105 



not iue to variation in the action of reai?,ents, for I have 

 several instances showing the marked contrast in one and the 

 saoie section. A structural difference here is a noteworthy 

 fact, since the tv»o neurones are both of the somatic motor 

 type, entirely equivalent morphologically. 



5. The Epenit^ma. 



The general character of the ependynoa of the midbrain is 

 represented in Pig.?l, ep. , while Pig. 61 illustrates the de- 

 tails of cell-organization. The outline of a representative 

 cell is somewhat lance-like, tne length four times the breadth, 

 the pointed extremity touching the ventricle and the greatest 

 breadth at a point further removed. The interior of the cell 

 is occupied almost entirely by the nucleus. It is really dif- 

 ficult to detect any cytoplasm at all except in a small area 

 at the base of the ependymal fibre. The observer has the im- 

 pression forced upon him that most of the cytoplasm during 

 the course of growth has passed over into the cell-process. 

 The strjcture of the nucleus is reticulated to an almost ex- 

 treme degree. Some strands of the reticulirn are relatively 

 coarse, but many of them are so tenuous as to lie almost beyond 

 the capacity of the microscope. 



Tne ependymal fibre takes a course which is almost straight 

 during the first part of its length, but toward the outer limit 

 of the central gray matter crooked turns occur, and branches 



