150 



MANUAL OF HISTOLOGY. 



really pass through, a regular cell-membrane or no has not yet been 

 ascertained. Cells which have puffed out under the action of water show 

 clearly the presence of a lateral membrane at least. 



However, it is nob alone the cylinder cells of the small intestine, but 

 also those of the gall-bladder and larger biliary 

 ducts, which possess these thickened lids per- 

 forated by canaliculi (Virchow, Friedreicli); the 

 same structures are said to have been encoun- 



Fig. 146. Cylinder - epithelium 

 from the small intestine of the 

 rabbit, a,, the cells in profile, 

 with the thickened border some- 

 . what elevated and traversed by 

 pores; 6, view of the same from 

 above, in which the orifices of the 

 little canals appear as dots. 



tered in the large intestine and other localities. 

 Columnar cells containing melanin have 

 neither been met with in man nor any other 

 mammal. 



Cylinder epithelium appears to undergo 

 in general but moderate physiological reno- 

 vation. The older views, according to which a 

 frequently repeated stripping of larger surfaces took place, have long since 

 been recognised as erroneous. 



Among these cylinder cells, but also between the elements of ciliary 

 epithelia and the soft slimy epidermis of the lower vertebrates, are to be 

 found certain peculiar elements which have been named "goblet-cells " 



(Becherzellen) (fig. 148 a). 

 They are sometimes dis- 

 posed without order, but at 

 other times possess a certain 

 regularity of arrangement. 

 They have usually the form 

 either of a plump, or more 

 or less slender flask or 

 wide-mouthed goblet, and 

 are destitute, of membrane 

 on their free surface. The 

 nucleus and protoplasm of 

 these elements is displaced 

 towards the lower pointed 

 extremity, while the other 

 half is occupied by a slimy 



mfflratt 



Fig. 147. The same cells. At a, the border has been 

 loosened by the action of water and slight pressure ; 6, view 

 of the cells in the normal condition; c, a part of the 

 thickened border is destroyed; d e f, the latter resolves 

 itself into separate columnar or prismatic pieces. 



substance, granular when in a fresh condition, but transparent in speci- 

 mens subjected to maceration. We look upon them as decaying cells 

 engaged in a process of slimy metamorphosis. 



REMARKS. The goblet-cells in question, known many years a^o to various 

 observers, have become lately the object of general attention, and have evoked, one 

 might almost say, a superabundance of treatises. This is no place to enter upon 

 a criticism of those works, but it may be observed that they regard the matter from 

 three different points of view : 1. Goblet-cells are epithelial elements en<m"ed in 

 Slimy metamorphosis. 2. They are independent formations, not derived from the 

 Drdinary epithelial cells. 3. They do not exist in the living body, and are purely 



artificial productions 



93. 



We turn now to the last modification of this clothing tissue represented 

 in ciliated epithelium. We understand by ciliated epithelium, a coating of 

 cells, sometimes single, sometimes laminated, which bear on their free ends a 

 varying number of small hair-like bodies endowed with a power of motion ; 

 these are the cilia. The fully developed cell is usually presented to us 



