2 ELEMENTS OF APPLIED MICROSCOPY. 
as corresponding to a definite object perceived by the 
other senses. The image is in all cases inverted, but in 
infancy it is found that images upside down correspond 
to objects which are really right side up. Experience 
Fic. 1.—SECTION THROUGH THE HuMAN EVE. 
(After Everett-Deschanel.) 
A. Cornea. - Retina. 
B. Aqueous humor. Vitreous humor. 
C. Pupil. i Optic nerve. 
D. Iris. N. Inferior rectus muscle. 
E. Lens. O. Superior 
- yeaa) ligament. i ra jLevator palpebre muscle. 
. Accommodation muscle. : . . 
H. Sclerotic coat. R. ¢ Meibomian glands. 
ZI. Choroid coat. 
teaches, also, that an image of a certain size produced 
by an object at a given distance always implies a 
definite magnitude; and we are therefore able to judge 
something about the actual size of an object from the 
size of its image and our knowledge of its remoteness. 
