440 



ANATOMY OF VERTEBRATES. 



score may be found in the tract of the small intestine, situated 

 opposite the line of attachment of the mesentery, and most nu- 

 merous in the ileum, where the intestinal contents become less 

 342 dilute : rarely are any seen in the duo- 



denum. Viewed with a higher power, 

 as in fig. 343, the follicular orifice, a, is 

 surrounded by a circle of pores of the 

 1 intestinal tubules : ' and in the inter- 

 spaces of the clustered follicles project 

 short obtuse conical villi, b, of so much 

 smaller size than the ordinary ones as 

 to make the patch appear bare. The 

 looped capillaries of the follicle come 

 off from vessels encircling their cap- 

 sule. 



The ( racemose glands,' fig. 343, c, 

 are peculiar to the duodenum, and most 

 numerous at its commencement Avhere 

 they form a circular layer just beyond 

 the pylorus. Here each gland is about 

 T i^th of an inch in diameter. The duct 

 at the areolo-fibrous base of the intesti- 

 nal glands, fig. 344, a, divides and sub- 

 divides in the thick submucous tissue, 

 and ultimately terminates, or receives the secretion of numerous 

 subglobular or polyhedral follicles, averaging -^^th of an inch 

 in diameter: these answer to what are 

 termed the ( acini ' in larger glands : the 

 nature of their secretion has not been de- 

 termined : it, probably, resembles the pan- 

 creatic from analogy of structure. 



The ileum terminates in the side of the 

 beginning of the large intestine leaving a 

 short and wide sacculated * caecum ' from 

 near the end of which is sent off a slender 

 * vermiform appendage,' iig. 332, c C. The 

 human caecum is further characterised by its fixed position ; having 

 only a partial covering of peritoneum, which passing off from 

 its fore part binds it down to the ' iliacus interims ' muscle to 

 which its non-serous surface is connected by areolar tissue and 

 fascia. The intestine, as it rises from the caecum, is called 

 ( colon ' or « ascending colon,' ib. A c, and continues, as it passes 

 the right kidney and * quadratus lumborum,' to be attached 



Patch of agminate follicles, magu. 

 5diam.cxLVin". 



343 



Portion.of patch of agminate full 

 cles, magn. 12 diain. cxlviii". 



