Chapter VIII

TRANSMISSION BY INHERITANCE AND PROPAGATION.

Universality of Inheritance and Transmission by
Inheritance.—Special Evidences of the same.—Human Beings
with four, six, or seven Fingers and Toes.—Porcupine
Men.—Transmission of Diseases, especially Diseases of the
Mind.—Original Sin.—Hereditary Monarchies.—Hereditary
Aristocracy.—Hereditary Talents and Mental
Qualities.—Material Causes of Transmission by
Inheritance.—Connection between Transmission by
Inheritance and Propagation.—Spontaneous Generation and
Propagation.—Non-sexual or Monogonous
Propagation.—Propagation by Self-Division.—Monera and
Amœba.—Propagation by the formation of Buds, by the
formation of Germ-Buds, by the formation of
Germ-Cells.—Sexual or Amphigonous Propagation.—Formation
of Hermaphrodites.—Distinction of Sexes, or
Gonochorism.—Virginal Breeding, or
Parthenogenesis.—Material Transmission of Peculiarities
of both Parents to the Child by Sexual
Propagation.—Difference between Transmission by
Inheritance in Sexual and in Asexual Propagation 175

CHAPTER IX.

LAWS OF TRANSMISSION BY INHERITANCE. ADAPTATION AND
NUTRITION.

Distinction between Conservative and Progressive
Transmission by Inheritance.—Laws of Conservative
Transmission: Transmission of Inherited
Characters.—Uninterrupted or Continuous
Transmission.—Interrupted or Latent
Transmission.—Alternation of
Generations.—Relapse.—Degeneracy.—Sexual
Transmission.—Secondary Sexual Characters.—Mixed or
Amphigonous Transmission.—Hybrids.—Abridged or
Simplified Transmission.—Laws of Progressive Inheritance:
Transmission of Acquired Characters.—Adapted or Acquired
Transmission.—Fixed or Established
Transmission.—Homochronous Transmission (Identity in
Epoch).—Homotopic Transmission (Identity in
Part).—Adaptation and Mutability.—Connection between
Adaptation and Nutrition.—Distinction between Indirect
and Direct Adaptation 203

CHAPTER X.

LAWS OF ADAPTATION.

Laws of Indirect or Potential Adaptation.—Individual
Adaptation.—Monstrous or Sudden Adaptation.—Sexual
Adaptation.—Laws of Direct or Actual
Adaptation.—Universal Adaptation.—Cumulative
Adaptation.—Cumulative Influence of External Conditions
of Existence and Cumulative Counter-Influence of the
Organism.—Free Will.—Use and Non-use of
Organs.—Practice and Habit.—Correlative
Adaptation.—Correlation of Development.—Correlation of
Organs.—Explanation of Indirect or Potential Adaptation
by the Correlation of the Sexual Organs and of the other
parts of the Body.—Divergent Adaptation.—Unlimited or
Infinite Adaptation 227

CHAPTER XI.

NATURAL SELECTION BY THE STRUGGLE FOR EXISTENCE. DIVISION
OF LABOUR AND PROGRESS.

Interaction of the two Organic Formative Causes,
Inheritance and Adaptation.—Natural and Artificial
Selection.—Struggle for Existence, or Competition for the
Necessaries of Life.—Disproportion between the Number of
Possible or Potential, and the Number of Real or Actual
Individuals.—Complicated Correlations of all Neighbouring
Organisms.—Mode of Action in Natural
Selection.—Homochromic Selection as the Cause of
Sympathetic Colourings.—Sexual Selection as the Cause of
the Secondary Sexual Characters.—Law of Separation or
Division of Labour (Polymorphism, Differentiation,
Divergence of Characters).—Transition of Varieties into
Species.—Idea of Species.—Hybridism.—Law of Progress or
Perfecting (Progresses, Teleosis) 252