252 S. SAGUCHI 



far from a satisfactory solution. From tlue well-known fact 

 that the centrosomg directs mitosis in general, it must be ad- 

 mitted that the mitosis of a cihated cell is also in close relation 

 to the existence of the centrosome. 



The centrosome of the ciliated cell 



Upon this question, two distinct and opposed views are held 

 by histologists. Henneguy ('98), Lenhossek ('98), Zimmerman 

 ('98, in the uterus), Heidenhain ('99), Fuchs ('02, '04), Joseph 

 ('03, '04) and others say that cihated cells lack centrosomes; 

 many investigators (Studnicka '99, Fischel '00, Eismond '00, 

 Henry '00, Benda 'OO-'Ol, Gurwitsch '00, '01, Ach '02, Wallen- 

 gren '05, Ikeda '06, Erhard '10, and Tschassownikow '13), on 

 the contrary, believe that they have found centrosomes in 

 cihated cells. 



It is a difficult matter to find centrosomes with certainty; for 

 thej^ are minute corpuscles and often are apt to escape observa- 

 tion. Hence, it can hardly be said that they are absent when 

 they cannot be detected; on the other hand, there are many 

 other corpuscles which are similar to the centrosome in shape, 

 position, and staining reaction, but of a different nature. Wal- 

 lengren ('05) noticed such granules in ciliated cells, and said 

 that they must be passed out of the nucleus, and to be closely 

 related to the secreting process. We can only speak of centro- 

 somes where the corpuscles show constant shape position and, 

 staining powers and directly conduct mitotic division of the 

 cell. It is very difficult, though not impossible, to follow such 

 processes. Wallengren ('05) has already noticed that diplosome- 

 like granules which are present between the basal corpuscles 

 become centrosomes directing the karyokinetic cell-division. 



I have noticed what are to be regarded as centrosomes in the 

 following situations. Before describing my observations, it 

 must be remarked that the centrosomes, in my conception, are 

 to be recognized from the constancy of their shape, position and 

 staining reactions, and, that whether or not these corpuscles, in 

 reality, conduct the mitotic division, in other words, whether all 



