THE ABSORPTION OF FOOD. 



[CH. XXXIT. 



derived from the milk-like appearance of their contents (chyle) 

 during the absorption of fat. 



The way in which the minute fat globules pass from the 

 intestine into the lacteals has been the subject of much contro- 

 versy. The course they take may be studied by killing animals 

 at varying periods after a meal of fat and making osmic acid 

 microscopic preparations of the villi. Figs. 412 and 413 illustrate 

 the appearances observed by Professor Schafer. 



The columnar epithelium cells become first filled with fatty 



ttr- 



Fig. 412. Section of the villus of a rat killed during fat absorption, ep, epithelium; 

 str, striated border ; c, lymph-cells ; c', lymph-cells in the epithelium ; I, central lacteal 

 containing disintegrating lymph-corpuscles. (E. A. Schafer.) 



globules of varying size, which are generally larger near the free 

 border. The globules pass down the cells, the larger ones 

 breaking up into smaller ones during the journey ; they are then 

 transferred to the amoeboid cells of the lymphoid tissue beneath : 

 these ultimately penetrate into the central lacteal, where they 

 either disintegrate or discharge their cargo into the lymph 

 stream. The globules are by this time divided into immeasurably 

 small ones, the molecular basis of chyle. The chyle enters the 

 blood-stream by the thoracic duct, and after an abundant fatty 

 meal the blood-plasma is quite milky ; the fat droplets are so 



