518 DIGESTION. 



has an acid reaction from the presence of fatty acids, liberated 

 by the ferment from the fats in the pancreas, and is opalescent 

 from the presence of fat in a state of emulsion. Boil a little of 

 the fluid ; a precipitate of albumin is formed. Filter, and neu- 

 tralize by acetic acids, and a further precipitate of alkali-albu- 

 minate will be produced. The presence of leucine and tyrosine 

 may be shown by removing the albumin by boiling and acidu- 

 lat iiiir. and then separating them as described in 35. To show 

 that leucine is present in the juice as secreted, and is not due 

 to changes in it afterwards, it must be received in alcohol as it 

 flows from the fistula. 



* 167. Glycerin Solution of Pancreatic Ferments. 

 After cutting up the pancreas, as in the previous experiment, 

 lay it for a day or two in absolute alcohol, and after express- 

 ing the alcohol let it lie several days in glycerin, then filter. 



** 168. Actions of Pancreatic Juice. It emulsionizes 

 /V//.__Shake up some of the watery extract with olive oil, an 

 emulsion is formed. This is due to the albumin it contains, 

 for by adding liquor potassae to the mixture so as to dissolve 

 the albumin, and shaking, the drops of fat may be made to 

 run together again. 



2. It decomposes /<>//*, liberating Fatty Acids. The extract 

 of pancreas contains fat: hence when it is kept for an hour in 

 the water-bath at 40 C., without any addition, its acid reac- 

 tion increases. To show its action on fats, carefully neutralize 

 some of the watery extract and add to it a little olive oil or 

 fresh butter, whose reaction must also be neutral. Put the 

 mixture in the water-bath for some time, put a drop from the 

 bottom of the tube on blue litmus paper and let it run off. A 

 red and somewhat greasy spot is left. 



3. // ro/Hvr/.s Starch into Sugar. Mix some of the extract 

 with starch mucilage and let it stay for some minutes in the 

 water-bath at 40 C. ; then apply Trommer's test, and sugar 

 will be found. 



4. // ///f/rs/.s Fibrin, forming Peptones, and afterwards de- 

 r</////,os,'x /Ac//;, Leucine and Tyrosine being produced. Before 

 dissolving boiled fibrin, the pancreatic juice converts it into a 

 soluble albuminous substance, very much like raw fibrin. This 

 is then dissolved and is present in solution, either as albumin, 

 coagulable by heat, or as an albuminate. The dissolved albu- 

 min is next converted into peptones. If the digestion is 

 allowed to go on, the quantity of peptones in the solution 

 diminishes, while that of leucine and tyrosine increases. Bodies 

 which give the reaction of naphthilamine and indol (Kiihne) 

 are also formed, and when the digestion goes on for a long 

 time the indol is formed in considerable quantities, and emits, 

 a most disagreeable ficcal odor, which was attributed to putre- 

 faction till Kuhne showed its true nature. Boil several bits of 



