X CONTENTS 



between Mud and Clear Thinking — Correlation between Catches of 

 Mackerel and Amount of Spring Sunshine — Nutritive Chains in the 

 Deep Sea — Dependence of one Organism on another for the Con- 

 tinuance of the Species — Darwin's Instance of the Connection 

 between Cats and Clover — Scattering of Seeds — Interrelations 

 between Freshwater Mussels and Fishes — Life-histories of Parasites 

 — Far-reaching Influence of Certain Animals : Earthworms — Ter- 

 mites, or White Ants — The Hand of Life upon the Earth — Practical 

 Importance of a Realisation of the Web of Life . . pp. 45-65 



CHAPTER III 



THE STRUGGLE FOK EXISTENCE 



The Idea not so Simple as it seems — The Anthropomorphism of 

 the Idea — Different Forms of the Struggle for Existence — Struggle 

 for Existence in the Plant World — Illustration of the Complexity 

 of the Struggle for Existence — Reasons for the Struggle for Existence 

 — Results of the Struggle for Existence — Breadth of the Darwinian 

 Concept of the Struggle for Existence — The other Side of the 

 Struggle for Existence — Mutual Aid — Application of the Concept 

 to Human Life .....•*. pp- 69-94 



CHAPTER IV 



THE RAW MATERIALS OF PROGRESS 



Organic Progress Primarily depends on Variability — Darwin's 

 Position — Progress since Darwin's Day in Regard to Variation — 

 Variations more Abundant than even Darwin supposed — Proportion 

 between Frequency and Amount of Variations — Correlation of 

 Variations — Brusque Variations more Frequent than was formerly 

 supposed — Discontinuous Variations — Mutations — Darwin's Posi- 

 tion in Regard to Mutations — Origin of Variations — Germinal 

 Selection — Variational Stimuli — Modifications or Acquired Charac- 

 ters — Indirect Importance of Modifications — Modification-Species — 

 Individual Plasticity — Relation to Human Life . pp. 97-126 



