50 
training in civilized races being usually 
more adequate in the case of man than of 
woman would, perhaps, explain why man 
has progressed more rapidly in size than 
woman. It seems impossible, taking vari- 
ation as a measure of the intensity of selec- 
tion, to reconcile the relative increases in 
size of man and woman with any direct ef- 
fect of natural selection. 
8. To sum up, then, the following results 
seem suggested by these measurements. 
(i.) Civilized man has progressed gener- 
ally on primitive man in size, variation and 
correlation. 
(ii.) This progression can hardly be ac- 
counted for by increassd selection (because 
of the increased variation), not by decreased 
selection (because it is inconsistent with the 
relative changes in male and female size). 
It might possibly be accounted for by de- 
creased selection and improved physical 
conditions. 
Gii.) Woman is more variable than man 
in civilized races. 
(Giv.) Woman is more highly correlated 
than man in civilized races. 
(v.) In uncivilized races the sexes are 
more nearly equal in the matter of size, 
variation and correlation than in the case 
of civilized races. 
(vi.) It is impossible to say that civilized 
woman is nearer to the primitive type than 
civilized man, for while civilized man differs 
more from the primitive type than civilized 
woman, so far, probably, as absolute size is 
concerned, he has made only about half her 
progress in variation, and hardly any prog- 
ress at all in correlation. 
(vii) The causes (e. g., lessening of selec- 
tion) which tend to increase variation may 
also increase correlation. In other words, 
the intensity of the struggle for existence is 
not necessarily a measure of the intensity 
of correlation.* 
* The mathematical theory of selective correlation 
shows that the close selection of an organ, say the 
SCIENCE. 
[N.S. Vou. VI. No. 132. 
The measurements made by Mr. Warren 
on the Libyans, the results of which he has 
kindly favored us with, are, on the whole, 
fairly in accordance with the above con- 
clusions. He finds for the 
Mean of the sexual ratio of the means.............. 1.092 
Of ee oe the variations......... 1.028 
ce G6 oi the correlations.......1.068 
The corresponding quantities for the 
French are: 1-109, 0:939, 0-956, or, we 
concluded, that in passing from unciyil- 
ized to civilized peoples, from Libyan to 
French, the men gain on the women in 
size—here very slightly, and the women 
gain upon the men very markedly in varia- 
tion and correlation. 
These results are merely suggestions, but 
they may possibly serve to emphasize the 
importance of a careful measurement of the 
long bones of, say, 100 members of both 
sexes for a series of civilized and uncivilized 
races. In the former case at least there 
does not appear to be any real difficulty, 
except the need of codperation, in obtaining 
measurements similar to those of M. Rollet, 
for both English and Germans. The value 
of such statistics for comparative purposes 
would be very great. 
Axicr LEE, 
KARL PEARSON. 
MIGRATION OF THINGS AND OF MEMORIES. 
In the minds of some students the ques- 
tion of migration of forms is frequently con- 
founded with that of the migration of tribes. 
It must not be forgotten by those who are 
carefully studying the origin of industrial 
forms on the Western World that there 
were daily mails delivered on the Ameri- 
can shore from the Eastern Continent, from 
the remotest antiquity. 
The United States Navy has been drop- 
ping bottles overboard in the Atlantic 
femur, may actually tend to reduce the correlation 
between two other organs, say the humerus and the. 
radius. 
