THE CEREBRAL HEMISPHERES. 315 



history of the vague speculations of the ancients or the fruit- 

 less experiments of modern observers. It is to be hoped that 

 future anatomical investigations, chiefly in following out 

 the course of the fibres of the encephalon and their connec- 

 tions with the cells of the different collections of gray mat- 

 ter, will throw light upon the functions of this part of the 

 cerebro-spinal axis; but at present, all physiologists will 

 admit that we have received very little aid from this 

 source. In our anatomical descriptions, therefore, we shall 

 confine ourselves to those points that are strictly physio- 

 logical. 



Weight of different Parts of the Brain and of the entire 

 Encephalon. Most of the tables of the weight of the healthy 

 adult brain of the Caucasian, given by different observers, 

 show essentially the same results, the differences amounting 

 to only one or two ounces for the entire encephalon. The 

 average given by Quain is 49J ounces, avoirdupois, for the 

 male, and 44 ounces for the female. This is the general re- 

 sult obtained by combining the tables published by Sims, 

 Clendinning, Tiedemann, and Reid. The number of male 

 brains weighed was 278, and of female brains, 191. In 

 males, the minimum weight was 34: ounces, and the maxi- 

 mum, 65 ounces. In 170 cases but of the 278, the weight 

 ranged from 46 to 53 ounces, which may be taken as the 

 general average. In females, the minimum was 31 ounces, 

 and the maximum, 56 ounces. In 125 cases out of the 191, 

 the weight ranged from 4:1 to 47 ounces. 



Quain assumes, from various researches,, that in new- 

 born infants, the brain weighs 11 '65 ounces, for the male, 

 and 10 ounces, for the female. In both sexes, " the weight 

 of the brain generally increases rapidly up to the seventh 

 year, then more slowly to between sixteen and twenty, and 

 again more slowly to between thirty-one and forty, at which 

 time it reaches its maximum point. Beyond that period, 

 there appears a slow, but progressive diminution in weight 



