STRUCTURE OF THE ORGANS OF ABSORPTION. 



349 



arranged as a mosaic, in part as pore-canaliculi, intended for the passage 

 of the finest fat-granules. As a matter of fact, however, this seam 

 belongs only to the longitudinal surfaces of the epithelial cells and is 

 comparable to the thickened edge of a cylindrical vessel, open above. 

 The protoplasmic cell-contents, which enclose a large elliptical nu- 

 cleus with nucleolus in the lower portion of the cell, end approximately 

 on a level with this edge, although at the same time, they contain, at the 

 level of the thickness of this marginal seam, many pseudopod-like proto- 

 plasmic processes, which, standing side by side, and arranged in bundles, 

 are surrounded by the edge of the marginal border. Thus, when viewed 

 from the side, the lid-membrane appears striated, while, as a matter 



FIG. 127. Structure of the Absorption-apparatus of a Villus: A, transverse section of a villus, in part ; a. cylindrical 

 epithelium, with thickened border (b); c, a goblet-cell; i, i, framework of the adenoid tissue of the villus; 

 d, d, cavity within this, in which lie lymphoid cells (e, e); f, central lymph-space in transverse section. B, two 

 cylindrical epithelial cells with extended pseudopod-like processes of the cell-protoplasm, participating in 

 absorption of the fat-granules. C, cylindrical epithelium after absorption of the fat-granules has been com- 

 pleted. D, cylindrical epithelium of the villus, viewed from the surface, with a goblet-cell in the center. 



of fact, neither the lid nor the mosaic plates or pores attributed to it 

 exist. The cells are, therefore, open toward the intestinal surface. 

 The protoplasmic processes, standing close together, and resembling the 

 cilia of ciliated epithelium, are directed from the interior of the cell 

 toward the periphery of the intestine. In their midst, near the free sur- 

 face, lies a diplosoma.' 



These protoplasmic processes are rapidly extended from the cell-body 

 beyond the edge of the cell-membrane, and in a manner comparable 

 to the pseudopods of amoebae, they seize the finely granular fat and 

 draw it into the cell-body. Moistening with bile appears especially to 

 promote their activity, as the movement is not observed in villi not 

 moistened with bile. 



