STUDIES ON CILIATED CELLS 247 



('04), results from the disappearance of the rootlets of the ciUa 

 on account of the accumulation of secreted material ; concerning 

 this he writes as follows: "La destruction du cone radiculaire 

 deLruit les communication, quelle qu'en soit la nature, du cyto- 

 plasme et des cils. Isoles, ceux-ci ne peuvent plus que degenerer 

 et disparaitre." 



The transformation of ciliated cells into columnar has been 

 observed by Henry ('00) in the epididymis, and by Gurwitsch 

 ('00) in the intestine and the mouth of Lumbricus. 



Observations 



1 . The hepatic duct of Helix. The epithelium from this struc- 

 ture consists of ciliated, non-cihated columnar, and glandular 

 cells. The ciliated cells become converted into non-ciliated 

 columnar and the latter into glandular. This process can eas- 

 ily be followed in one and the same section. First, minute 

 granules, stained yellowish by iron-haematoxylin, make their 

 appearance above the nucleus (fig. 11, the cell to the left); they 

 then increase in size and number and pass gradually upwards. 

 Next, the ciha and the basal corpuscles disappear (fig, 11, the 

 cell to the right) ; it seems that the cilia are not withdrawn, but 

 are cast off in one of two ways: (a) they are broken off at the 

 junction with the cell; the broken fragments are, in fact, met 

 with in large number in the lumen; (6) they curl up and become 

 converted into small drops, which at first are applied to the 

 surface of the cell, but afterwards are separated from it. Thus 

 the ciliated cells are turned into non-cihated columnar, and 

 after the discharge of secreting mass into goblet cells. 



2. The intestines of Anodonta and Lumbricus. The epithelium 

 from these organs is composed of the same kinds of cells as 

 those found in the hepatic duct of Helix. In many of the non- 

 cihated columnar cells there can be seen a row of basal corpuscles 

 and a transparent zone, just as in the ciliated cells. On ob- 

 serving closely the cuticle of such cells, we often find some cilia 

 (fig. 8) which are, as usual, connected with the basal corpuscles. 

 Such cells might be interpreted as a form of transition between 



