218 INTESTINAL DIGESTION. 



intestine, the same intermediate processes are observed as occur in the action 

 of the saliva ; but the change in the intestine into glucose is very rapid. It 

 is stated that amylopsine is not present in the pancreas of the new-born 

 infant (Korowin) and that in early infancy before the second or third 

 month the pancreatic extract will not digest starch. 



As cane-sugar passes from the stomach into the duodenum, it is almost 

 instantly transformed into glucose. This fact, which has been observed in 

 the lower animals, has received confirmation in the case of intestinal fistula 

 in the human subject, observed by Busch. In this case, when cane-sugar 

 was introduced in quantity into the stomach, fasting, the fluid which escaped 

 from the upper end of the intestine contained a small quantity of glucose, 

 but never any cane-sugar. 



It now becomes a question whether the transformation of cane-sugar into 

 glucose be effected by the bile, the intestinal juice or the pancreatic juice. 

 The pancreatic juice and the intestinal juice are the two fluids which might 

 be supposed to have this effect ; for it has been repeatedly demonstrated that 

 the bile has of itself but little direct action upon any of the alimentary mat- 

 ters. This point was settled by the experiments of Busch upon the lower 

 end of the intestine, in his case of fistula. Matters introduced into this 

 lower opening came in contact with the intestinal juice only. He found 

 that cane-sugar exposed thus to the action of the intestinal juice was not 

 converted into glucose, but a large portion of it passed unchanged in the 

 fasces. 



Out of the body, the pancreatic juice is capable, if kept but for a short 

 time in contact with any of the saccharine principles, of transforming them 

 into lactic acid. The contents of the small intestine are sometimes alkaline 

 or neutral and are sometimes acid. When a very large quantity of sugar has 

 been taken, a part of it may be converted in the intestine into lactic acid, 

 and this may happen with the sugar which results from the digestion of 

 starch ; but under ordinary conditions, starch and cane-sugar are readily 

 changed into glucose and are absorbed without undergoing farther trans- 

 formation. 



Action of the Pancreatic Juice upon Nitrogenized Substances. Reference 

 has already been made to the great relative importance of intestinal diges- 

 tion ; and it has been apparent that the process of disintegration of food in 

 the stomach is not final, even as regards many of the nitrogenized substances, 

 but is rather preparatory to the complete liquefaction of these matters, 

 which takes place in the small intestine. In experiments in which the pan- 

 creas has been partially destroyed in dogs, there was rapid emaciation, with 

 great voracity, and the passage, not only of unchanged fats and starch, but 

 of undigested nitrogenized matter in the dejections (Bernard). The vora- 

 cious appetite, progressive emaciation and the passage of all classes of ali- 

 mentary substances in the fasces, after this operation, indicate the great im- 

 portance of the pancreatic juice in digestion ; but the precise mode of action 

 of this fluid upon the albuminoids is a question of some obscurity. If the 

 bile be shut off from the intestine and discharged externally by a fistulous 



