3'2 THE STBUCTUBE OP THE GLANDS OP BKUNNEB 



ous layer in the submucosa, except at the end of the zone, where the glands termi- 

 nated as scattered small lobules. The ducts emptied into the glands of Lieberkuhn. 



The differences between the cells of the glands of Brunner and those of the 

 pyloric glands were greater in this animal than in any other mammal examined. The 

 former cells were large, transparent, 15-17 /t in height, completely filled with secre- 

 tion without any indication of subdivision into two masses. The nucleus was crescentic 

 and placed in the base of the cell. The cells of the pyloric glands were small, 9 p in 

 height, contained very little secretion, and possessed a relatively large oval nucleus. 

 The secretion contained in both kinds of cells stained readily in muchaeuiatein and 

 mucicarmine. 



In the white rat the glands of Brunner begin abruptly as a mass of considerable 

 thickness occupying the space formed by the sudden falling off in thickness of the 

 muscular coat on the dorsal side of the sphincter pylori. According to Kuczynski 

 (1890), they extend into the duodenum a distance of 4.2 to 9 mm. In one specimen 

 measured by the writer the extent was 5.5mm. The greatest thickness of the mass 

 is exhibited at the very beginning of the zone, where they reach a thickness of 1 mm. 

 From this point onward the zone rapidly diminishes in thickness and, beyond a point 

 3mm. to 3.5mm. from the sphincter, is only represented by scattered small lobules. 

 Throughout the zone the lamina muscularis mucosse is defective. The glands discharge 

 into the glands of Lieberkuhn. 



The cells of the glands of Brunner of the rat have recently been the subject of a 

 careful study by Castellant. This author finds that the glands of Brunner of the rat 

 present no anatomical relation to the pyloric glands and that the study of their fine 

 structure places them still farther apart. He describes the cells as follows: "Leurs 

 cellules secretantes, de forme pyramidale presentent un contenu divise en deux zones; 

 IHine basale, granuleuse, ou se trouve le noyau ; 1'autre, apicale qui reste claire, quelque 

 soit le liquide fixateur employe^ alcool, liquide de Flemming, acide osmique." He found 

 that staining with hsematoxylin after Flemming's fluid did not color the clear zone of 

 the glands of Brunner. Mayer's mucicarmine also, in Castellant's hands, gave negative 

 results, but thionin staining after treatment with acetic acid gave a faint reddish color 

 which he thought might be interpreted as revealing the presence of a little rnucin. 



Castellant also studied the mechanism of secretion in the cells of the glands of 

 Brunner of the rat in preparations fixed in Flemming's fluid. He found that for the 

 first two hours of digestion these cells increase in size, the apical clear zone increases 

 in size, and the basal granular zone is diminished in amount. From the third hour of 

 digestion onward he found a progressive reduction in the amount of secretion in the 

 cell to the end of the seventh hour, when the cell is almost wholly granular and con- 

 tains little secretion. 



Castellant does not specify the exact nature of the differences which he found 

 between the pyloric gland cells and those of Bruuner's glands, but it may be inferred that 

 the clear subdivision of the cell into two zones in the glands of Brunner is one of them. 



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