242 Berri/ and Bii'lincr: 



We do not think that any unprejudiced person can study this 

 table and deny that as regards classes there is an undoubted correla- 

 tion between size of head and intelligence, or, put more accurately, 

 between cubic capacity of brain, as estimated from three diametral 

 head niea.surenients, and intelligence. This statement is the more 

 probable inasmuch as it is strongly supported by the work of Glad- 

 stone, Matiegka, and Costa Ferreira, to which reference has already 

 been made, and w'hose work supports in every detail the general con- 

 clusion here drawn. In view of the fact that Venn and Galton. 

 quoted by Haddon (16), have shown for 100(1 Cambridge students 

 that education prolonged into years of adolescence, as amongst 

 students at a University, increases the size of the brain, we fail to 

 see hoAv the thesis can be contested. We are, of course, aware that 

 many of the opponents of the view talk somewhat vaguely of quality 

 of brain rather than quantity. It has. however, been proved by 

 Fle<'sliig that the short association fibres of the human cerebral 

 coi'tex do not myelinate until such time after birth as education 

 and the exercise of the intellect have stimulated different parts of 

 the ccrebal cortex to act in harmony. If tliere be no education at 

 all. these fibres do not myelinate, an<l. consequently, such a brain 

 could not. other things being equal, ever attain the same size as the 

 ))i:iiii ill which such nerve fibres had myelinated. 



Similarly with the statement previously quoted from Miss Lee 

 that " personally I am inclined to hold with Professor Peai'son that 

 the conqilexity of the convolutions of the l)raiii, and the variety of 

 its commissures, rather than its actual size, ai-e the characters we 

 might expect to differentiate raec from race and sex from sex, and 

 to have developed with man's civilisation "" ; to us it would rnthei- 

 appeal as though increased complexity of cerebral convoliitious 

 ^nealls an increased number of Inaiii cells and of axones of cells, and 

 consequently an increase in size of brain, and that the commissures 

 cannot be more varied without a cori-esponding increiise in the com- 

 missural exones, and a consequent ron (•s]»on<ling increase in the 

 size of the brain. This line of aigunu-nt is supported by the well- 

 known aMthropological fact that man's civilisat ion has restdted from 

 a steady increase in cubic ca])acity of brain from /'itfirrfiiifhn>/ni.< 

 ertcliis with his lUOU cc. of brain through the men of the ])alaeolithic 



