SPLANCHNOLOGY 



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mucin which lubricates the mucous surface. These cells are found 

 in all mucous surfaces and prevent the surface from becoming dry. 

 There are a few goblet cells near the summits of the villi. Open- 



FIG. 37. Histological studies of various anatomical parts. 



A. A transverse section of the first portion of the esophagus of a fowl. I, 

 The outer longitudinal muscular layer. 2, The circular muscular layer. 3, The 

 submucosa. 4, The muscularis mucosa. 5, Stroma. 6, Epithelial layer. 7, 

 The lenticular glands. 8, The lumen. 



B. A transverse section of the proventriculus. i, The outer longitudinal 

 muscular layer. 2, The middle muscular layer. 3, The inner longitudinal mus- 

 cular layer. 4, Stroma. 5, The muscularis mucosa. 6, The submucosa. 7, 

 Stroma. 8, Tubular glands. 9, Tubulo-alveolar glands. 10, A tubulo-alveolar 

 gland with the tubular glands cut transversely, n, The lumen of the proven- 

 triculus. 



C. A section of the inner wall of the gizzard, i, The hyaline mucous mem- 

 brane. 2, Branched tubular glands. 3, Submucosa. 4, Muscle. 5, A con- 

 nective tissue septum. 



D. A transverse section of the small intestines, i, The outer longitudinal 

 muscular layer. 2, The inner circular muscular layer. 3, The muscularis 

 mucosa. 4, The stroma. 5, Brunner's glands. 6, A villus. 7, Mass of lym- 

 phoid tissue. 



E. A transverse section through the cecum. i, The outer longitudinal mus- 

 cular layer. 2, The inner circular muscular layer. 3, The submucosa. 4, The 

 muscularis mucosa. 5, The stroma. 6, Tubular glands. 7, The lumen. 



F. The cerebellum showing the arbo-vitae. i, White, fiber portion. 2, The 

 granular layer. 3, The layer of Purkinje cells. 4, The molecular layer. 



ings of simple intestinal tubular glands the duodenal glands, or the 

 glands formerly known as Brunner 's glands, are located between the 

 villi. These glands secrete the succus entericus, or intestinal juice. 

 These openings, or stomata, are lined with granular cells. The 



