M. A. Lewenz and K. Pearson 
391 
We hope later to publish double regression formulae for skull capacity, but if 
it is to be done by the use of an index, we do not believe that the cephalic index 
is the right character to use, because it has been shown to have small correlation 
with the capacity, and what correlation does exist changes sign from race to race. 
On the whole we believe that increased accuracy is to be sought as we have 
indicated on p. 388* by using non-linear regression rather than multiple regression 
formulae, unless indeed one variable of the latter be the thickness or the weight of 
the skull. 
(12) Having dealt with the application of Dr Beddoe's formula to skulls, we 
now turn to its raison d'etre, i.e. its applicability to the living head. We have 
already considered one grave objection, namely, that the inion is on the skull 
itself by no means a definite and easily located point. On the living head we find 
it even more difficult to determine it with certainty. By throwing the head 
forward in certain cases the boundary of the area to which the muscles are attached 
can be appreciated, but " well-marked inions," i.e. large bony growths in the 
neighbourhood of the inion, occipital ridges and toruses, especially frequent in 
English heads, render the exact localisation extremely problematical. Let us 
suppose, however, that the inion could be ascertained on the living head, then the 
measurement of the three arcs seems to us entirely valueless on account of the 
varying amount of hair. Dr Beddoe really makes no attempt to meet Topinard's 
objection to the use of these arcs on the living head, except by the remark that 
abundance and stiffness of hair is not usually met with in combination with 
intellectual eminence ! He gives no statistics, however, of the relative baldness of 
the average middle-aged agriculturist, tradesman, or man of science. Without 
such statistics his remark is worthless. Having a bad case himself he simply drops 
it in order to point out the difficulties of rival formulae ! Thus he writesf : 
Cette objection en ce qui concerns les cheveux s'applique aussi k la hauteur auriculaire et au 
maximum de longueur et largeur, lorsqu'ils sent pris au cephalom^tre et non avec le compas 
d'epaisseur. 
We do not know to what form of cephalometer Dr Beddoe is referring, but any 
anthropologist would be perfectly incompetent for his task who could not devise 
an instrument for reading the auricular height by a sufficiently blunt point so that 
the determination of the height would not be affected sensibly by the existence of 
the hair. You can clear the hair to one side when measuring the diameters, you 
cannot possibly get it out of the way when using the measuring tape. This is not 
mere theoretical reasoning, but the actual result of experience in practice. Next 
Dr Beddoe endeavours to discredit the allowance Dr Lee has made for the thick- 
ness of the flesh on the living head. It seems to have escaped him that if the 
varying thickness of the flesh is a real difficulty in determining the diameters, its 
effect on his own arcs (in addition to the effect of the hair!) can hardly be 
described as less than insuperable. But we are not inclined to give much weight 
* Phil. Trans. Vol. 192, A, pp. 222 et seq. 
+ hoc. cit. p. 285. 
