FIG. 376. 



352 NORMAL HISTOLOGY. 



fibres of Miiller, which extend through the entire thickness of 

 the retina. The expanded inner ends of the supporting fibres are 



so closely applied 

 that they produce a 

 seemingly continu- 

 ous membrane, the 

 so-called mem- 

 brana limitans 

 interna, which for 

 a long time was de- 

 scribed as a special 

 layer of the retina. 

 The radial fibres 

 rapidly diminish in 

 diameter beyond 

 their bases, and pass 

 through the outer 

 part of the ganglion- 

 layer and the inter- 

 nal reticular layer as 

 narrow stalks, giving 

 off few, if any, lat- 

 eral branches in their 

 transit as far as the 

 inner nuclear layer. 

 On arriving at this 

 plane each fibre pre- 

 sents an irregular 

 nucleated enlarge- 

 ment, and gives off 

 lateral processes for 

 the support of the 

 elements of the inner 

 nuclear layer, as well 

 as to each of the succeeding layers. At the inner border of the rods 

 and the cones the expanded ends of the neuroglia-fibres form the ex- 

 ternal limiting membrane, delicate processes extending from the 

 latter between the bases of the rods and the cones, which they sur- 

 round and embrace as the " fibre -crates." In addition to the long 

 radial fibres, richly-branched neuroglia-cells occur within the outer 

 reticular layer to the fibre-complex of which they contribute. 



Within the meshes of the framework just described the nervous 

 elements of the retina are distributed in a manner characteristic for 

 each layer : a brief consideration of these is therefore necessary. 



Diagram of relation of retinal elements ; the left portion of the 

 figure represents the supporting neuroglia-fibres, the right portion 

 the principal nervous constituents : a, internal limiting membrane ; 

 , fibre-layer; c, layer of ganglion- cells ; d, inner reticular layer ; e, 

 inner nuclear layer ; _/) outer reticular layer ; g, outer nuclear layer 

 Jt, external limiting membrane ; i, layer of rods and cones ; k, ex 

 panded bases of Miiller's fibres ; m, enlargement containing nuclei 

 n, projections between bodies of visual cells (/) ; o, fibres extend 

 ing between rods and cones (r, s) ; t, nerve-cells of inner nuclear 

 layer ; x, y, assumed but questionable connections. (Modified from 

 Stohr.) 



