512 



SPECIAL HISTOLOGY. 



appear for the most part to be conical and flattened ; frequently, they 

 are even foliated or cylindrical, clavate or filiform, the three latter forms 



Fisr. 206. 



Fi^. 207. 







predominating in the Jejunum. The length of the villi is from 1-5-1-2 

 of a line ; the hreadth from 1-6-1-10, even 1-25 of a line ; the thickness 

 in the flattened forms 1-20 of a line. 



The villi are composed of two portions, a deeper, belonging to the 

 mucous membrane and an epithelial, superficial coat. The contour of 

 the former or villus proper, is similar to that of the entire villus; it is 

 simply a solid process of the mucous membrane, containing bloodvessels, 

 lymphatics and smooth muscles, whose matrix, through which a variable 

 number of roundish nuclei are scattered, in general exhibits no morpho- 

 logical character more decided than that of the mucous membrane itself, 

 yet must most undoubtedly be regarded as a metamorposed connective 

 tissue, without any intermixture of elastic tissue. The bloodvessels of the 



Fig. 20G. — Section through the walls of the lowest portion of a Calf's ileum, magnified CO 

 diameters: a, villi ; b, Lieberkiihn's glands; c, muscular layer of the mucous membrane; d, 

 follicles of a Pcyer's patch; c, remainder of the submucous tissue iinder them; /, circular 

 muscles; g, longitudinal muscles. 



Fig. 207. — Intestinal villus of a young Kitten without its epithelium, to which acetic acid 

 has been added ; «, boundary of the villus; b, subjacent nuclei; c, nuclei of the smooth mus- 

 cles; d, round nuclei in the centre of the villus. 



