new
impressions and to profit by the acquisitions. Inferior and superior
human races are contrasted in this respect. Many travellers comment on
the unchangeable habits of savages. The semi-civilized nations of the
East, past and present, were, or are, characterized by a greater
rigidity of custom than characterizes the more civilized nations of the
West. The histories of the most civilized nations show us that in their
earlier times, the modifiability of ideas and habits was less than it is
at present. And if we contrast classes or individuals around us, we see
that the most developed in mind are the most plastic. To inquiries
respecting this trait of comparative plasticity, in its relations to
precocity and early completion of mental development, may fitly be added
inquiries respecting its relations to the social state, which it helps
to determine, and which reacts upon it.

5. _Variability._--To say of a mind that its actions are extremely
inconstant, and at the same time to say that it is of relatively
unchangeable nature, apparently implies a contradiction. When, however,
the inconstancy is understood as referring to the manifestations which
follow one another from minute to minute, and the unchangeableness to
the average manifestations, extending over long periods, the apparent
contradiction disappears; and it becomes comprehensible that the two
traits may, and ordinarily do, co-exist. An infant, quickly wearied with
each kind of perception, wanting ever a new object which it soon
abandons for something else, and alternating a score times a day between
smiles and tears, shows us a very small persistence in each kind of
mental action: all its states, intellectual and emotional, are
transient. Yet at the same time its mind cannot be easily changed in
character. True, it changes spontaneously in due course; but it long
remains incapable of receiving ideas or emotions beyond those of simple
orders. The child exhibits less rapid variations, intellectual and
emotional, while its educability is greater. Inferior human races show
us this combination: great rigidity of general character with great
irregularity in its passing manifestations. Speaking broadly, while they
resist permanent modification, they lack intellectual persistence, and
they lack emotional persistence. Of various low types we read that they
cannot keep the attention fixed beyond a few minutes on anything
requiring thought, even of a simple kind. Similarl