VARIATIONS IX BRAIN-WEIGHT. 133 



this point is warranted because the central nervous 

 system, whatever its natural perfection, must be ex- 

 tremely responsive to surrounding social conditions, and 

 thus growth processes in it be modifiable in no small 

 degree, hence the conditions which social status implies 

 are probably important. 



The group of very large brains yet remains to be 

 considered. The weight recorded for the brain of Oliver 

 Cromwell, 2,231 grammes; for Byron, 2,238 grammes; 

 and for Turgenieff, 2,012 grammes, would have given 

 these persons heads which could hardly have escaped 

 description or portraiture, by which the post-mortem 

 records might be corroborated. But there is a complete 

 absence of such collateral evidence, save in the last 

 instance, besides much evidence in the case of the 

 first two, positively opposed to the correctness of the 

 recorded weights ; while the last case has been reported 

 without detail. In any long series of observations on 

 brain-weight there are always found a few macro- 

 cephalic brains. For example, in Bischoff's tables, giving 

 the weight of 559 male brains, there are 59 cases above 

 1,501 grammes, and 18 cases above 1,601 grammes, and 

 one, a mechanic, with a brain- weight of 1,925 grammes. 

 It happens that among these 59 cases given by BischofT, 

 there is one learned man, Dr. Hermann of Munich, 

 13 criminals of various sorts, and next to the mechanic 

 just mentioned, comes a day labourer, with a brain- 

 weight of 1,770 grammes. These conditions would be 

 found repeated in other long series. It follows, there- 

 fore, that within a given series there is no evidence that 

 the persons possessing the very large or macrocephalic 

 brains, form the more intelligent fraction of the group. 

 In this group, also, the female brains of the macroce- 

 phalic type, as shown in Table 24, never attain so great 

 a weight as in the case of the males, although statisti- 



