Reginald J. Gladstone 
115 
weight follows very closely the dimiaution in the size of the head, as is shown by 
the following table, which gives the proportion between these two quantities in 
4 groups of 50, arranged according to age and sex. The size of the head is here 
indicated by a figure obtained from the product of the three principal diameters 
(L X B X H) expressed in millimetres, the first four figures of this number 
represent the number of cubic centimetres which would be contained in a rect- 
angular block having the same diameters as the cranial portion of the head, and 
I shall refer to it subsequently as the ' index of size ' of the head, thus : 
(196) X (156) X (138) = 4219488. 
4219, the 'index of size' of the head, represents cubic centimetres and may 
therefore be conveniently compared Avith the weight of the brain expressed in 
grammes. 
Males 
H 
L 
B 
Index of 
size 
Brain- 
weight 
Index of Size 
Brain-weight 
Number in 
each group 
Age, 20—IfG 
134-8 
190-8 
149-5 
3876 
1370-5 
2-806 
50 
„ Jf-G and upwards 
132-4 
189-8 
148-7 
3736 
1316-1 
2-838 
50 
Females 
Age, SO— 4G 
129-8 
183-4 
144-9 
3449 
1223-5 
2-818 
50 
„ IfG and upwards 
128-2 
182-1 
143-5 
3350 
1195-7 
2-801 
50 
By combining the male with the female groups, we obtain the following ratios 
between the size of the head and the brain-weight : 
Age, 20-46 . . . 2-812 
„ 46 and upwards . 2 819 
In comparing the extreme ends of the series, however, it appears that the 
diminution in brain-weight, with the advance of age, is more rapid than the 
diminution in the size of the head ; thus taking the mean of 4 and 3 % cases 
over 70 years of age, the ratio between size of head and brain-weight is 2-821, 
whereas an equal number of cases between 20 and 25 years of age give 2-702. 
The influence of stature upon the ratio between the outside measurements of 
the head and the brain-weight is apparently very small ; but it has a marked 
influence on the actual size of the head as compared with the general mean, and a 
less but measurable influence on the proportion of the size of the head to the body 
in the individual. In other words, tall men in the aggregate have larger heads 
than short men, but proportionally to the size of their bodies their heads are con- 
siderably smaller than those of short men. 
The formula which I have employed to express this relationship of the size of 
the head to the stature is the following : 
100 X 
i/ Index of size 
Ex. 
Stature in centimetres 
15-77 cm. X 100 
v^3921 cm.^' X 100 
170 cm. 
Capitulo-statural index 
1577 
170 cm. 
170 
9-27. 
15—2 
