392 
Measurement of Internal Capacity of Skull 
to his objection. Comparing the mean diameters found from more than 100 
English (/ skulls with the means found on more than the same number of living 
heads we have differences of 9, 12, and 11 mm. in the case of maximum length, 
breadth and auricular height respectively. Dr Lee's allowance of 11 cms. seems 
therefore a very reasonable one, and is closer than it appears, for the heads were 
certainly — allowing for the difference of skull and head — more brachycephalic than 
the earlier skulls. We do not say that Dr Lee's method is beyond criticism ; on 
the contrary we recognise all the inherent difficulties of the problem. But we 
believe these difficulties to be enormously exaggerated by Dr Beddoe, and that he 
screens behind this exaggeration the far greater difficulties associated with his 
own method of arc measurement. 
(13) As to his application of that method to demonstrate the correlation of 
intelligence and skull capacity, we hold it to be quite fallacious. To begin with 
he selects a formula — by guesswork — which is theoretically incorrect. He drops 
his formula for the skull and takes the product of ^ of each of his arcs, and divides 
this product by 2000. He then increases it by ^ per cent, for every unit of the 
cephalic index above 50. In his cranial formula he made no correction for cephalic 
index when it was 80. He now drops the neutral index to 50 without any justifi- 
cation or explanation. As we have already seen that the correlation between 
cephalic index and the capacity of the English skull is negative, his formula will 
tend to exaggerate the capacity of the brachycephalic and lower the capacity of 
the dolichocephalic individual heads. Now we believe it to be a fact — whatever 
may be the explanation, lie it in environment, nurture or difference of race — that 
the well-to-do classes in this country are now more round-headed than the working 
classes*, but such are the classes which produce the bulk of the people who work 
intellectually, and therefore Dr Beddoe's erroneous allowance for brachycephaly 
directly tends to emphasise the cranial capacity of the intellectual classes. 
Dr Beddoe says that according to Dr Lee there is no correlation between the 
development of the intelligence and the cranial capacity, and remarksf : 
Les materiaux sur lesquels cette derni^re opinion est basee sent rares et peu concluants. 
Dr Lee makes no such statement at all. What she asserts is J: 
" That there is no marked correlation between skull capacity and intellectual 
power." 
Dr Beddoe forgets to draw attention to the fact that Dr Lee, in conjunction 
with ourselves, has actually measured the relation between size of head and intelli- 
gence, and on far more ample material than Dr Beddoe uses. We find the corre- 
lation sensible, but so small that it is impossible to base any prediction from 
the size of head as to general intelligence§. As to Dr Beddoe's own data bearing 
* See inter alia MacJonell, Biometrika, Vol. i. p. 190. 
t Loc. cit. p. 267. 
t Phil. Trans. Vol. 196, A, p. 259. 
§ R. S. Proc. Vol. 69, pp. 333—42 and Vol. 71, p. 106 et seq. 
