According to him, the weight of the brain has no in~ue.nce whatever on. the mental faculties. It ought to b& remembered that the slgmficance of the weight of the brain should depend upon the proportion it bears to the dimensions of the whole body and to the age of the individual. It is equally important to know what was the cause of death, for long illness or old age exhausts the brain. To define the real degree of development of the brain it is therefore necessary to have a knowledge of the condition of the whole body, and, as this is usually lacking, the mere record of weight possesses little significance.
The human brain is heavier than that of all the lower animals, excepting the elephant and whale. The brain of the former weighs from eight to ten pounds; and that of a whale, in a specimen seventy-five feet long, weighed rather more than five pounds.
Cerebral Localization and Topography.-Physiological and pathological research have now gone far to prove that the surface of the brain may be mapped out into series of definite areas, each one of which is intimatelv connected with some well-defined function. And this is especially true with reeard to the convolutions on either side of the fissure of Rolando, which are believed by most pbysiolozists of the present day to be concerned in motion, those grouped around the fissure being associated with movements of the extremities of the opposite side of the body, and those around the lower end of the fissure being related to movements of the mouth and tongue
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