THE PANCREATIC JUICE 707 



the presence in the juice of a second ferment maltase which converts 

 the disaccharide maltose into the monosaccharide glucose. The juice in 

 the gut is therefore able to effect the further digestion of the products 

 of salivary digestion. On the other disaccharides pancreatic juice is without 

 effect. It contains no invertase, nor does it, in spite of certain statements 

 to the contrary, ever contain lactase. It has therefore no effect on either 

 cane sugar or milk sugar. 



THE ACTION OF PANCREATIC JUICE ON FATS 

 Fresh pancreatic juice contains a strong lipase or fat- splitting ferment, by 

 means of which, in the presence of water, neutral fats, e.g. the triglycerides of 

 palmitic, stearic, and oleic acids, are broken up into glycerin and the corre- 

 sponding fatty acids. This ferment is active either in alkaline, neutral, 

 or very slightly acid reaction. -If the reaction be alkaline the fatty acids 

 produced by the lipolysis combine with the alkali present with the formation 

 of soaps. The ferment may be obtained from extracts of the fresh gland, but 

 is rapidly destroyed if active trypsin be present. It is also contained in some 

 of the dried commercial preparations of trypsin. It is apparently insoluble 

 in distilled water, and is therefore found in the residue after extracting these 

 commercial preparations with water. It is easily soluble in glycerin. The 

 velocity with which lipolysis occurs is much increased (four to five times) by 

 the addition of bile. This adjuvant action of bile is not destroyed by boiling, 

 and is due entirely to the bile salts. These act in two ways. In the first 

 place, by their physical qualities they diminish the surface tension between 

 water and oil, so enabling a closer contact to be effected between the watery 

 solution contained in the juice and the oil which is presented to it. Moreover 

 they may aid in the solution of the ferment itself. In the second place, bile 

 salts have a solvent action on soaps as well as on fatty acids in slightly acid 

 medium. Bile may be regarded therefore as a favourable excipient or 

 medium for the interaction of the lipase and the neutral fats. The lipase of 

 pancreatic juice will also hydrolyse the esters of the fatty acids, such as 

 ethyl butyrate or monobutyrin. On the phosphorised fats or phosphatides, 

 such as lecithin, its action is still a subject of doubt. According to certain 

 authors extracts of the pancreas have the power of splitting off choline from 

 lecithin. It is not known whether the same property is present in pancreatic 

 juice itself, or whether any other dissociations are brought about in the 

 complex molecule of lecithin under the action of this digestive fluid. 



THE SECRETION OF PANCREATIC JUICE 



In order to study the relation of the secretion of pancreatic juice to the 

 other processes of digestion, observations must be carried out on an animal 

 with a permanent pancreatic fistula. 



Such a fistula was established by Claude Bernard by bringing the duct of the pancreas 

 to the surface and inserting into it a lead or silver tube. The arrangement was, however, 

 unsatisfactory since after a few days the tube dropped out and the natural course of 

 the duct from pancreas to intestine was restored. In order to avoid the disadvantages 



