Date of Award


Document Type


Degree Name

Master of Arts (MA)



First Advisor

Calude E. Thompson


The retina of the human eye is made up of ten layers. One of these layers, the bacillary layer, is composed of 130 million rods and 7 million cones.(1) It would appear, in view of the unusually large proportion of rods to cones, that the rods were of much greater importance to the process of seeing than the cones,-— but this is not the case at all. The cones, it is true, are very thinly scattered throughout the peripheral area of the retina; so thinly scattered, in fact, as to appear almost entirely lacking. The proportion of cones increases, however, as the visual axis is approached. They become the exclusive element of the macula, that localized area directly in line with the visual axis.(2) Thus, the focal point of vision, plus a reasonable area of the retina surrounding it, is almost exclusively made up of cones. Are the cones, i.e., the agents of color vision, important to visual perception? They certainly are. They are, by far, the most influential factor in the process of seeing.

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