Histology. — ".4 Contribution to the Histophysiology o f the Ciliated 

 Epithelium''. Bj Dr. M. W. Wokhdkman. (Communicated bv 



Prof. G. VAN RlJNBERK). 



(Communicated at the meeting of September 29, 1923). 



The sudden reversion of the direction of the ciliary movement 

 which we linow to be a property of a number of protozoa, is of 

 very rare occurrence in metazoa (literature Erhard '). As tar as I 

 know it lias liitherto not been found in ciliated ceils of amphibians. 



V. Bkijcke ') hit upon the idea of detaching small patches of the 

 oral mucous membrane in frogs and allowing them to coalesce again 

 after having turned them 180°. These experiments were hampered 

 by all sorts of diilliculties, such as inflammation, necrosis of the 

 patclies, suppuration etc. Macroscopically it could be observed in 

 two animals that the epithelium of the patch was not destroyed, so 

 that v. Bhückk was alile to study the direction of their ciliary 

 movement for 40 days. The cells continued acting in the original 

 direction. 



In tiiree other animals the epithelium of the patch was most likely 

 (v. Brücke did not examine it microscopically) displaced by epithe- 

 lium that arose from the borders of the wound. This regenerated 

 epithelium exhibited a normal direction of the ciliary movement. 

 Experiments made l)y Merton *) in the past year substantiate v. 

 Brückk's data, so thai it seems quite certain that in adult frogs it 

 is not possible to reverse the direction of the ciliary movement, i.e. 

 to alter the polarity of the ciliated cell. 



Indeed, the negative results of Schöne's *) and of Weigel's *) 

 experiments with other epilhelia had already made us suspect this; 

 but. then, it was exactly in ciliated epithelium that the direction 



') Erhard in Abderlialden's Handb. d. bid. Arbeitsmethoden. 



') E. Th V Brücke. Pflüger's Arch. f. d. ges. Phys. Bnd. 166. 1917. 



3) H. Mekton. Pflüger's Arch. f. d. ^es, Pbys. Bnd. 198. 1923. 



*» Schone Die lieteioplKstische and liomüioplastische Transplantation. Berlin 1912. 



») Weigel. Arch, f Entw. mechan. der Organismen. Bnd. 36. 1913. 



