THE INTESTINES. 107 



They are closely set, and have exactly the same structure as those 

 of the small intestine, only, in accordance with the greater thick- 

 ness of the mucous membrane, they are longer and broader 

 (i — $"' long, ± — J{". broad.) Here also I have found, in man 

 and in animals, in the fresh state, no formed contents besides a 

 beautiful cylinder epithelium; so that we have no reason to 

 suppose that the secretion is at all different from that in the 

 glands of the small intestine, especially as the mucous mem- 

 brane has, like that of the latter, an alkaline reaction, and, so 

 far as my own experiments go, is equally devoid of digestive 

 action. 



The solitary follicles are arranged close together in the 

 processus vermicular is, are very frequent in the ccecum and 

 rectum, and are also usually 



more abundant in the colon .^JUL 



than in the small intestine. 

 They are distinguished from 

 those of the latter locality by 

 their larger size (| — 1 — 1J'") 

 and by the circumstance that 

 upon each of the little 

 prominences of the mucous 

 membrane to which the folli- 

 cles give rise, there is a small 

 pit-like, elongated or rounded 

 aperture, of i — £"', which 

 leads to a little depression of the mucous membrane above the 

 follicles. These pits, which are totally absent in the normal 

 follicles of the small intestine, led Bohm formerly to regard 

 the follicles as csecal glands provided with apertures : this, how- 

 ever, is incorrect, for at the bottom of this depression lies, as 

 Briicke has also remarked, a closed, somewhat flattened follicle 

 of exactly the same structure, even to the internal vessels, as 

 those of the small intestine. 



The blood-vessels of the glands and follicles of the large 

 intestine present the same relations as in the small. Every 

 Lieberkiihnian aperture is encircled by a ring of vessels of 



Fig. 217. Solitary follicle from the colon of a Child, x 45 : a, Lieberkuhn's 

 glands; b, muscular layer of the mucous membrane; c, submucous tissue; d, trans- 

 verse muscles ; e, serous membrane ; /, depression of the mucous membrane above 

 th« follicle, a. 



