ROBERT RUSSELL BENSLEY 29 



As in the marmot, so in the squirrel and gopher (Spermophilus citillus) do the 

 glands of Brunner, according to Oppel (1897) extend a considerable distance beyond 

 the point where the common bile duct enters the duodenum. 



In the red squirrel (Sciurus hudsonicus) I have traced the glands for a distance 

 of 24.6mm. from the pyloric sphincter. In the specimen from which this measure- 

 ment was taken the glands, for a distance of 8.3 mm., formed a compact mass, in which 

 separate lobules could not be made out, completely filling the tela submucosa. For a 

 further distance of 6.45 mm. the lobules were distinct, each lobule corresponding to 

 a group of ducts. For the last ten millimeters only scattered small lobules were 

 found, each consisting of a few acini, opening into the bottom of a gland of Lieber- 

 kuhii. 



The glands of Brunner in the squirrel make their appearance at the point oppo- 

 site the pyloric sphincter where the intestinal epithelium succeeds the gastric 

 epithelium. At this point they are located both in the tunica mucosa and the tela 

 submucosa, the former group being a direct continuation of the pyloric glands. The 

 lamina muscularis mucosae of the intestine at this point is very imperfect, so that the 

 lobules of the two groups are continuous, the fibers of the muscular lamina being dis- 

 persed among the lobules of the glands of Brunner. Beyond the first five millimeters 

 the lobules which are seen in the tunica mucosa are less numerous and are mainly 

 ducts which have subdivided before penetrating into the submucosa. 



In one specimen examined by the writer, comprising 10 mm. of the duodenum, 

 the ducts of the glands of Brunner were independent of the glands of Lieberkuhn and 

 were lined throughout by cells similar to those of the glandular tubules. In a second 

 specimen, in which the pyloric glands extended a distance of 1 mm. into the duo- 

 denum, the proximal group of glands of Brunner opened, together with the pyloric 

 glands, by means of the gastric foveolae. Beyond the point where the first gland of 

 Lieberkuhn made its appearance independent ducts were rare, the ducts opening into 

 the glands of Lieberkuhn either as soon as they entered the tunica mucosa, or at 

 various levels between that point and the middle of the layer. The scattered lobules 

 of the lower 10 mm. of the zone opened exclusively into the bottoms of the glands of 

 Lieberkuhn. 



The cells composing the glands of Brunner in the squirrel are subcylindrical in 

 shape and from 15. 9 p to 17.2/4 in height. The large spherical or elliptical nucleus, 

 placed in the proximal half of the cell, is surrounded by a considerable basal layer of 

 cytoplasm. The inner half of the cell is clear and coarsely reticular. The subdivision 

 of this distal clear segment of the cell into two secondary clear zones by a band of 

 cytoplasm stretching across the cell from side to side is very obvious in many of the 

 cells of the glands of Brunner of the squirrel. 



The secretion in the glands of Brunner is very easily stained, even over-ripe solu- 

 tions of hsematoxylin giving successful results. In stronger muchsematein it stains 

 intensely, and in such preparations presents the appearance of a coarse-meshed net- 



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