2l6 



PHYSIOLOGY FOR BEGINNERS 



CHAP. 



The rod cells, which are the more numerous, and are closely 

 packed together, consist of a rod-like process directed out- 

 wards towards the choroid, and of a tapering thread-like pro- 



A B 



FIG. 101. Diagram of the nervous (A) and connective tissue elements (B) of the 



retina, supposed to be separated from one another. 



A. b, rods ; c, cones ; // and c f , nuclei of the rods and cones ; tf, fine interwoven 

 nervous filaments, from which fine filaments proceed, bearing the nuclei S, f \ 

 from these filaments (g) proceed to the nerve cells k, k ' ; i, fibres of optic nerve, 

 forming the innermost layer. 



B. a, external limiting membrane ; f>, internal limiting membrane ; e, connective 

 tissue fibres ; S, nuclei ; d and g, fine granular layers. 



cess, ill which lies a nucleus, passing inwards towards the 

 vitreous humour. The cones, which are interspersed among 

 the rods, are sugar-loaf in shape, with a short, outer process, 



