34 THE STRUCTURE OF THE GLANDS OF BRUNNER 



The secretion of the glands of the pyloric region forms a narrow band along the 

 lumen which is much more compact in structure than the secretion in the glands of 

 Brunner, and like the contents of the theca in the gastric epithelium cell, retains some 

 color in sections stained in iron ha?matoxylin, in which the secretion of the Brunner's 

 glands are colorless. It also stains more intensely blue in Mann's methyl blue-eosin. 

 The basal cytoplasm is more granular in appearance, and the oval nucleus is larger 

 and richer in chromatin, than in the cells of the glands of Brunner. 



The glands of Brunner and the pyloric glands of the mouse correspond so closely 

 in structure and staining reactions with those of the rat, that they do not call for 

 special description. 



VI. THE GLANDS OF BRUNNER OF THE ARTIODACTYLA 



The topography of the glands of Brunner of the Ungulates has been recently 

 studied by Hock (1899). In the horse he found the glands to extend the enormous 

 distance of seven meters into the intestine. In the pig and the sheep two of the four 

 genera of the Artiodactyla examined by him they were also of considerable extent : 

 40 cm. in the six-weeks-old pig, and between 30 cm. and 40 cm. in the sheep. In a 

 young goat two or three weeks old he found the glands to extend only 4 cm. into the 

 duodenum. For the ox he gives no measurements. 



In my studies the Artiodactyla are represented by the sheep and pig, which are 

 especially interesting because they represent the two extremes of specialization of the 

 stomach of the recent Artiodactyla, and because they present differences in the relation 

 of the pyloric glands to the glands of Brunner which may be compared to those shown 

 by the Rodentia with simple stomachs and complex stomachs respectively. In the pig, 

 in which the stomach presents the simplest form found in the group, the two kinds of 

 glands resemble one another very closely ; in the sheep, with a highly specialized stom- 

 ach, the two kinds of glands are very different. They are further of interest because 

 of Kuczynski's failure to stain the secretion by any of the methods he employed. 



As far as the arrangement and topography of the glands are concerned, Hock's 

 excellent description leaves little to be desired. In the pig, according to him, the 

 glands of Brunner are the direct continuation of the enormously developed pyloric 

 glands, which at the summit of the pyloric sphincter begin to divide more freely and 

 extend more deeply, forming new lobules which completely fill the tunica mucosa and 

 open by short tortuous ducts into the foveola gastricse. Presently they exceed the 

 limits of the mucosa and extend over into and fill the submucosa. For about 1 cm., 

 according to Hock, the lamina muscularis mucossB is not present as a distinct layer, 

 but the fibers are dispersed among the lobules of the glands, to the muscular invest- 

 ment of which the pyloric sphincter also contributes fibers. For a distance of 20 cm. 

 from the pylorus the glands are described as forming a compact mass, completely filling 

 the submucosa. He finds that the ducts at the beginning of the zone discharge 

 into the gastric foveolss ; beyond the point of the first appearance of the glandulse 



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