SENSE OF VISION. 



[Fig. 44. 



243 



"'- -tf 



A Horizontal Section of the Eye-Ball; 1, sclerotic coat; 2, sheath of the optic nerve, or canal of Fon- 

 tana; 3, circular venous sinns of the iris; 4, proper substance of the cornea; 5, arachnoidea oculi; 6, 

 membrane of the anterior chamber of the aqueous humour; of the two dotted lines one points to the sup- 



