2l6 



HISTOLOGY. 



4 to 6 months there are villi in the large intestine, but they disappear be- 

 fore birth, by becoming flattened out. The vermiform process is distin- 

 guished from the colon by its small diameter and by the abundance of 

 lymph nodules in its tunica propria. They are often confluent (Fig. 243). 

 In old age the lumen of the vermiform process is frequently obliterated; 

 this has been recorded in 50% of persons over 60 years old, and appears 

 to be a normal retrogression. The epithelium with its glands, and the 

 nodules disappear and are replaced by an axial mass of fibrous tissue. 

 This is surrounded by the unaltered submucosa, muscularis, and serosa. 



LARGE INTESTINE CAECUM AND COLON. 



The intestinal glands of the caecum and colon are longer than those 

 in the small intestine, sometimes twice as long (0.4-0.6 mm.). They 

 contain more goblet cells, but cells of Paneth are absent. Striated cutic- 



r , Glands. 



A 



Muscularis 

 mucosae. 



' Submu- 

 cosa. 



Fat cells. 



Solitary nodule with germinal center. 



FIG. 244. VERTICAL SECTION OP THE Mucous MEMBRANE OP THE DESCENDING COLOX 

 OP AN ADULT MAN. X 80. 



Compare the length of the glands with those of the small intestine (Fig. 230), from the same individual 

 and drawn under the same magnification. 



ular borders appear near the outlets of the glands and are well developed 

 upon the columnar cells lining the intestinal lumen. Solitary nodules are 

 numerous, especially in the caecum. Apart from the muscularis, the re- 



