CONTENTS. 



CHAPTER I. 



SYMBIOSIS. 



The law of natural co-operation Importance of study of symbiosis 

 Convoluta roscoffensis and C. paradoxa as examples of symbiosis 

 Lessons of adaptation Importance of nutrition Connection with Bio- 

 Economics Work essential in production of organic capital Living 

 protoplasm equipped for work Organisms as economic agents Evidence 

 that tropistic response is connected with food-attractions Similarities 

 of nutrition and sex in stimulating work and determining evolution 

 Need of restraint and mutual forbearance in symbiosis Plants as eternal 

 symbiotic providers All plants are animal-plants ; all animals are 

 plant-animals Physical separation of partners represents a further 

 evolution of reciprocal differentiation gained by age-long symbiosis 

 Partial plant-animalism in C. roscoffensis Secretions of Convolutal 

 green cells recall those of mammary glands " Love- foods " Relation 

 between coloured and non-coloured Convolutal cells suggests parallel 

 between those of green and non-green cells of ordinary green-plants 

 Domestic and biological symbiosis Nature of plants in the light of 

 symbiosis H. C. Davidson's " plantagen " theory Place of symbiosis 

 in reproduction, heredity and form production generally Asexual 

 inferior to sexual reproduction because of attending inferiorities of 

 symbiosis Sex as the stimulant of values " Love-foods " and Vitamines 

 as symbiogenetic agents Metamorphosis of plantagens and of insects 

 determined by symbiotic conditions Surfeit a retarding factor Com- 

 parison between plantagen, butterfly, rose-aphis and Convoluta An 

 " urgent need of a change of diet " Retrogressive symbiosis Progressive 

 symbiosis and vicarious sacrifice Increase of mutuality and exchange 

 raising the general level of life Simultaneously predaceous types 

 becoming increasingly debarred from participation in progress Expen- 

 diture for self-defence by the plant Animals highly predaceous on 

 plants eventually thrown upon themselves and evolving a " parasitic 

 diathesis " Killing the goose which laid the golden eggs Temporary 

 benefits sometimes result from abandonment of true biological symbiosis, 

 but at the expense of progressive evolution Protracted gestation neces- 

 sary if progressive evolution is to be achieved, possible only in genuine 

 symbiosis Symbiogenesis predetermines the evolution of important 

 organs The corpus luteum and its symbiogenetic significance Convo- 

 lutal "symbiosis" of doubtful character Nemesis of reproduction 



