FIG. 15.—Schematic transverse section of the human brain showing the projection of the motor
fibers, their crossing in the neighborhood of the medulla, and their termination in the different
areas of localized function in the cortex. S, fissure of Sylvius; M, the medulla; VII, the roots of
the facial nerves.An illustration of the effects of the lack of sensory stimuli on the cortex is well
shown in the case of Laura Bridgman, whose brain was studied by Professor
Donaldson after her death. Laura Bridgman was born a normal child, and
developed as other children do up to the age of nearly three years. At this time,
through an attack of scarlet fever, she lost her hearing completely and also the
sight of her left eye. Her right eye was so badly affected that she could see but
little; and it, too, became entirely blind when she was eight. She lived in this
condition until she was sixty years old, when she died. Professor Donaldson
submitted the cortex of her brain to a most careful examination, also comparing
the corresponding areas on the two hemispheres with each other. He found that
as a whole the cortex was thinner than in the case of normal individuals. He
found also that the cortical area connected with the left eye—namely, the right
occipital region—was much thinner than that for the right eye, which had
retained its sight longer than the other. He says: "It is interesting to notice that
those parts of the cortex which, according to the current view, were associated