TIIRE.\D-CELLS AND KPl D KRM IS OF >1YXINE. 361 



nary epidermic cells. After staining with picrocarmine, it 

 is easy to trace the development of the thread cells, because 

 as the yellow-staining material is deposited in the cell the 

 red tint gives place to a yellowish red, and then becomes 

 altogether replaced by yellow, except the nucleus and a 

 small zone of granular matter around it, which retains its 

 pink tint. As the deposition of the yellow matter pro- 

 gresses striae make their appearance, which indicate the 

 commencement of the thread-like arrangement that obtains 

 in the mature cells (fig. 9). 



It seems a matter for surprise that these curious cells 

 should have hitherto escaped description, but as far as I am 

 aware there is only one drawing of them, which occurs in 

 Leydig's ' Manual of Histology ' (French translation, p. 225), 

 in which they are figured with threads appended to their 

 tails and described as nerve cells, the thread being regarded 

 as the fine termination of a nerve. 



The second kind of cell, the " spider cell,'' would appear 

 to represent the granular cells (Foettinger) of the epidermis, 

 which, when enclosed in the glands, undergo a process 

 whereby they lose their contents, and nothing is left save 

 the membrane and nucleus, and a granular material round 

 the latter. It may be that these cells are concerned in the 

 nourishment of the thread cells, or, as seems more probable, 

 they themselves contribute a constituent of the secretion, .^ 



probably the more liquid part. When in the gland they form / 



a sort of weak stfoma, holding together the thread cells. 



