ivIUCOUS MEMBRANE OF LARGE INTESTINE. [sect. 156. 



§ 156. Mucous Membrane of the Large Intestine. — The large 

 and small intestines agree in the structure of their mucous mem- 

 brane in so many essential characters, that it will suffice to call 

 attention to some few points of difference. 



The large intestine, with the exception of the rectum, has no 

 proper folds ; for the fibres of the transverse layer of the muscular 

 coat also enter into the plicce sigmoidea. The villi are likewise 

 entirely absent, from the sharp border of the valvules Bauhini on- 

 wards, into which valve, also, the muscular coat enters ; and the sur- 

 face of the mucous membrane, apart from the small, scarcely per- 

 ceptible, papilliform elevations at particular places, is even and 

 smooth. The muscular layer of the mucous membrane of the colon is, 

 in man, with difficulty perceptible, but is decidedly present ; in the 

 rectum, on the other hand, it is more distinct. In animals, I 

 observe that it is very well developed. According to Brit eke } the 

 longitudinal and transverse muscular layers of the mucous mem- 

 brane of the colon (of animals?) are together only 0013'" thick. 

 This is attributable to the outer longitudinal fibres, which are 

 reduced to three or even only two strata ; in the rectum, the layers 

 become again equally thick, both together about o - 022'", at the anus 

 even o - o88'" and more. According to Treilz, the muscular fibres 

 also enter into the columnce Morgagnii. 



The glandular structures of the large intestine are the Lieber- 



k ill a dan glands and solitary 

 follicles. The former, also 

 called glands of the large in- 

 testine, are found . everywhere, 

 from the Bauhinian valve as 

 far as the anus, and also in the 

 appendix vermiformis, closely 

 crowded together. They pre- 

 sent entirely the same structure 

 as those of the small intestine, 

 only they are longer and 

 broader {\'" to £■'" in length, 

 i§" *° 2V" m breadth), in 

 conformity with the greater 

 thickness of the mucous mem- 

 brane. Here, also, in man and 

 in animals, I observed thrOUgh- 



Fig. 145. 



Solitary follicle from the colon of a child ; mag- 

 nified 45 times, a. Tubular glands; 6. muscular 

 layer of the mucous membrane ; c. submucous 

 tissue ; d. transverse muscular fibres ! c. serous 

 membrane ; /. depression of the mucous mem- 

 brane over the follicle g. 



out in the fresh condition no morphological elements, except a 



