

Wft 



§ 





(;r: 





(••^: 





■'^) 





(2^ 



a 



;^y ^ 



% 



a':« 



<2/ 



B 



Fig. 9. 



A — Undeveloped ganglia cells in the optic lobe of a dog, the eyes of which have been 



sewn up immediately after birth. B— Fully developed ganglia cells in the same 



region of a normal dog of the same age. (After Berger.) 



