398 PROCEEDINGS OF THE CANADIAN INSTITUTE 



of the cell on its free surface is due to the reagents employed. Ebstein 1 ' 

 found both closed and open cells, the latter form arising from the first 

 through the transformation of their contents into mucous. Bieder- 

 mann 2 found the cells always open and the mouth of each containing 

 a plug which is chemically and morphologically different from the 

 remainder of the cell. The stopper shows a longitudinal stria tion. 

 Eeg^czy 3 regarded these cells as ciliated., having found cilia on them 

 in the frog and in some fishes, frequently on a portion of the peri- 

 pheral membrane. In some cases the cilia were cemented in on© 

 mass at the end of the cell, and in others, again, he observed the 

 absence of these cilia apparently through their withdrawal into the- 

 cell. They are very easily destroyed by chemical reagents, which 

 cause also a swelling up of the contents of the cell. 



The many different views of the structure of these cells are no 

 doubt due to observing epithelium prepared in a manner which 

 changes more or less its normal appearance. Alcohol, Midler's fluid, 

 solutions of potassic bichromate, and ammonia bichromate, cause a 

 swelling up and an emptying of the contents of the cell in its outer 

 third. When examined in the fresh state all cells have the arched, 

 glancing border, apparently due to the meeting of two fluids of dif- 

 ferent consistency. The contents are similar throughout the cell,, 

 and finely granuled. Owing to the action of the reagents mentioned 

 the outer two-thirds of the cell becomes clear and glassy, and the 

 arched border is absent. When a specimen is hardened in osmic 

 acid, on the other hand, the arched border is preserved, the outer 

 third of the cell contents is somewhat more coarsely granuled, and 

 more darkly stained than the remainder, the. latter effect not by any 

 means due to the greater ease with which the acid attains to that 

 portion of the cell. Rarely did the use of this reagent betray the 

 absence of the arched border or the apparent presence of a peripheral 

 cell-wall. At the same time the division of its contents into muci- 

 gen and protoplasm not coinciding with that shown by other reagents 

 was a constant one throughout. A structure closing the mouth of 

 the cell and answering to Biedermann's ' plug,' has never been, 

 observed by me in the stomachs of the many fishes which I have 

 studied. 



i Archiv fur Mikr. Anat. Bd. VI., page 519. 



2 Wiener Akad. Sitzungberichte LXX., Bd. III., s. 377. 



a Archiv fur Mikr. Anat. Bd. XVIII., page 408. 



