CH. xxvii.] THE LARGE INTESTINE. 453 



the inner circular. In the caecum and colon, the longitudinal 

 fibres, instead of being, as in the small intestine, thinly disposed in 

 all parts of the wall of the bowel, are collected, for the most part, 

 into three strong bands, which, being shorter, from end to end, 

 than the other coats of the intestine, hold the canal in folds, 

 bounding intermediate sacculi. On the division of these bands, the 

 intestine can be drawn out to its full length, and it then assumes 

 an uniformly cylindrical form. In the rectum, the fasciculi 



Fig. 387. Transvernc section of injected Peycr's patch (from Kolliker). The drawing wax 

 taken from a preparation made by Frey from the intestine of the rabbit : it represents 

 the fine capillary-looped network spreading from the surrounding blood-Teasels into 

 the interior of three of the lymphoid nodules. 



of these longitudinal bauds spread out and mingle with the other 

 longitudinal fibres, forming with them a thicker layer of fibres than 

 exists in any other part of the intestinal canal. The circular mus- 

 cular fibres are spread over the whole surface of the bowel, but 

 are somewhat more marked in the intervals between the sacculi. 

 Towards the lower end of the rectum they become more numerous, 

 and at the anus they form a strong ring called the internal 

 sphincter muscle. 



The mucous membrane of the large, like that of the small 

 intestine, is lined throughout by columnar epithelium, but, unlike 

 it, is quite destitute of villi, and is not projected in the form of 

 valvulce conniventes. Its general microscopic structure otherwise 



