EPENDYMA OF THE VENTRICLES OF THE BRAIN. 



313 



instance a separation of a rough kind may certainly not 

 unfrequently be effected, but a more delicate kind of 

 separation is altogether impossible. When the surface of 

 any section of the ventricular wall is examined with a 

 tolerably high power, the first thing noticed on the sur- 

 face is an epithelium, sometimes in a better, sometimes 

 in a worse state of preservation (Fig. 94, E). In the 

 most favourable cases we find cylindrical epithelium with 

 cilia, extending throughout the whole extent of the 

 cavity of the spinal marrow (central canal) and of that 

 of the brain (ventricles). Beneath this layer follows a 

 sometimes more, sometimes less pure layer of a structure 

 resembling connective tissue, which at first sight cer- 

 tainly appears to be separated by a sharp outline from 



FIG. 94. 



^ &Q. 



^4?^, ' 

 *s^^^:^ I 



Fig. 94. Ependyma ventriculorum and neuro-glia from the floor of the fourth 

 cerebral ventricle. E, Epithelium, N y nerve-fibres. Between them the free portion 

 of the neuro-glia with numerous connective-tissue-corpuscles and nuclei, at v a ves- 

 sel. In addition, numerous corpora amylacea, which are moreover represented 

 separately at ca. 300 diameters. 



