein for every 10 cc. of oil. Decinormal 

 sodium hydroxide is added, with frequent shaking, till the mixture is slightly 

 alkaline, as shewn by a very faint pink tinge. A very stable emulsion is thus 

 formed, and thus a considerable surface of fat is exposed to the action of the 

 ferment. 



Fat-splitting action of lipase (steapsin). 



167. Label three test-tubes A, B, and C. 



To A add 2 cc. of the pancreatic extract and i cc. of water. 

 ,, B ,, , boil and add i cc. of 



water. 

 C and i cc. of i per cent. 



bile salts. 



It is advantageous to have the tubes fitted with well-fitting rubber 

 stoppers. To each add 5 cc. of the emulsion of oil, shake thoroughly, 

 and place in a water bath at 40 C. for i hour. Shake the tubes 

 thoroughly every fifteen minutes. At the end of the digestion 

 transfer the contents to three labelled beakers. Add 10 cc. of 96 

 per cent, alcohol to the tube, shake well, and transfer the alcoholic 



