THE LEUCOCYTES IN ORGANIC FUNCTIONS. 723 



do when the animal is fed with neutral fat." It seems clear, 

 from these and other available data, that the epithelial cells of 

 the villi capture fat-globules from the intestinal contents and if 

 need le convert this fat into neutral fats. 



We have seen, however, that the villi also take up the 

 leucocytes which ingest proteids. It is important, in this con- 

 nection, to clearly distinguish the two mechanisms involved 

 one from the other. Bohm and von Davidoff testify to the 

 passage of such cells into the villi by stating: "Leucocytes are 

 sometimes found within the epithelial cells, but more usually 

 between them, and, according to Stb'hr, when seen in these 

 positions are in the act of migrating into the lumen of the in- 

 testine." Stewart, however, remarks, in this connection: "Leu- 

 cocytes have been asserted to be the active agents in the ab- 

 sorption of fats. They have been described as pushing their 

 way between the epithelial cells, fishing, as it were, for fatty 

 particles in the juices of the intestine, and then traveling back 

 to discharge their cargo into the lymph. This view, however, 

 is erroneous." It is erroneous, but only in one respect, in our 

 opinion, i.e., their direct connection with the absorption of 

 fats, for, as stated, the functions of these wandering cells is 

 to carry proteids to the intravillous venules. These do not, 

 therefore, enter the intravillous lacteals. But other leucocytes 

 penetrate the latter with the neutral fat-globules. "Although 

 the leucocytes do not aid in the absorption of fat from the 

 intestine" says Stewart, "they appear to take it up from the 

 epithelial cells, conveying it through the spaces of the net-work 

 of adenoid tissue that occupies the interior of the villus, to dis- 

 charge it into the central lacteal, where it mingles with the 

 lymph." The distinction we suggest in this connection appears 

 to us to remove the confusion that exists in the literature of the 

 subject. Briefly, our conception of the process is as follows: 

 While the leucocytes which ingest proteids from the intestinal food- 

 stuffs pass between the epithelial cells and enter the venules, the leu- 

 cocytes which ingest fats only carry the latter from the inner limits 

 of {he epithelial cells to the interior of the lacteal, and deposit them 

 therein. 



Professor Foster expresses the opinion that the number 

 of leucocytes found to contain any appreciable degree of fat is 



46 



