AND PERSONALITY 



mechanism of locomotion as man. Evolution conferred 

 survival value upon the mechanism of balancing and the 

 upright posture, because it released the forelegs to become 

 the priceless heritage possessed by no other animal, namely, 

 the manipulative hand. In its ceaseless activity the manip- 

 ulative hand required the evolution of brain cells and a 

 corresponding evolution of action patterns in the white 

 matter. No lower animal possesses a comparable mechanism 

 in the gray matter or in the white matter. However, the 

 upright posture and the manipulative hand could have 

 little survival value without the collaboration of the 

 eye. 



The retina of the eye is a specialized part of the brain, 

 projected through a hole in the skull, whose rods and cones, 

 or antennae, are exposed directly to light. In the retina of 

 the eye there are about a hundred million individual 

 photoelectric cells, each one of which communicates with 

 one or more of the hundreds of millions of brain cells that 

 constitute the mechanism of seeing. 



The vital role of the eye, in thinking, reading, walking, 

 and working, is indicated by the great number of diseases 

 of the eye found in civilized man. With its millions of units 

 of energy and its infinite numbers of communications to 

 every other part of the brain, the eye has conferred great 

 survival value upon man himself. 



Through the eye man has been made aware of the dis- 

 tance of one object from another. This physical fact alone 

 has great survival value. Through the eye man has also 

 been made aware of all the colors of the rainbow. Through 

 the eye the brain of man has been made aware of the dis- 

 tance and contour of objects, of the speed of movement, and 

 of the ground about him. The eye is the most important 

 sense organ. With it man sees the written page and through 

 the written page secures his education. 



The upright posture with its vast mechanism and the 

 manipulative hand with its vast mechanism owe their 



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