ON 



INTER-CELLUUR BRIDGES 



IN 



COLUMNAR EPITHELIUM 



That the cells of some cellular tissues are united together by bridges 

 of protoplasm has long been held as a recognized fact. This led Heitz- 

 mann(i) in 1883 to consider the tissues as constituting so many cell colonies, 

 the individuals of which are ail dépendent, to a greater or less extent, the 

 one upon the other. 



The cell bridges were first noticed in stratified squamous epithelium 

 and for a long time that tissue was supposed to remain unique in this par- 

 ticular. The continuity of the spongioplasm of one cell with that ofanother 

 through the bridges has been reinvestigated as recently as 1892 by 

 E. Kromayer(2), who used a spécial method for its démonstration; and 

 more recently still, the bridges hâve been demonstrated in the outer root 

 sheath of the hair follicle, which is derived from the Malpighian layer of 

 the skin, by A. v. Brunn (3). 



In 1888 Kultschitzky(4) described similar bridges as uniting the fibres 

 of nonstriped muscle; he was the first to definitely distinguish them in this 

 tissue, though the discovery had been foreshadowed by Leydig (5) and by 



(1) Heitzmann : Mikroskopische Morpliologie des Thierkôrpers ; Wien, i883. 

 (z) E. Kromayer : T>ie Protoplasmafaserung der Epithel\elle ; Arch. f. mikr. Anatomie, 1892, 

 Bd. 39, p. 141. 



(3) A. v. Brunn : Zur Kenntniss der Haanvurçelscheiden ;] Arch. f.fmikr. Anat., 1894, Bd. 44, p. 207. 



(4) Kultscbitzky : Biologisches, Centralbl , 188S, Bd. VII, p. 572. 



(5) Leydig : Zelle und Gewebe; p. 127. 



