XXV.] 



SMALL INTESTINE. 



275 



Villi 



with epi- 

 thelium. 



adenoid tissue in the submucous coat, then they present the appear- 

 ance seen in fig. 261. 



A solitary follicle exactly like one of the numerous follicles 

 which compose a Peyer's patch may be seen (fig. 262). 



3. Blood Vessels of 

 the Small Intestine. 

 Make a pretty thick 

 transverse section of a 

 well-injected small in- 

 testine (cat). Cut in 

 paraffin and mount in 

 balsam. 



(L) The mucous coat 

 is the most vascular 

 part ; the larger vessels 

 lie in the submucous 

 coat, and few vessels in 

 the muscular coat. 



(H) An artery runs 

 to the upper part of 

 each villus and gives 

 off a plexus of capil- 

 laries ; a vein on the 

 opposite side. A .rich ^. 

 plexus of capillaries < 

 between Lieberkiihn's 2 

 glands. If the section 

 pass through a solitary J 

 follicle, note that the -~ 

 capillaries pass into it 

 and form loops (fig. 

 262). 



The general distribu- 

 tion of the blood-vessels 

 is shown in fig. 263, 

 which shows how the 



FlG. 261. Longitudinal Section through a Peyer's Patch 

 OUS COats. of the Small Intestine of a Dog. 



4. Surface View of 



Injected Villi. To see the general arrangement of the blood-vessels 

 in the mucous membrane, inject the blood-vessels of a rabbit with 

 a red gelatine mass. Mount in balsam a part of the wall of the 

 small intestine, placing the mucous surface uppermost. 



(L) Xote the villi, and trace the artery to its origin from a larger 

 artery in the submucous coat (fig. 264) The artery runs on one 



Circular 

 muscle. 



Longi- 

 tudinal 

 muscle. 



