THE PANCREATIC JUICE. 151 



concentrated at a very low temperature, and the trypsin finally pre- 

 cipitated with strong alcohol. It is then rapidly filtered off and 

 dried. The amount of material which can thus be obtained from 

 one gland is always very small, but sufficient to digest a large 

 quantity of albumin when dissolved in about 100 c.c. of water. 



The so-called dry pancreas of Kuhne, from which trypsin can 

 likewise be obtained, and which is also used in digestive experiments 

 as such, is prepared by extracting the fresh gland with alcohol and 

 subsequently with ether until it is free from fats. The remaining 

 material, which contains the active ferment, is then dried and pul- 

 verized, and can be kept in this form indefinitely. 



The Amylolytic Ferment of the Pancreatic Juice (Amylop- 

 sin or Pancreatic Ptyalin). The amylolytic ferment of the pan- 

 creatic juice is by many thought to be identical with the ptyalin of 

 the saliva. It can be isolated, according to Gautier's method, from 

 an aqueous infusion of the fresh gland that has remained exposed to 

 the air for about twenty-four hours, as already described. To de- 

 monstrate its action, a few cubic centimeters of such an infusion, or 

 a glycerin extract of the gland, are added to a small amount of 

 starch paste and kept at a temperature of 40 C. The mixture is 

 then tested for the presence of dextrins and maltose, as already de- 

 scribed. 



Steapsin (Pancreatic Lipase). It has long been known that 

 the pancreatic juice possesses the power of emulsifying fats, and of 

 decomposing these into glycerin and the corresponding fatty acids. 

 This phenomenon was once referred to the action of bacteria, but is 

 now known to be referable to a specific lipolytic ferment, steapsin. 

 Of the nature of the ferment nothing is known, but it is manifestly 

 very unstable, as extracts prepared from glands that have been left 

 exposed to the air for twenty-four hours are perfectly inert when 

 brought in contact with neutral fats. Apparently it is digested 

 during this time by the trypsin. To demonstrate the action of 

 steapsin on fats, a small amount of perfectly fresh pancreas is finely 

 hashed and dehydrated with 90 per cent, alcohol. It is then dried 

 between filter-paper and placed in an ethereal solution of ethyl bu- 

 tyrate. On digestion at the temperature of the body the odor of 

 butyric acid will soon become manifest. Or, a small amount of 

 neutral fat is treated with a few cubic centimeters of a feebly alka- 

 line glycerin extract of the fresh gland (9 parts of glycerin and 1 

 part of a 1 per cent, solution for each gramme of the gland), to 

 which a few drops of tincture of litmus are added. If this mixture 

 is then kept at a temperature of 37 C., it will be noted that the 

 alkalinity gradually decreases, and the reaction finally becomes 

 acid, owing to the liberation of free fatty acids (Hammarsten). 



The emulsifying action of the pancreatic juice is owing to the 

 decomposition of the neutral fats, the subsequent saponifi cation of 

 the resulting acids by the alkaline salts which are at the same time 

 present, and the effect of the soaps thus formed upon the neutral 

 fats. 



