lids
and arthropods: The external locomotive skeleton leads
to temporary rapid advance, but fails of the goal.--Its
disadvantages.--Vertebrates: The internal locomotive skeleton leads
to backbone and brain.--Reasons for their dominance.--The primitive
vertebrate.

CHAPTER IV

VERTEBRATES: BACKBONE AND BRAIN

The advance of vertebrates from fish through amphibia and reptiles
to mammals.--The development of skeleton, appendages, circulatory
and respiratory systems, and brain.--Mammals: The oviparous
monotremata.--Marsupials.--Placental mammals.--Development of the
placenta.--Primates.--Arboreal life and the development of the
hand.--Comparison of man with the highest apes.--Recapitulation of
the history of man's origin and development.--The sequence of
dominant functions.

CHAPTER V

THE HISTORY OF MENTAL DEVELOPMENT AND ITS SEQUENCE OF FUNCTIONS

Mode of investigation.--Intellect.--Sense-perceptions.--Association.
--Inference and understanding.--Rational intelligence.--Modes of mental
or nervous action.--Reflex action, unconscious and comparatively
mechanical.--Instinctive action: The actor is conscious, but guided
by heredity.--Intelligent action.--The actor is conscious, guided by
intelligence resulting from experience or observation.--The will
stimulated by motives.--Appetites.--Fear and other prudential
considerations.--Care for young and love of mates.--The dawn of
unselfishness.--Motives furnished by the rational intelligence:
Truth, right, duty.--Recapitulation: The will, stimulated by ever
higher motives, is finally to be dominated by unselfishness and love
of truth and righteousness.--These rouse the only inappeasable
hunger, and are capable of indefinite development.--Strength of
these motives.--Their complete dominance the goal of human
development.

CHAPTER VI

NATURAL SELECTION AND ENVIRONMENT

The reversal of the sequence of functions leads to extermination,
degeneration, or, rarely, to stagnation.--Natural selection becomes
more unsparing as we go higher.--Extinction.--Severity of the
struggle for life.--Environment one.--But lower animals come into
vital relation with but a small part of it.--It consists of a myriad
of forces, which, as acting on a given form, may be considered as
one grand resultant.--Environment is thus a power making at first
for digestion and reproduction, then for muscular strength and
activity, then for shrewdness, finally for unselfishness and
righteousness.--