CHAPTER II. ON THE MANNER OF DEVELOPMENT OF MAN FROM SOME LOWER FORM. Variability of body and mind in man—Inheritance—Causes of variability—Laws of variation the same in man as in the lower animals—Direct action of the conditions of life—Effects of the increased use and disuse of parts—Arrested development—Reversion—Correlated variation—Rate of increase—Checks to increase—Natural selection—Man the most dominant animal in the world—Importance of his corporeal structure—The causes which have led to his becoming erect—Consequent changes of structure—Decrease in size of the canine teeth—Increased size and altered shape of the skull—Nakedness —Absence of a tail—Defenceless condition of man. CHAPTER III. COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS. The difference in mental power between the highest ape and the lowest savage, immense—Certain instincts in common—The emotions—Curiosity—Imitation—Attention—Memory— Imagination—Reason—Progressive improvement —Tools and weapons used by animals—Abstraction, Self-consciousness—Language—Sense of beauty—Belief in God, spiritual agencies, superstitions. CHAPTER IV. COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS, continued. The moral sense—Fundamental proposition—The qualities of social animals—Origin of sociability—Struggle between opposed instincts—Man a social animal—The more enduring social instincts conquer other less persistent instincts—The social virtues alone regarded by savages—The self-regarding virtues acquired at a later stage of development—The importance of the judgment of the members of the same community on conduct—Transmission of moral tendencies—Summary. CHAPTER V. ON THE DEVELOPMENT OF THE INTELLECTUAL AND MORAL FACULTIES DURING PRIMEVAL AND CIVILISED TIMES. Advancement of the intellectual powers through natural selection—Importance of imitation—Social and moral faculties—Their development within the limits of the same tribe—Natural selection as affecting civilised nations—Evidence that civilised nations were once barbarous. CHAPTER VI. ON THE AFFINITIES AND GENEALOGY OF MAN. Position of man in the animal series—The natural system genealogical—Adaptive characters of slight value—Various small points of resemblance between man and the Quadrumana—Rank of man in the natural system—Birthplace and antiquity of man—Absence of fossil connecting-links—Lower stages in the genealogy of man, as inferred firstly from his affinities and secondly from his structure—Early androgynous condition of the Vertebrata —Conclusion.