ROBERT RUSSELL BENSLEY 81 



is on the distal side of the thickest portion of the sphincter. The lamina muscularis 

 mucosse is not present as a distinct layer throughout the zone, but is represented by 

 bands of smooth muscle running in various directions among the glands. The glands 

 of Brunner are so closely packed in the submucosa and deeper layers of the mucosa 

 that there is very little division into distinct lobules. The ducts open into the bottoms 

 or sides of the glands of Lieberkuhn. 



The glands have the usual shape and structure, i. e., are composed of repeatedly 

 branching tubules terminating in elongated pear-shaped acini or short tubules. The 

 whole system of ducts and branches is formed of similar cells. 



A transverse section of a tubule of a Brunner's gland from the muskrat is shown, 

 highly magnified, in Plate XXII, Pig. 9. The large lumen is surrounded by somewhat 

 cylindrical cells 13 /t to 17 M in height, filled with secretion. The secretion is more 

 or less obviously divided into a narrow distal and a larger proximal mass by a band of 

 cytoplasm. The nucleus is flattened or crescentic, and located in the extreme outer 

 end of the cell. 



In Plate XXII, Fig. 10 are shown two glands from the pyloric region of the 

 stomach drawn at the same magnification. The differences between this figure and the 

 preceding one are so apparent that they scarcely require comment. The cell of the 

 pyloric gland is much smaller, measuring 10.5/4 to 11.3/4. The secretion is confined 

 to a narrow band along the free border, and the rest of the cell is occupied by reticular 

 cytoplasm containing an oval nucleus rich in chromatin. Several cells of Stohr may 

 be seen. 



The secretion contained in the cells of the glands of Brunner and of the pyloric 

 glands stains readily in strong muchsematein ; that of the glands of Brunner staining 

 the deeper color. That this difference in the intensity of the staining does not mean 

 a greater concentration of the mucin in the two cells is indicated by the result obtained 

 in sections stained with Mann's methyl blue-eosin. In this the secretion contained in 

 the cells of the pyloric glands stains deep blue, that of the glands of Brunner pale blue. 



In the deer mouse the extent of the glands of Brunner, measured in one specimen, 

 was 2.6 mm. The cells of the glands differed from those of the muskrat in the specimen 

 examined in that the proximal mass of secretion was less compact than the distal mass, 

 and the segment of the cell in which it was located contained relatively more cytoplasm. 

 There was in addition a narrow basal layer of cytoplasm containing the slightly flat- 

 tened oval nucleus. The cells of the pyloric glands differed from those of Brunner's 

 glands in this animal in much the same way as in the muskrat. The pyloric-gland 

 cells were very small, had a relatively large oval nucleus, and contained but a small 

 amount of stored-up secretion. The secretion of both kinds of cells stained readily in 

 stronger muchaematein. 



In the dormouse examined (Muscardinus avellanarius) the glands extended a 

 distance of 3.5 mm. into the intestine. Throughout this region the lamina muscularis 

 mucosse was represented only by scattered fibers. The glands formed a thin continu- 



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