potentiality of emotion
that has something formidable about it. Obviously the varieties of
mankind differ much in respect of this trait. Apart from kind of
feeling, they are unlike in amount of feeling. The dominant races
overrun the inferior races mainly in virtue of the greater quantity of
energy in which this greater mental mass shows itself. Hence a series of
inquiries, of which these are some:--(_a_) What is the relation between
mental mass and bodily mass? Manifestly, the small races are deficient
in it. But it also appears that races much upon a par in size--as, for
instance, an Englishman and a Damara, differ considerably in mental
mass. (_b_) What is its relation to mass of brain? and, bearing in mind
the general law that in the same species, size of brain increases with
size of body (though not in the same proportion), how far can we connect
the extra mental mass of the higher races, with an extra mass of brain
beyond that which is proper to their greater bodily mass? (_c_) What
relation, if any, is there between mental mass and the physiological
state expressed in vigour of circulation and richness of blood, as
severally determined by mode of life and general nutrition? (_d_) What
are the relations of this trait to the social state, as nomadic or
settled, predatory or industrial?

2. _Mental complexity._--How races differ in respect of the more or less
involved structures of their minds, will best be understood on recalling
the unlikeness between the juvenile mind and the adult mind among
ourselves. In the child we see absorption in special facts. Generalities
even of a low order are scarcely recognized, and there is no recognition
of high generalities. We see interest in individuals, in personal
adventures, in domestic affairs, but no interest in political or social
matters. We see vanity about clothes and small achievements, but little
sense of justice: witness the forcible appropriation of one another's
toys. While there have come into play many of the simpler mental powers,
there has not yet been reached that complication of mind which results
from the addition of powers evolved out of these simpler ones. Kindred
differences of complexity exist between the minds of lower and higher
races; and comparisons should be made to ascertain their kinds and
amounts. Here, too, there may be a subdivision of the inquiries. (_a_)
What is the relation between mental complexity and mental mass? Do not
the two habitually