KEFRACTIOX IN THE EYE 4., 7 



IX 



REFRACTION IN THE EYE 



The Eye as a Camera Obscura. 1. From the 

 eye of an ox remove the posterior part of the 

 sclerotic and choroid coats over an area about 

 1 cm. in diameter near the outer (temporal) side 

 of the optic nerve. Cover the retina with a watch 

 glass. Turn the cornea towards an incandescent 

 lamp. 



A small, real, inverted image of the lamp 

 will be seen upon the transparent retina. In the 

 white rabbit the choroid has so little pigment that 

 the retinal image may be seen without removing 

 the outer coats of the eye. 



2. In a darkened room, direct a blond, blue- 

 eyed individual to turn the eyes so that one 

 cornea shall lie in the outer angle of the eye. 

 Hold a candle near the temporal side of that 

 eye. 



The small, inverted retinal image of the 

 candle can often be seen shining through the 

 sclerotic coat at the nasal side of the eye. 



