520 DIGESTION. 



purpose may be conveniently obtained by boiling a small piece 

 of grape sugar with nitric acid in a test-tube, and when the 

 tuhV is filled with red fumes emptying out the acid and filling 

 thr test-tube with water. 



* 169. Separation of the Pancreatic Ferments from 

 the Glycerin Extract. Precipitate the glycerin extract by 

 absolute alcohol; filter; treat the precipitate again for a week 

 or two with glycerin, and filter; let the filtrate fall drop by 

 drop into a tall cylinder filled with absolute alcohol. The 

 ferment is precipitated in white flocculi. After the precipita- 

 tion is complete, let it stand one or two days under a mixture 

 of alcohol and ether. Filter by means of Bunsen's pump, and 

 wash several times with alcohol and ether. Let the precipitate 

 dry over sulphuric acid, and then pulverize it (Hiifner). 



ITO. Isolation of the Pancreatic Ferments. Two of 

 the pancreatic ferments have been separated by Danilewsky ; 

 but that which splits up fat is removed or destroyed by the 

 magnesia he employs. His method is as follows: Wash the 

 pancreas of a dog which has been killed six hours after a full 

 meal thoroughly from blood, and rub it to a fine pulp in a 

 mortar, with about a quarter of its bulk of magnesia, and 

 four times its bulk of water. Put the mixture in a beaker, 

 and let it stand for two hours at 25 in the water-bath. After 

 it has cooled, and the pulp and magnesia have nearly subsided, 

 filter the fluid, but do not put the sediment on the filter, as it 

 chokes it, and, at the same time, partly passes through. Neu- 

 tralize the filtrate with dilute hydrochloric acid, and put it 

 into a flask large enough to hold three times as much. Pour 

 into it without stirring J-J of its volume of thick collodion, 

 and shake it sharply for several minutes, and repeat the shaking 

 several times. Pour the liquid into a large beaker, and stir 

 it constantly, so as to favor the escape of ether and prevent 

 the collodion from separating in large lumps. When the col- 

 lodion presents the appearance of small rounded granules, 

 filter through linen, and evaporate the ether from the filtrate 

 in vacua. Then treat the liquid with collodion a second time, 

 filter through the same piece of linen, unite both filtrates, and 

 put them aside (a) 



Wash the precipitate several times with spirit (60 to 70 per 

 cent.), and dry it without removing it from the linen between 

 double folds of blotting paper. Spread it out with a spatula, 

 and leave it exposed to the air till it is dry. Then shake it in 

 a tall narrow glass with ether, to which a little absolute alcohol 

 has been added, till the precipitate is dissolved and a turbid 

 solution obtained. Let it stand for two days, and then decant 

 the turbid fluid from the precipitate, and after diluting it with 

 Jther. pour it into two tall glasses and let it stand for several ' 

 days till a new precipitate subsides. Collect that which then 



