INTESTINAL ABSORPTION 



299 



As to the manner in which the fat enters the epithelium there 

 is some doubt. Schafer * suggested that the leucocytes by their 

 amoeboid activity inclose the emulsified droplets in the intestinal 

 lumen and convey them into the substance of the villi. It seems 

 more probable that the fats are saponified in the intestinal tract, 

 and, as such, enter the epithelium in solution. Here they are 

 again synthetized into neutral fat by the activity of the epithe- 

 lium (Pfliigerf). Such a process accounts for the abundance of 

 fat within the distal portions of the cells. The droplets are then 

 secreted into the intercellular and subjacent tissue spaces. 



The second phase of absorption includes the transference of 

 the fat particles to the lacteal. This process appears to depend 

 partially, at least, upon the activity of the leucocytes, as suggested 

 by Schafer, the particles of fat thus finding their way through 

 the diffuse lymphoid tissue. According to ReuterJ fat drop- 

 lets are found in the 

 tissue spaces as well as 

 in the lymphatic cor- 

 puscles of the diffuse 

 lymphoid tissue, a fact 

 which would seem to in- 

 dicate that other agen- 

 cies aid in the transit of 

 the fat from the epithe- 

 lium to the lacteal than 

 are accounted for by the 

 purely mechanical the- 

 ory of Schafer. 



The third phase in- 

 cludes the secretion of 

 the fat into the lumen 

 of the lacteal. This is, 

 at least partially, accom- 

 plished by the disinte- 

 gration of fat-laden leu- 

 cocytes which, by amoeboid motion, have found their way into the 

 lacteal. Other fat particles may possibly find their way into the 

 lacteal without the aid of the leucocytes, a process which may be 



FIG. 244. APEX OF AN INTESTINAL VILLUS OF A RAB- 

 BIT WHICH HAD BEEN FED WITH MILK. 



The fat droplets have been blackened by fixation 

 with picric acid and osmium tetroxid. The figure 

 shows the distribution of fat during certain stages 

 of absorption. Alum carmin stain. Highly mag- 

 nified. (After K. Heidenhain, from Oppel.) 



* Internat Monatsch. f. Anat. u. Physiol., 1885. 



f Arch. f. d. ges. Physiol., 1900. % Anat. Hefte, 1902. 



