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 FOR 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 wan 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 



