QUARTERLY CHRONICLE OF MICROSCOPICAL 

 SCIENCE.! 



HISTOLOGY. 



IV. Epithelium. — Bizzozero (" On the Structure of Stratified 

 Pavement Epithelium," ' Moleschott's Untersuchungeii', vol. 

 xi, p. 30, 1872) discusses the bristle-like processes of epidermic 

 cells from the Malpighian layer, first observed by Schron, 

 and afterwards described by himself and Max Schultze. 

 Bizzozero had first adopted the explanation that the bristles 

 of adjacent cells interdigitate with one another, so as to attach 

 their cells more firmly together, but has lately been led to a 

 different conception. His observations were made partly on 

 normal epidermis (which he suggests the observer may con- 

 veniently obtain with a sharp razor from his own skin, as for 

 instance from the forearm), but better on the hypertrophic 

 epithelium of warts, ei)ithclial growths, &c. After harden- 

 ing in bichromate of potassium and alcohol, fine sections 

 Avere made which were stained in carmine and put up in 

 Dammar varnish. It then becomes apparent that the cells 

 are not absolutely in contact, but are se])arated from one 

 another by a pale border, which corresponds to a very minute 

 intercellular canal, so that the Avhole forms a canalicular 

 network in each mesh of whicii an epithelial cell is enclosed. 

 On examination with a higher power these canals are seen 

 to be crossed transversely by the rigid processes or bristles 

 which pass from one cell to the other. These bristles are 

 not, as Schultze supposed, in contact with one another, but 

 separated by intervals which in normal skin, &c., are not 

 wider than the bristles themselves, but in hypertrophic 

 epidermis are sometimes two or three times as large. These 

 intervals are very evident when instead of a profile or sec- 

 tional view the surface of the cell is examined. The inter- 

 cellular spaces are of course not really canals, though appear- 

 ing as such in sections, but correspond to the shape of the 

 cells. What substance is contained in these passages could 

 not positively be made out, but Bizzozero believes that they 

 serve to carry nutritive fluids to the non-vascular epidermis 

 or stratified epithelium. 



^ The editors will be glad to receive, for the purpose of making tliis 

 reoord^inore complete, copies of separate memoirs or reprints from periodicals, 

 whicli must otherwise often escape notice. 



