ROBERT RUSSELL BENSLEY 21 



rupted by the ducts of the proximal lobules of the glands of Brunner. At this point 

 the pyloric glands and the glands of Brunner appear in places to be continuous. The 

 dispersed fibers of the lamina muscularis mucosse radiate out among the lobules of the 

 glands, forming a partial investment for them. At other points a duct which is pass- 

 ing through the muscularis mucosa? may give off a few gland tubules which are thus 

 located among the muscular fibers of the layer. 



The ducts of the glands of Brunner in the hedgehog are independent of the 

 glands of Lieberktlhn, between which they pass to open on the free surface. A 

 cluster of ducts from the proximal lobules occurs just at the junction of the intestinal 

 and the gastric mucous membrane, some opening between the gastric epithelium on 

 one side and the first villus on the other ; the rest, between the bases of the first short 

 villi. In the rest of the zone, the ducts occur at scattered intervals and pass through 

 the mucous membrane without branching or showing a change in type of the epithe- 

 lium. The glands are composed of richly branching tubules radiating from a central 

 duct in each lobule. The terminal branches are frequently short acinus-like tubules 

 which in fixed preparations, however, seldom show a terminal dilatation. 



The tubules are composed of large cells of rectangular or pyramidal shape, sur- 

 rounding a small lumen. The latter is larger in the tubules which are nearer the main 

 ducts and largest in the ducts themselves. The cells in the specimen from which the 

 descriptions are taken vary in length from 16 n to 21 /*, the average being 18 M. The 

 cells in hsematoxylin sections are clear, transparent, and filled with secretion, between 

 the droplets of which a delicate network may be made out. In the material at the 

 writer's disposal, very few of the cells of the gland tubules exhibit a subdivision of 

 the secretion into two masses. The nuclei are irregular and located at the bases of the 

 cells. In the ducts, on the other hand, the amount of residual protoplasm gradually 

 increases as the surface is approached, and the nucleus expands to an oval shape with 

 the long axis coinciding with that of the cell. In the stronger mucha3matein the con- 

 tained secretion stains deeply. 



The cells of the pyloric glands are very similar to those of the glands of Brunner, 

 although they are somewhat smaller (average length 15 /J-) and contain less mucin. 

 Cells of Stohr are frequent in the pyloric glands, but absent from the glands of 

 Brunner. The secretion in the cells of the pyloric gland, like that of the glands of 

 Brunner, stains with stronger muchaematein. 



V. THE GLANDS OF BRUNNER OF THE RODENTIA 



Among the rodents it is only in the suborder Myomorpha that the glands of 

 Brunner are confined to the proximal section of the duodenum, between the pylorus 

 and the opening of the ductus communis choledochus. In the rabbit, belonging to 

 the Duplicidentata, the American porcupine, belonging to the Hystricomorpha, and 

 the squirrel, marmot, and gopher (Oppel) belonging to the Sciuromorpha, they extend 

 far beyond the opening of the bile duct. 



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