INCREASE OF THE BRAIN IN WEIGHT. I I J 



have pointed out that among all the geographical 

 groups, except the European and the Australian, there 

 are two types of brain, a. light and a heavy, these two 

 types being well marked in the Oceanic, Asiatic, and 

 African races, though the average figures here, given do 

 not take account of them. 



The extreme difference shown in this table between 

 the. average weights for the males is (European, 1,340 ; 

 1,190, Australian) 150 grammes, while the European 

 female is 160 grammes, less than the male ; thus putting 

 the Australian male and European female on the same 

 level as regards gross brain-weight, and thereby suggest- 

 ing that the inference from brain-weight directly to 

 intelligence is not a happy one. There are several 

 circumstances which here influence the determination 

 of the difference between the sexes. On the one hand, 

 in grouping skulls according to sex by means of osteo- 

 logical characters, those male skulls which have the 

 special characters poorly developed are placed in the 

 female group, and vice versa. Since capacity is not 

 dependent on these characters, the result of this is to 

 put some larger male skulls in the female group, and 

 vice versa, and so to make more equal the figures for 

 the two sexes. At the same time, Davis assumed that 

 the relation between the weight of the brain and the 

 capacity of the skull was the same for both sexes. 

 From the observations of Bischoff, 1 there is reason to 

 think that in the female the brain more nearly fills the 

 cranial cavity by from 3 to 4 per cent. Introducing 

 this correction into the table would alter the result 

 materially by raising the average weight for the 

 female. But, granting all corrections, the most striking 

 feature of the table, the high average brain-weight of 

 the European male, would not be materially affected, 

 1 Bischoff, Hirngewicht des Menschen, i?8o. 



