ABSORPTION OF FAT IN THE INTESTINES. 



whether, as Briicke supposes, the truth is rather that 

 the whole of this upper border is composed of little 

 rods or pillars resembling cilia. I must confess that my 

 own investigations also have rather disposed me to 

 adopt this latter opinion, especially as comparative his- 

 tology shows us real ciliated epithelium to be the equi- 

 valent structure in the same parts. At all events this 

 much is certain, that, a short time after digestion has taken 

 place, the fat no longer lies only outside, but is found 

 also inside, the cells, and first at their outer end ; then 

 it gradually advances farther and farther inwards in the 

 cells, and indeed so distinctly in rows, that it might 

 easily give rise to the impression, that fine canals ran 

 throughout the whole length of the cells themselves 

 (Fig. 109, C, a). But this too is a question which will 

 not, I think, with our present optical instruments, be so 

 very speedily settled. At any rate, the plain fact re- 

 mains, that the fat -passes through the cells, and this 

 indeed in such a way, that at first only their outer end 

 is filled with it, then a time comes when they are quite 

 full of fat, then a little later the outer part again be- 

 comes entirely free from it, whilst the inner still con- 

 tains a little, until at last all the fat entirely vanishes 

 from the cells. In this manner its gradual progress may 

 be followed from hour to hour. After the fat has ad- 

 vanced as far as the inner extremity of the cells, it 

 begins to pass into the so-called parenchyma of the 

 villus (Fig. 10$, C). Whether the epithelial cells have 

 an orifice below, and whether, as has been quite re- 

 cently maintained by Heidenhain junior, they are con- 

 nected with extremely minute canals formed by the con- 

 nective-tissue-corpuscles, is not quite decided, though it 

 is very probable. It is extremely difficult to come to 

 any definite conclusions with regard to these extremely 

 minute arrangements of the substance of tissues. In 



