LESSON XVII. 



INTESTINE. BILE. PANCREATIC JUICE. 



A. STRUCTURE OF INTESTINE. 



The outer coats of the intestine have the same general 

 characters as those of the stomach (Lesson xvi. A, 1, 

 a d), except that there is no oblique muscular layer. 



1. Prepare vertical sections of a cat's or dog's small 

 intestine hardened in chromic acid *2 p. c. (cp. 

 p. 33 F 2). Stain with hsematoxylin (the 

 tissue may be stained before sections are made 

 by placing it in dilute hsematoxylin for a day). 

 Observe in the mucous coat 



a. The projections of the mucous membrane, or 

 villi, either extended and long, or contracted 

 and short with the surface thrown into folds. 

 Note 



c. The epithelium, consisting of rather long 

 columnar cells, each with a clear free 

 border more or less distinctly striated 

 with vertical lines, rather granular cell- 

 substance, and oval nucleus placed at 

 about the lower third of the cell; the 



