KOLLIKER, ON EPITHELIAL CELLS. 153 



and which must be regarded as cells in a state of regeneration, 

 ruptured at the upper end. 



To these facts Klilliker subjoins the f o\lo^Ymg possibiliiies 

 and suppositions, which he recommends as subjects for farther 

 research : 



1. The striae in the thickened cell-membrane are pore- 

 canals."^ 



2. Should this supposition prove correct, it would seem, in 

 the first place, proper to place these canaliculi in direct 

 relation to the absorption of fat ; though, at the same time, 

 it is also conceivable that they possess a more general signifi- 

 cance, and that they stand in a general relation to the 

 reception and secretion of material through cells. The former 

 view is supported by the circumstance — 



1 . That in many animals (herbivorous mammals, amphibia, 

 birds, &c.) the striated, thickened cell-membranes exist only 

 on the surface of the small intestine, whilst they are wanting 

 in its glands, as well as in the large intestine and stomach. 



2. The columnar and ciliated epithelium of other localities 

 presents no indication of the existence of a structure re- 

 sembling pore-canals. 



3. That the fatty matters are absorbed in the form of 

 molecules, so minute, as, at any rate, to be capable of pene- 

 trating through the canals in question. 



* In a note, KoUiker remarks tliat his supposed pore-canals have nothing 

 in common with t!ie imaginary pores stated by Keber to exist, not only in 

 epithelial cells, but in all other bodies. (Fide 'Quart. Journ. Micros. Soc.,' 

 vol. iii, p. 152.) 



