Anatomy, physiology and hygiene . e a defi-ciency of cerebral substance for that class of connections.— Bain, Mindand Body. 284 THE NERVOUS SYSTEM. faculties are of a complex nature, and are produced by acoalition of a number of impressions. The functions of the rounded masses near the base ofthe cerebrum, called basal ganglia, are not settled, owingto experimental difficulties. But the centres or areas of motion, sight, smell, and hear-ing are quite clearly motor areas, or thosewhich are associated with def-inite motions of the voluntarymuscles, are in the upper andside portion
Anatomy, physiology and hygiene . e a defi-ciency of cerebral substance for that class of connections.— Bain, Mindand Body. 284 THE NERVOUS SYSTEM. faculties are of a complex nature, and are produced by acoalition of a number of impressions. The functions of the rounded masses near the base ofthe cerebrum, called basal ganglia, are not settled, owingto experimental difficulties. But the centres or areas of motion, sight, smell, and hear-ing are quite clearly motor areas, or thosewhich are associated with def-inite motions of the voluntarymuscles, are in the upper andside portions of the cerebralcortex, and usually on theopposite side of the body fromthe muscles moved. The surgeon, by the removalof tumors or clots of bloodfrom certain motor areas, hasrelieved cases of epilepsy andparalysis. Studies of diseased conditions of the brainindicate that the removal of certain portions of the brain,respectively, or injury to them, will produce blindness,deafness, or lack of smell, etc., as the case may be. The. Fig. 91. Brain Localization. P, pons. M, medulla. CEE, cerebellum. 1 Investigations seem to show that the centres for motion, sensation,and the mental faculties are not so isolated as has been hitherto supposed,but that they are more diffused and shade off into each other. Thusa wonderful provision is made for emergencies. If the very heart of acentre or area be injured, there will be oftentimes sufficient nervous tissueremaining to perform the work in a more or less perfect manner. The faculty of articulate language appears to reside in the third orinferior frontal convolution of the left side, which convolution would con-tain both the centre for the memory of words, and the centre for the co-ordination or combination of the movements of speech.—Cooke,Tablets of Physiology. THE NERVOUS SYSTEM. 285 centres for sight are in the occipital lobes of the cerebrum;the centres for hearing, near and behind each ear; forsmell, on the sides of the cerebrum in
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