CHAP. XX.] OF THE HUMAN BRAIN. 349 



calculated to afford race -averages, or prevailing-weights, 

 where a sufficient number of skulls are carefully measured 

 by a method likely to give uniform and correct results. 



It must never be forgotten, however, that the size of 

 the Skull, and with it the weight of the Brain, varies 

 within certain limits according to the stature of the 

 individual, in such a way that increments of increasing 

 stature are accompanied by increments of increased Brain - 

 weight, though the extent of the latter increments goes 

 on diminishing as the stature increases. This statement 

 rests on the authority of Marshall,* who has also calculated 

 from the colossal tables 

 (together with private 

 notes) supplied byBoyd, 

 that for English people, 

 with a mean range in 

 stature of 7 inches for 

 males, the correspond- 

 ing variation in Brain- 

 weight is 2 '75 oz., and 

 that for females, with a 

 mean range in stature 

 of 6 inches, the varia- 

 tion is Only 1*25 OZ. In FlG - 1S2. Human Cerebrum and Cerebellum, 

 , , . showing the relative size of these parts of the 



comparing the brain- Braiu . (After mrschfeid and Leveiiie.) 

 weights of individuals 



of different stature, therefore, with the view of tracing the 

 influence of other conditions over the weight of the organ, 

 it must always be borne in mind that difference in stature 

 itself is a potent cause of difference in brain-weight which 

 ought to be allowed for in the first instance. 



It may be well to state here, in general terms, that 

 rather less than -gth of a total Brain -weight will, for 



* " Proceed, of Eoy. Soc.," 1875, vol. xxiii. p. 564. 



