1880.] Hydrolytic Ferments of Pancreas and Small Intestine. 405 



converts with great readiness maltose into dextrose. Thus we see 

 that in the transition from colloidal starch to highly diffusible dextrose, 

 the hydrolytic actions of the pancreas and small intestine are mutually 

 dependent and complementary to each other, neither one set of actions 

 alone being sufficient. 



The small intestine does not contain a very active amylolijtic fer- 

 ment, because it is seldom or never called upon to act upon unaltered 

 starch, the first portion of the work being completed by the pancreatic 

 secretion. Briicke (" Wien. Sitzungsber.," 65 (3), 126), when experi- 

 menting upon dogs fed with amylaceous food, found that the soluble 

 starch and erythrodextrin which were produced in the stomach at once 

 disappeared on passing the pylorus, under the rapid action of the pan- 

 creatic juice. 



We have now to consider more fully the part played by the three 

 different sets of glands of the small intestine in bringing about the 

 hydrolytic effects which we have described. These glands are known 

 as — (1) the glands of Brunner; (2) the glands or follicles of Lieber- 

 kiihn ; and (3) the glands of Peyer. 



Brunner' s glands occur only in the duodenum. They are most 

 numerous immediately below the pylorus, and resemble closely in 

 structure the salivary glands, or minute portions of the pancreas. 

 When a portion of the duodenum containing these glands is mace- 

 rated in water, the liquid becomes extremely viscous, owing to the 

 extraction of the special glandular secretion. This effect is besb 

 •observed by taking the duodenum of an animal which has been killed 

 during digestion. The viscid secretion, resembling in appearance 

 submaxillary or sublingual saliva, ha* but a very slight amylolytic 

 action. The portion of the duodenum containing the glands has only 

 a very slight invertive action upon cane-sugar, but a somewhat more 

 decided hydrolytic action upon maltose. 



The glands or follicles of Lieberkuhn consist of tubular depressions 

 in the mucous membrane of the intestine, and are generally supposed 

 to secrete the succus entericus, to which, however, the Brunner's glands 

 must also largely contribute. Since Lieberkiihn's follicles are pretty 

 evenly distributed throughout the whole of the small intestine, and the 

 hydrolytic effect of equal areas of the intestine varies very much in 

 different parts, it is evident that these glands play no very important 

 part either in the inversion of cane-sugar or in the still more active 

 hydration of maltose to dextrose. 



We believe that the variable hydrolytic action of the different 

 regions of the small intestine is mainly if not entirely due to the rela- 

 tive frequency of the glands of Peyer. The solitary Peyer's glands 

 occur most scantily in the upper portion of the duodenum, and here 

 the hydrolytic effect is by far the least. As the solitary glands in- 

 crease in number the action of the intestine becomes more strongly 



vol. xxx. 2 g 



