A STUDY OF THE BIOMETRIC CONSTANTS OF ENGLISH 
BRAIN-WEIGHTS, AND THEIR RELATIONSHIPS TO 
EXTERNAL PHYSICAL MEASUREMENTS. 
By J. BLAKEMAN, B.A., M.Sc, assisted by ALICE LEE, D.Sc, and 
KARL PEARSON, F.R.S. 
(1) Introductory. 
The purpose of this paper is to present a biometric analysis of the measure- 
ments provided by Dr R. J. Gladstone and published in this volume. The 
conclusions reached are therefore of the same order of validity as the data upon 
which they are based. An attempt has been made to compare them with the 
fuller material reduced by Dr Raymond Pearl, and in many points where 
comparison was possible general confirmation of his conclusions has been 
obtained. Gladstone's statistical material differs from that used by Pearl in 
two essential points. It is in the first place more meagre, but in the second 
place it provides additinnal measurements which enable us to predict with a 
moderate degree of accuracy brain-weight from external measurements on the 
living subject. The characters I'ecorded by Gladstone were the age {A), stature {S), 
cause of death, the maximum head-length {L), the maximum head-breadth {B), 
the auricular height {H), the horizontal circumference {U), and the brain- weight (w). 
The sagittal arc, nasion to inion, and the biauricular transverse arc {Q of our 
notation) were also measured, but are not considered, as the difficulty of 
determining the inion, and the impediment formed by the hair, especially in the 
case of the female subjects, was found to be so great as to make the measurements 
unreliable. The product P — L x B x H was formed, and the present study is 
concerned with the biometric relations of lu, A, S, L, B, H, P, and U. The 
distribution of the work has been as follows : The whole of the labour of 
obtaining the multiple regression formula, p. 146, for the males fell to J. Blakeman, 
the similar formula for the females to A. Lee. All the other statistical and 
calculating work throughout the paper as well as the preparation of Figures 3 — 6 
is further due to J. Blakeman. K. Pearson is responsible onl}' for suggesting the 
general lines the paper should take, and preparing the draft of its final form. 
In dealing with Gladstone's material a reduction was first made in its 
amount by 
(a) the exclusion of a small number of foreigners ; 
{h) the exclusion of those individuals for whom all the seven characters 
referred to above were not available ; 
