XVIII. 

 THE EYE AND VISION. 



A. The Eye of an Ox. 



Materials. The eye of an ox may be easily obtained at the mar- 

 ket. Care should be taken to obtain a fresh specimen. Potassium 

 bichromate, 1 per cent solution. 



Apparatus. A small glass jar. 



THE PARTS OF THE EYE. 



a. The muscles on the outside of the eye. 



1. How many do you find ? 



2. Where are they attached? 



3. What is the use of each ? 



b. Do you find anything else on the outside of the eye ? 

 What is its function ? 



c. Remove the muscles and fat and find the optic nerve. 



1. Is it in the axis of the eye ? 



2. Can you determine whether your specimen is 



the right or the left eye? 



d. Sketch a front and a side view. 



e. The cornea is the transparent coat on the front of the 

 eye. 



/. The sclerotic coat is the white or gray opaque coat 

 that is continuous with the cornea. The cornea and the 

 sclerotic coat form the outer covering of the eye. 



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