Page:Popular Science Monthly Volume 27.djvu/85

Rh on the left hemisphere. He bandaged the left eye, and allowed the animal to recover from the chloroform. "Upon recovery it began to grope about a little in loco, perfectly alert, but would not move from its position; hearing and the other senses were not affected, for there was always a prompt reply to stimulation of these senses." The animal remained in this position for an hour. The bandage was then removed from the left eye. "It instantly looked around, ran quickly to the cage and joined its companions. When brought to the light, as before, it flinched and turned away its head." Ferrier describes the change in the animal's manner, after removal of the bandage, as most complete and remarkable. On the following day the left eye was again bandaged, but "the animal gave plain signs of vision, it ran swiftly and accurately to the bars of the cage, thrust its head between them, and began to drink from a cup of water." In his next experiment Ferrier destroyed the angular gyrus on both hemispheres. He found great difficulty in forming a right test for vision, one which should discriminate between sight as a state of consciousness and simple reflex reaction to visual stimulation.

The animal sat perfectly still and would not move from its position. "The pupils contracted to light, and light flashed in the eyes caused the animal to wince." It was utterly unwilling to move from its place; nothing else showed lack of vision. Ferrier's test was a cup of tea, which the animal liked very much. Ferrier placed the tea to the monkey's lips; it began at once to drink eagerly. The cup was then removed, but barely removed, from contact with the lips. "The monkey seemed intensely anxious to drink, but could not find the tea, though both eyes were looking straight at it." As soon as contact was established, the monkey buried his head in the cup and followed it around the room, as the cup was slowly lowered.

Munk's experiments on vision led him to different results. He removed the entire angular gyrus from the left hemisphere; he then raised the lids of the left eye with his fingers and touched parts of the eye softly; immediately there were blinking and vigorous movement of the head and muscles of the eye. The animal made every effort to draw back its head, and almost always accompanied these efforts by striking with the left front-limb. With the right eye, however, the case was entirely different. This eye could be pressed and pinched constantly, and the animal remained perfectly quiet.

If the finger or hand was brought suddenly up close to the left eye there was blinking; if to the right eye, no blinking at all resulted, unless the lids were actually touched. Munk removed the center, marked O, Fig. 1, from the occipital lobe in both hemispheres. He says: "In from three to five days after the operation there was nothing abnormal in the hearing, smell, taste, movements, or sensations of the animal, only in the territory of sight was there any peculiar disturbance. The animal moved about the room or garden with perfect