Page:Popular Science Monthly Volume 27.djvu/88

76 has succeeded in completely changing my views on cerebral localization."

After the dog there was the monkey. Professor Ferrier introduced him. He had lost the motor zone in the left hemisphere seven months previously. Of him Professor Ferrier said: "As to any independent volitional action of the right arm and leg we have not seen a single indication since the operation was made. The animal is, in every other respect, perfectly well, and as to its tactile sensibility there is not the slightest sign of impairment." It is pleasing to know that, as the dog had been faithful to his master, so the monkey was true to his friend; he displayed the proper amount of paralysis on the opposite side of the body. In this connection Dr. Ireland's words are suggested. He says, "It is to be hoped, in the interest of the martyrs of cerebral physiology, that definite results will be attained as quickly and with as little suffering as possible."

Whatever may or may not be accomplished in finding definite centers of the brain for special movements and sensations, one thing stands fast—the cerebral hemispheres are the sole organs of the higher intellectual manifestations. From the time of Flourens, experiment has again and again shown that complete removal of the hemispheres is followed by stupor. All that resembles intellect disappears—spontaneous volition is gone. The animal remains buried in the profoundest repose. He originates no action. A low form of sensation and a low form of volition may remain. The animal when pinched gives evidence of pain; when set in motion, continues the motion till stopped by external hindrances. A frog deprived of the cerebrum and thrown into the water will swim until land is reached; a pigeon thrown into the air will fly until stopped by an obstacle or by exhaustion. It is to be particularly observed that the motions of these animals are strictly normal, i. e., pure motions; they are no longer connected with the higher power that once controlled them. They continue because they must continue.

A writer in the "Journal of Anatomy," of Paris, 1870-'71, gives a clear account of this matter. He says: "As a summary, alike in the inferior and superior animals, the removal of the hemispheres does not cause to disappear any of the movements that previously existed, but these movements assume certain peculiar characters. They are regular, for no psychical influence intervenes to modify them. They take place inevitably after excitation. The physiologist can, at will, in an animal deprived of the brain, determine such and such an act, limit it, arrest it. He can predict all the movements that will take place as certainly as a chemist knows in advance the reaction he will obtain from mixing certain bodies.

Pathology confirms our conclusion respecting these higher functions of the cerebrum. Loss of cerebral substance, in man, is followed by a weakening of the intellectual powers. They make a very childish