502 DIGESTION. 



and glycerin, which is an enzymotic process; and secondly, it has also 

 the property of emulsifying the fats. 



The action of the pancreatic juice in splitting the fats may be shown 

 in the following way: Shake olive-oil with caustic soda and ether, 

 siphon off the ether and filter if necessary, then shake the ether repeatedly 

 with water and evaporate at a gentle heat. In this way is obtained a 

 residue of fat free from fatty acids, which is neutral and which dissolves 

 in acid-free alcohol and is not colored red by alkanet tincture. If such 

 fat is mixed with perfectly fresh alkaline pancreatic juice or with a freshly 

 prepared infusion of the fresh gland and treated with a little alkali or 

 with a faintly alkaline glycerin extract of the fresh gland (9 parts glyc- 

 erin and 1 part 1 per cent soda solution for each gram of the gland), 

 and some litmus tincture added and the mixture warmed to 37 C., 

 the alkaline reaction will gradually disappear and an acid one take its 

 place. This acid reaction depends upon the conversion of the neutral 

 fats by the enzyme into glycerin and free fatty acids. A very much 

 used method consists in determining the acidity of the mixture by means 

 of titration before and after the action of the juice or the infusion. 



The action of the pancreatic juice in splitting fats is a process analo- 

 gous to that of saponification, the neutral fats being decomposed, by 

 the addition of the elements of water into fatty acids and glycerin 

 according to the following equation. CaHs.Oa.Rs (neutral fat)+3H 2 O = 

 C 3 H 5 .03.H3 (glycerin) +3 (H.O.R) (fatty acid). This depends upon 

 a hydrolytic splitting, which was first positively proved by BERNARD 

 and BERTHELOT. The pancreas enzyme also decomposes other esters, 

 just as it does the neutral fats (NENCKI, BAAS, LOEVENHART 1 and 

 others). The fat-splitting action of the lipase is, according to PAW- 

 LOW, BRUNO and many others 2 aided in its action by the bile. ROSEN- 

 HEIM and SHAW-MACKENZIE found that the lipase action was accel- 

 erated by hsemolytic substances, as well as by normal serum; this 

 accelerating action was inhibited by cholesterin. The accelerating 

 substance of the serum was dialyzable and resistant to heat. ROSEN- 

 HEIM was able to. divide the lipase existing in a glycerin extract of the 

 pig pancreas into enzyme and co-enzyme (page 52); in diluting with 

 water a precipitate occurred which contained the real thermolabile 

 enzyme while the dialyzable, heat resisting co-enzyme remained in the 



1 Bernard, Ann. de chim. et physique (3), 25; Berthelot, Jahresber, d. Chem., 

 1855, 733; Nencki, Arch. f. exp. Path. u. Pharm., 20; Baas, Zeitschr. f. physiol. Chem., 

 14, 416; Loevenhart, Journ. of Biol. Chem., 2; Terroine and Z. Morel, Compt. rend, 

 soc. biol., 65, 66. 



2 Bruno, Arch, des scienc. biol. de St. Petersbourg, 7; see also Loevenhart and 

 Souder, Journ. of biol. Chem., 2; v. Fiirth and Schiitz, Hofmeister's Beitrage,9; Ter- 

 roine, Bioch. Zeitschr. 23; Compt. rend. soc. biol. 68, 439, 518, 666, 754 (1910). 



