26 
Variation and Correlation in Brain- Weight 
It appears then that, so far as the available material may be considered valid 
as representing the whole population, the conclusion is justified that the Hessian 
and Swedish peoples are sensibly alike in respect to their brain-weight. The 
agreement would be closer than that actually observed if the assumption made in 
the course of reasoning here followed, that the regression of brain-weight on age 
and stature is strictly linear, were exactly true. As will be shown later these 
regressions are not strictly linear but they approach linearity with sufficient 
closeness to serve for all practical purposes. This, together with the difference in 
age distribution of the " total " and " young " series, also accounts for the fact that 
while in the " total " series and male " young " series the gross differences between 
Swedes and Hessians are lowered when we reduce to a common "stature-age base," 
these differences are slightly increased, on the other hand, when we deal in the 
same way with the shorter female "young" series. 
This is in agreement with the general fact that these peoples are probably the 
most closely related ethnically of any with which we are dealing in the present 
paper. The Swedes may be considered to be among the purest representatives of 
the original blonde, dolichocephalic Teutonic i^ace (Ripley* and Denikerf). In 
the case of the Hessians some intermixture of this Teutonic with the brachy- 
cephalic, characteristically brunette Alpine type has occurred. The differentiation 
from the Swedes in such important characters as skull form and stature is not 
great however|. 
Turning now to the other racial groups discussed, viz., the Bavarians and 
Bohemians (Czechs), we find as would be expected, that the differences in brain- 
weight are greater. Using the Hessian data as a basis for comparison, the gross 
differences with their probable errors are exhibited in the following table : 
Total Males: Hessian mean — Bavarian mean =28'552 + 4'763. 
Total Females: Hessian mean — Bavarian mean = 39-519 ±5'618. 
Young Males: Hessian mean — Bavarian mean =36'646±5'842. 
Yomig Females : Hessian mean — Bavarian mean =44'698 + 6-577. 
Total Males: Bohemian mean — Hessian mean = 53-102 ±5'286. 
Total Females : Bohemian mean — Hessian mean =51-039 + 6-212. 
Young Males: Bohemian mean — Hessian mean = 54-394 + 6 -462. 
Young Females: Bohemian mean — Hessian mean = 33-708 ±7-551. 
In all cases the differences are seen to be well above what might arise from 
errors in statistical sampling. Reducing to a common " stature-age base " by the 
method followed above the following results are obtained : 
* Eipley, W. Z.: The Races of Europe, New York, 1899, pp. xxxii, 624. 
f Deniker: The Races of Man, London and New York, 1900, pp. xxiii, 328 and 611. 
X This is well shown graphically in the maps indicating the distribution of stature and cephalic index 
in Europe, given by Kipley (loc. cit. pp. 96 and 53). Cf. also Deniker, loc. cit. pp. 328 and 329. 
