STUDIES ON CILIATED CELLS 267 



hypothesis are: (a) the shape and position of basal corpuscles in 

 the ciliated cell correspond with those of the centrosome in 

 neighboring non-ciliated cells (Lenhossek, Holmgren) ; (6) viewed 

 in unstained preparations, the basal corpuscle refracts light as 

 strongly as does the centrosome (Lenhossek) ; (c) both the above 

 structures show stain in the same way (Lenhossek) ; (d) the cili- 

 ated cell lacks centrosomes (Lenhossek, Fiisst, Fuchs, Jordan); 

 (e) the ciliated cell bears resemblance either to a spermatid 

 (Henneguy, Lenhossek) or to a ' Zentralgeisselzelle' (Joseph) ; (/) 

 no mitotic figure is seen in the ciliated cell, because the latter 

 lacks centrosomes (Henneguy, Lenhossek, Fuchs, Joseph) ; (g) the 

 basal corpuscles arise from the centrosome. 



There are many other investigators whose opinions are ad- 

 verse to the above hypothesis ; they bring forward the following 

 facts in support of their view ; (a) the granules which stain black 

 with iron-haematoxylin cannot always be said to be centro- 

 somes, for there are many other cell-constituents which give the 

 same reaction (Studnicka '99, Fischer '99) ; (6) contrary to the 

 view of Lenhossek, the centrosome is often situated deeply; (c) it 

 can scarcely be said that the ciliated cell lacks centrosomes when 

 it is not met with (Merkel '08) ; {d) the ciliated cell has a centro- 

 some (Studnicka '99, Eismond '00, Fischel '00, Henry '00, Gur- 

 witsch '00, Wallengren '05, Erhard '10, Tschassownikow '13); 

 (e) sometimes mitosis is observed in ciliated cells (Gurwitsch 

 '00, '01, Maier '03, Wallengren '05, Erhard '10, Gutheil '11); 

 (/) the basal corpuscles are not derived from the centrosome, but 

 from other cell-constituents (Gurwitsch '00, '01, Wallengren 

 '05, Erhard '10, Gutheil '11). 



My observations also are not in accordance with the hypothe- 

 sis of Henneguy and Lenhossek; they are summarized as follows: 



1. The basal corpuscle refracts light strongly and stains 

 deeply with iron-haematoxylin, but these properties are not 

 characteristic of these bodies. 



2. I have found centrosomes in many ciliated cells. 



3. The existence of the centrosome does not always signify 

 the occurrence of mitosis, for the ciliated cells of vertebrates do 

 not multiply by mitosis, though they contain distinct centro- 

 somes. 



