Anatomical Characters of the Human Brain. 15 



All of my figures are given in the table at the end of this article 

 and their bearing upon the percentage of the frontal lobe is given 

 in the two charts. In the first chart, Fig. 2, the weight of each 

 hemisphere is treated by itself and the weights are all reduced to 

 their weight in the fresh state. Of course, only those brains in 

 which the weight when fresh is known could be included in this 

 chart. In making the chart the weights of the frontal lobe are given 

 in ordinates and those of the rest of the hemisphere in abscissae. 

 Thus each symbol gives an individual haK brain. The diagonal 

 lines give the percentage of the frontal lobes and the diagonal lines 

 at right angles to them the weight of the hemi-cerebra. The symbols 

 in the first block and to the left represent hemi-cerebra, between 

 400 and 500 grams, the next block between 500 and 600 grams, etc. 



It is noticed that the weights of the hemicerebra range from less 

 than 400 to over 700 grams and that the percentage of the frontal 

 lobes fluctuates from 38 per cent to 49 per cent. The mean is about 

 43.5 per cent. If in each block the black and the white, and the 

 male and the female are compared it is seen that the distribution 

 is quite even and that on an average the percentage of the frontal 

 lobe is the same in both races and sexes. 



In order to give the question another and possibly a better test, 

 I tabulated all the brains in which both halves were weighed, but did 

 not reduce the figures to those of the fresh weight, for in a number 

 of specimens this is not given. Then the combined weight of both 

 sides was divided by two, thus giving the average weight of the 

 frontal lobe of each brain and that of each hemicerebrum behind 

 the central sulcus. In this chart, Fig. 3, each symbol represents a 

 whole cerebrum divided by two, and in it more of the symbols are 

 shifted to the left, for in general there is more shrinkage of the brains 

 due to the long action of formalin and carbolic acid. The individual 

 deviations are not as great as they are in Fig. 2 (39 per cent to 48 

 per cent) but the mean is about the same (43.5 per cent). Again 

 there is no separation of the brains due to race or sex. 



I must therefore conclude that with the methods at our disposal 

 it is impossible to detect a relative difference in the weight or size 

 of the frontal lobe due to either race or sex, and that probably none 



