VISION. 



527 



sion of at least some of the laws of the science of optics. The 

 student is, therefore, recommended to leam practically the 



SUPERIOR RECTUS 



CHOROID 



PTIC NERVE 



», FiQ. 376.— Section of human eye, somewhat diagrammatic (after Hint) 



coarse and microscopic structure of the eye in detail. The eyes 

 of mammals are sufficiently alike to make the dissection of any 

 of them profitable. Bullocks' eyes are readily obtainable, and 

 from their large size may be used to advantage. We recom- 

 mend one to be boiled hard, another to be frozen, and sections 

 in different meridians to be made, especially one axial vertical 

 longitudinal section. Other specimens may be dissected with 

 and without the use of water. 



Assuming that some such work has been done, and that the 

 student has become quite familiar with the general structure 

 of the eye, we call attention specially to the strength of the 

 sclerotic coat; the great vascularity of the choroid coat and its 

 terminal ciliary processes, its pigmented character adapting it 

 for the absorption of light ; the complicated structure and pro- 

 tected position of the retinal expansion. It may be said that 



