366 



PRACTICAL HISTOLOGY. 



[xxxii 



microscope the coloration of the nervous elements, especially the 

 cells in the retina. Mount in picrate of ammonia and glycerine (p. 

 192). 



11. V.S. Retina. (L) Beginning from within, i.e., next the 

 vitreous, observe (fig. 341) 



(a.) The internal limiting membrane, 

 and springing from it by wing-shaped 

 expansions the fibres of Miiller, which 

 run vertically outwards through the 

 layers of the retina to the outer limiting 

 membrane. 



(b.) The fibrous layer, composed of 

 the non-medullated fibres of the optic 

 nerve. The fibres are medullated in the 

 optic nerve, but they lose their medulla 

 as they enter the retina. The layer is 

 thinner in the anterior part of the 

 retina. Some of the nerve-fibres end 

 in the ganglionic cells of the next layer, 

 but others pass outwards to the inner 

 molecular layer to end by terminal 

 arborisations there (shown by Golgi's 

 method). 



(v.) The ganglionic or nerve-cell 

 layer, consisting of a single row of large 

 multipolar nerve-cells, each cell with a 

 large conspicuous nucleus. Each cell 

 gi vos on? (i-) one thick process, which 



is and cones; le, li. Exter- may divide into several processes which 

 ' pass towards and ramify by terminal 



pb Basal plexus ; cb. Bipolar arborisations in the layer external to this, 



cells; CM. Unipolar cells ; bi. ... . J . 



Internal basal cells ; pc. Cere- and (ll.) OI1C 11116 axis-Cylinder process 



towards the optic nerve -fibre layer, 

 where it becomes continuous with a 

 nerve-fibre. Between the nerve-cells, or 

 in close relation to them, sections of the 

 ami'granular layers; C. Cellular larger blood-vessels. 



layer; ^.Fibrous layer. (d.)The internal molecular layer 



appears to consist of fine fibrils or 



granules. It is not unlike the grey matrix of the cerebrum, and is 

 traversed by the fibres of Miiller and also by fibres of the optic nerve, 

 and processes of the cells of the ganglionic and inner granular layers* 



(e.) The internal nuclear layer,- deeply stained, and consisting 

 of several rows of large spherical oval nuclei. 



Some of the granules, however, by other methods can be shown 



FIG. 



bral plexus ; 

 nerve-cells ; fo. Fibres of optic 

 nerve. On.the left the initials 

 of the usual names for these 

 layers ; R C. Rods and cones ; 

 EN., EG., and IN., IG. Ex- 

 ternal and internal nuclear 



