574 THE INTESTINAL CANAL, BY E. KLEIN AND E. VERSON. 



suggested that these structures were the results of the meta- 

 morphosis of the cylinder cells. It still remains doubtful, how- 

 ever, whether, as Henle* observes, these corpuscles are modified 

 epithelial cells or represent morphological elements of a peculiar 

 kind. The cylinder cells of the small intestine are structures of 

 such delicacy that they can only be examined in the fresh state, 

 without the addition of any reagents, and as they appear on 

 folds of the mucous membrane excised from the living animal, 

 the covering glass being very gently applied. It is only in pre- 

 parations thus treated that the intestinal epithelium is dis- 

 played ; it is only possible in this way to obtain a bird's-eye 

 view of the regular mosaic formed by the cells investing the 

 villi from their bases, and it is only thus that we can convince 

 ourselves that both terminal surfaces resemble one another, 

 varying only in their form and size. Even after the lapse of 

 a few minutes, clear bright spots make their appearance at the 

 bases of some of the villi, and in a short time goblet cells be- 

 come visible. The adjustment of the focus renders it evident 

 that these bright spots correspond to elevations which project 

 at various points to ^an unequal height above or beyond the 

 general level of the epithelium. Now, in regard to the occur- 

 rence of these elevations and the production of spheroidal 

 structures from columnar epithelial cells, already demonstrated 

 by Briicke from examination of cells in profile, there can be 

 no doubt that portions of the contents of these cells are thrown 

 off very quickly after their .removal from the living body, and 

 give rise to such cup-like structures. Strieker and Kocslakof 

 have pointed out that a process of this kind is extremely well 

 marked in acute catarrhal inflammation, the columnar epithe- 

 lium of the catarrhally affected stomach and intestine of the 

 rabbit, even in a fresh condition, presenting throughout tracts 

 of considerable extent cup-shaped cells alone. If we add to 

 this that it not unfrequently happens for the greater part of 

 the intestinal epithelium to become converted, after the action 

 of reagents into cup cells, we cannot in reason deny that the 

 latter may originate from the ordinary columnar cells. 



Handbuch der Eingcweidekhre, 1862, p. 165. 



