ABSORPTION. 



223 



breadth,; covering the surface of the mucous membrane from the 

 pyloric orifice to the upper surface of the ileo-cecal varve.j^Each 

 villus consists of a basement membrane (see Fig. 92) supporting tall 

 columnar epithelial cells. Each cell is composed of granular bio- 

 plasm containing a distinct nucleus. At its free extremity a narrow 



cZ' 



FIG. 92. LONGITUDINAL SEC- 

 TION or A VILLUS FROM IN- 

 TESTINE OF THE DOG, HIGHLY 

 MAGNIFIED. a. Columnar 

 epithelium containing goblet- 

 cells (&) and migratory leuko- 

 cytes (/z). c. Basement mem- 

 brane, d. Plate-like connec- 

 tive-tissue elements of core. 

 e, e. Blood-vessels. /. Ab- 

 sorbent radical or lacteal. 

 (Piersol.) 



e' 



FIG. 93. SECTION OF JNJECTED SMALL 

 INTESTINE OF CAT. a, b. Mucosa. 



f. Villi. i. Their absorbent vessels. 

 . Simple follicles, c. Muscularis mu- 

 cosas. ;. Submucosa. g, e r . Circular 

 and longitudinal layers of muscle. 

 /. Fibrous coat. All the dark lines 

 represent blood-vessels filled with the 

 injection mass. (Piersol.} 



border of the cell presents a striated appearance, as if it were com- 

 posed of small rods embedded in some cement substance. Goblet 

 or mucin-holding cells are also to be found among the columnar 

 cells. The body of the villus, that portion within the basement 

 membrane, consists of a reticulated connective tissue supporting 



