INTRODUCTION. 



II n'est pas vraisemblable que 1'evolution sociale se trouve etre 

 exactement 1'inverse de 1'evolution organique. Plus probablement les 

 lois generates induites de 1'observation des etres vivants sont ici a moitie 

 vraies, applicables sur certains points, et portant a faux sur d'autres. 



C. BOUGL. 



When we know that living things are formed of the same elements 

 as the inorganic world, that they act and react upon it, bound by a 

 thousand ties of natural piety, is it probable, nay. is it possible, that 

 they, and they alone, should have no order in their seeming disorder, 

 no unity in their seeming multiplicity, should suffer no explanation by 

 the discovery of some central and sublime law of mutual connection ? 



T. H. HUXLEY. 



Since the publication of my book on Evolution by 

 Co-operation, further evidence in its favour has been rapidly 

 accumulating on all sides, and all biological research, so far 

 as I have been able to follow it in the last year or two, has 

 brought to light strong confirmation on every hand of the main 

 theses I have put forward. 



I purpose now to consider a series of applications of my 

 bio-economic theory with a view to showing that it comple- 

 ments the work of eminent biological writers past and present. 



As a result of further study and of more insight gained, I 

 here give greater emphasis to the factor of symbiosis than in 

 my previous work and concurrently and, as the title of this 

 volume indicates, am presenting a further elaboration of my 

 theory in this direction. 



The first chapter is particularly devoted to the subject of 

 symbiosis, which is generally defined as a physiological 

 partnership between individuals of different species, but which 

 is of far more universal meaning and occurrence than is 

 suggested by this definition. The term must be particularly 

 applied also to the wider bio-economic form of co-operation 

 which underlies evolution and unites all organisms in one vast 

 web of life in a veritable organic "civilisation." 



