x displayed greater manual
dexterity. According to the present results, that depends on
what is meant by manual dexterity. If it means the ability to
make very delicate and minutely controlled movements, then it
is slightly better in men. If it means ability to co-ordinate
movements rapidly to unforeseen stimuli it is clearly better
in women.[44]

We have no other than a utilitarian basis for judging some variations
advantageous and others disadvantageous. We can estimate them only
with reference to activity and the service or disservice to the
individual and society implied in them, and a given variation must
receive very different valuations at different historical periods in
the development of the race. Departures from the normal are simply
nature's way of "trying conclusions." The variations which have proved
of life-saving advantage have in the course of time become typical,
while the individuals in which unfavorable variations, or defects,
have occurred have not survived in the struggle for existence.
Morphologically men are the more unstable element of society, and this
instability expresses itself in the two extremes of genius and idiocy.
Genius in general is correlated with an excessive development in
brain-growth, stopping dangerously near the line of hypertrophy and
insanity; while microcephaly is a variation in the opposite direction,
in which idiocy results from arrested development of the brain,
usually through premature closing of the sutures; and both these
variations occur more frequently in men than in women. There is also
evidence that defects in general are more frequent in men than in
women.

A committee reported to the British Association for the Advancement of
Science, in 1894,[45] that of some 50,000 children (26,287 boys, and
23,713 girls) seen personally by Dr. Francis Warner (1892-94) 8,941
were found defective in some respect. Of these, 19 per cent. (5,112)
were boys, and 16 per cent. (3,829) were girls.

An examination of 1,345 idiots and imbeciles in Scotland by Mitchell
showed the following distribution of the sexes:

Male Female Male Female
Idiots 430 284 or 100 to 66.0
Imbeciles 321 310 or 100 to 96.5

showing that "the excess of males is much greater among idiots than
among imbeciles; in other words, that the excess of males is most
marked in the graver forms of the