262 



ABSORPTION OF THE FOOD. 



absorption of fat by supposing that the greater part of it is emul- 

 sified by the action of the pancreatic juice, and, being thus broken 

 up into a state of extremely minute subdivision, the particles pass 

 into the villi, reach the lacteals, and by way of the thoracic duct 

 enter the blood-vascular circulation. In this theory the splitting 

 up of the fat plays the important part of aiding in the emulsifying 

 process (p. 101). Although fat-particles have often been observed 

 in the interior of the epithelial cells, they have never been seen 

 in the striated borders of these cells, which is a remarkable fact if 

 as fat they pass through these borders to reach the interior. Nor 

 is there any special reason why fat should be taken up by the 

 columnar epithelium more than any of the products of digestion. 

 It has been supposed that the lymph-corpuscles, already described 

 as existing between the epithelial cells of the villi, put out pseudo- 

 podia and take in the fat-particles, passing them on through the 

 reticular tissue of the villi (p. 223) ; but, as already stated, it is 

 in the columnar epithelial cells that the fat is seen during the 



FIG. 140. Longitudinal section through summit of villus from human small 

 intestine; X 900 (Flemming's solution): at a is the tissue of the villus axis; b, 

 epithelial cells; c, goblet-cell; d, cuticular zone (Bohm and > Davidoff). 



time of its absorption, and these are entirely distinct from the 

 lymph-corpuscles. 



