254 ACTION OF THE PANCREATIC JUICE. 



by heat into a white mass. In the cold, there separates a jelly-like albuminous- 

 coagulum. Nitric, hydrochloric, and sulphuric acids cause a precipitate ; while the 

 precipitate caused by alcohol is redissolved by water. CI. Bernard found in the 

 pancreatic juice of a dog 8*2 per cent, of organic substances, and 0*8 per cent, of 

 ash. The juice (dog) analysed by Carl Schmidt contained in 1000 parts : 



f Sodic chloride, , . . 7 "36 



( Organic, . 

 Solids, 90-38 in \ Inorganic, . 

 1000 parts. 1 (like those of 

 ( blood-serum). 



The more rapid and more profuse the secretion, the poorer it is in organic substances, while 

 the inorganic remain almost the same ; nevertheless, the total quantity of solids is greater than 

 when the quantity secreted is small (Bernstein). Traces of leucin and soaps are present in the 

 fresh juice. [It usually contains few or no structural elements. Any structural elements 

 present in the fresh juice, as well as its proteids, are digested by the peptone-forming ferment 

 of the juice, especially if the latter be kept for some time. If the fresh juice is allowed to stand 

 for some time, and then mixed with chlorine water, a red colour is obtained.] 



Concretions are rarely formed in the pancreatic ducts ; they usually consist of calcic carbonate. 

 Dextrose has been found in the juice in diabetes, and urea in jaundice. SchifFs statement that 

 the pancreas secretes only after the absorption of dextrin, has not been confirmed. ^ The secretory 

 activity of the pancreas is not dependent on the presence of the spleen, 



170. ACTION OF THE PANCREATIC JUICE. The presence of at least 

 four enzymes, or hydrolytic ferments, makes the pancreatic juice one of the most 

 important digestive fluids in the body. 



I. Diastatic action is due to the diastatic ferment, amylopsin, a substance 

 which seems to be identical with the saliva ferment ; but it acts much more 

 energetically than the ptyalin on saliva, on raw starch as well as upon boiled 

 starch ; at the temperature of the body the change is effected almost at once, 

 while it takes place more slowly at a low temperature. Glycogen is changed into 

 dextrin and grape-sugar ; and achroodextrin into sugar. Even cellulose is said to be 

 dissolved, and gum changed into sugar by it, but inulin remains unchanged. 



According to v. Mering and Musculus, the starch (as in the case of the saliva, 148) is 

 changed into maltose, and a reducing-dextrin ; so also is glycogen. Amylopsin changes 

 achroodextrin into maltose ; at 40 C. maltose is slowly changed into dextrose, but cane-sugar 

 is not changed into invert-sugar. The ferment is precipitated by alcohol, while it is extracted by 

 glycerine without undergoing any essential change. All conditions which destroy the diastatic 

 action of saliva ( 148) similarly affect its action, but the admixture with acid gastric juice (its 

 acid being neutralised) or bile does not seem to have any injurious influence. This ferment is 

 absent from the pancreas of new-born children (Korowin). 



Preparation. The ferment is isolated by the same methods as obtain for ptyalin ( 148) ; but 

 the tryptic ferment is precipitated at the same time. The addition of neutral salts (4 per cent, 

 solution), e.g., potassium nitrate, common salt, ammonium chloride ; increases the diastatic 

 action. 



II. Tryptic action, or the action on proteids, depends upon the presence of a 

 hydrolytic ferment which is now termed trypsin (Kuhne). Trypsin acts upon 

 proteids at the temperature of the body, when the reaction is alkaline, and changes 

 them first into a globulin-like substance, then into pro-peptone or albumose, and 

 lastly into a true peptone, sometimes called tryptone. The albumoses are not so 

 abundant or so easily separated as in gastric digestion (see also p. 248). The pro- 

 teids do not swell up before they are changed into peptone, [but they are eroded 

 or eaten away by the action of the juice]. When the proteid has been previously 

 swollen up by the action of an acid, or when the reaction of the medium is acid, 

 the transformation is interfered with. 



Substances yielding gelatin, nuclein, and Hb, resist trypsin ; glutin and swollen-up gelatin- 

 yielding substances are changed into gelatin-peptone, but the latter undergoes no further 



