460 



DISSECTION OF THE ABDOMEN. 



wards from that spot, till at the lower part of the jejunum they become 

 irregular in form, and may consist only of small roundish masses. 



The mucous membrane over them is hollowed into pits (fig. 152, 6), 

 and is generally destitute of villi on the subjacent follicles (fig. 153, A ), 

 but between the pits it has the same characters as in other parts. 



Fig. 153. 



<D 



bfl 



o 

 O 





cc 



0. 



A. A PIECE OF Mucors MEMBRANE ENLARGED, with its villi and tubules. Part of a patch of 

 Peyer's glands is also represented with the follicles (a), each having a ring of tubes at the cir- 

 cumference. B. A "solitary gland" of the small intestine, also enlarged, covered by villi 

 (Boehm). 



A patch, when examined by the microscope, appears to be but a collec- 

 tion of lymph follicles like the "solitary glands" (fig. 153), which are 

 round or oval in form, and are covered by the mucous membrane. Around 

 each follicle is a ring of apertures of the crypts before described. The 



follicles have the same composition as the 

 scattered " solitary glands." 



Fine arterial twigs (fig. 152, B ) ramify 

 on the follicles, and send inwards capillary 

 offsets which form a network in the inte- 

 rior, and converge to the centre. Lacteal 

 vessels form plexuses around and beneath 

 the follicle, but do not penetrate the wall. 



The Glands of B runner (fig. 154, i) are 

 small compound bodies, similar to the buc- 

 cal and labial glands of the mouth, which 

 exist in the duodenum. For a few inches 

 near the pylorus they are most numerous, 

 and there they are visible without a lens, 

 being nearly as large as hemp seed. The 

 glands consist of lobules, with appertaining 

 excretory tubes : and each ends on the sur- 

 face of the mucous membrane by a duct 

 (c), whose aperture is slightly larger than 

 the mouths of the contiguous crypts of 

 Lieberkiihn ; they secrete mucus. 



Epithelium. The epithelial lining of the 

 mucous membrane of the small intestine is 

 of the columnar or cylindrical kind. On 

 the villi it forms a distinct covering of 

 elongated pieces. It sinks into the crypts 



MAGNIFIED VIEW OF THE Mucous 

 MEMBRANE OF THE DUODENUM, with 

 the tubules of LieberkUhn and a 

 gland of Brunner. 



. Tubules. 



6. Gland of Brunner. 



c. Duct of the gland. 



d. Submucous layer of muscular fibres 



(KOlliker),. 



