of species.  It is not apparent either that we are greatly in need of another faculty, or that we could make use of it even if by a chance mutation it should emerge, since with the power of abstraction we are able to do any class of work we know anything about.  Moreover, the brain is less likely to make a leap now than in earlier time, both because the conditions of nature are more fixed or more nearly controlled by man, and hence the urgency of adjustment to sharp variations in external conditions is removed, and because the struggle for existence has been mitigated so that the unfit survive along with the fit.  Indeed, the rapid increase in idiocy and insanity shown by statistics indicates that the brain is deteriorating slightly, on the average, as compared with earlier times.[269]

Nature is not producing a better average brain than in the time of Aristotle and the Greeks.  If we have more than the wisdom of our ancestors, our advantage lies in our specialization, our superior body of knowledge, and our superior technique for its transmission.  At the same time, the individual brain is unstable, fluctuating in normal persons between 1,100 and 1,500 grams in weight, while the extremes of variation are represented, on the one side, by the imbecile with 300 grams, and the man of genius with 2,000 on the other.  It is therefore perfectly true that by artificial selection—­Mr. Galton’s “eugenism”—­a larger average brain could be created, and also a higher average of natural intelligence, whether this be absolutely dependent on brain weight or not.  But it is hardly to be expected that a stable brain above the capacity of those of the first rank now and in the past will result, since the mutations of nature are more radical than the breeding process of man, and she probably ran the whole gamut.  “Great men lived before Agamemnon,” and individual variations will continue to occur, but not on a different pattern; and what has been true in the past will happen again in the future, that the group which by hook or by crook comes into possession of the best technique and the best copies will make the best show of intelligence and march at the head of civilization.

III

The foregoing examination of the relation of the mental faculty of the lower races to the higher places us in a position to examine to better advantage the other question of the relation of the intelligence of woman to that of man.

The differences in mental expression between the lower and the higher races can be expressed for the most part in terms of attention and practice.  The differences in run of attention and practice are in this case due to the development of different habits by groups occupying different habitats, and consequently having no copies in common.  Woman, on the other hand, exists in the white man’s world of practical and scientific activity, but is excluded from full participation in it.  Certain organic conditions and historical incidents have, in fact, inclosed her in habits which she neither can nor will fracture, and have also set up in the mind of man an attitude toward her which renders her almost as alien to man’s interests and practices as if she were spatially separated from them.