404 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



and is provided with the usual pore canals. Outside of the cell 

 walls, and of a diameter equal to that of the cell, are sometimes in 

 hardened sections small masses which show a striation parallel to 

 the pore canals. These are probably in all cases due to a destruction 

 of the excessively fine cilia which has been described by Thanhoffer 1 

 in the frog, and by Edinger 2 in the eel, pike, carp, &c, and observed 

 by myself in scrapings from the intestine of the living fish. I have 

 never succeeded in observing their movement. Edinger suggests 

 that they are in constant action during digestion. It is impossible 

 to verify this with certainty, as removal of the cell apparently causes 

 instantaneous death. . In this respect, as in their extraordinary 

 delicacy, they are comparable to the cilia of the cylinder cells mingled 

 with the olfactory cells of the nasal cavity of higher vertebrates. 



The beaker cells are quite different from those of the oesophagus, 

 and this difference corresponds to that between the ordinary cylinder 

 cells of the midgut and the oesophagus. In both cases the beaker 

 cells are not original structures, but are metamorphosed products of 

 cylinder cells. I might mention here that I observed in fresh ciliated 

 epithelium from the spiral valve of the sturgeon, several cases of 

 beaker cells still possessing a fringe of cilia. On the other hand the 

 effects of the drug pilocarpin teaches quite clearly the origin of the 

 beaker cells. After the peristaltic contractions caused by this drug 

 have passed away, beaker cells are found to be totally absent from 

 the surface of the intestine and Lieberkuhnian crypts, their place 

 being occupied by cylinder cells. A fresh supply is obtained in the 

 resting intestine, and these can only come from the cylinder cells. 



The theca of the beaker cell presents various shapes and sizes 

 graded from the cylinder cell. Sometimes a short portion of the 

 wall is swollen to form the theca ; the peripheral wall is lost and the 

 contents become very coarsely granular, the remainder of the con- 

 tents of the cell being unchanged. Further progress shows the 

 advance of the transformation nearer the nucleus, which, however, 

 it does not embrace ; at the same time the theca loses its swollen 

 character and becomes elongated. The opening may be as wide 

 or wider than the original cell, and through it frequently projects 

 a rounded mass of the swollen contents. 



The crypts of mucous surface are simply those of the pylorus in 



i Pluger's Archiv, Bd. VIII., p. 391. 2 Loc. cit. 



