THE DIGESTIVE TRACT. 



599 



during the process of absorption, are taken into the epithelia 

 between the rods, while others maintain that the rods themselves 

 take up the fat-granules. Above the columnar epithelia flat 

 endothelial formations have been described, constituting the 

 outermost investment of the connective tissue (Watney, Krause, 

 Debove). 



The manner in which liquids are taken up into the blood- and 

 lymph- vessels of the villus is by the active participation of the 

 columnar epithelia (Spina). During absorption, especially shortly 

 after fatty food has been eaten, the interior of the villi and also of 



1 



FIG. 256. VILLUS FROM THE SMALL INTESTINE OF A CAT. 

 VERTICAL SECTION. [PUBLISHED IN 1868.] 



A, myxomatous (so-called adenoid) tissue; in its center the lymph-vessel, bounded by 

 smooth muscle-fibers and filled with fat-granules ; F, cleft between the columnar epithelia, in 

 connection with the central lymph- vessel. Magnified 800 diameters. 



the covering epithelium is found to contain a large quantity of fat- 

 granules of different sizes, and the conclusion arrived at by Gruby 

 and Delafond was that the fat-granules were first taken up by 

 the epithelia, which convey them into the interior of the villus. 

 Since that time, most of the physiologists have attempted to 

 explain the absorption of fat from the basal surface of tfre epi- 

 thelia ; but the whole process is as yet an unsolved puzzle. We 



