IV PREFACE. 



concerned with the maintenance of the species leads necessarily to a 

 profound alteration of our views regarding its origin, although the vast 

 problems thus raised necessarily remain open for fuller separate treat- 

 ment. It is right, however, to say that the restatement of the theory 

 of organic evolution, for which we here seek to prepare (that not of 

 indefinite but definite variation, with progress and survival essentially 

 through the subordination of individual struggle and development to 

 species-maintaining ends), leads us frankly to face the responsibility of 

 thus popularizing a field of natural knowledge from which there are so 

 many superficial reasons to shrink, and which knowledge and ignor- 

 ance so commonly conspire to veil. For if not only the utmost 

 degeneracy be manifestly connected with the continuance of organic 

 species, but also the highest progress and blossoming of life in all its 

 forms, of man or beast or flower, it becomes the first practical applica- 

 tion of biological science not only to investigate and map out these 

 two paths of organic progress, but to illuminate them. Hence we 

 have attempted to indicate the application of the general organic 

 survey, which has been our main theme, to such questions as those of 

 human population and progress, although here, more even than else- 

 where, our treatment can be at best only suggestive, not exhaustive. 

 While limits of space have made it impossible to give the botanical 

 side of our subject its proportionate share of attention, our illustrations 

 of the essential facts are sufficient so show the parallelism of the repro- 

 ductive processes throughout Nature. 



It remains to express our thanks to Professor F. Jeffrey Bell for 

 some valuable suggestions while the work was passing through the 

 press; to Mr. G. F. Scott-Elliot for assistance in summarizing certain 

 portions of the literature; and to our engravers, Messrs. Harry S. 

 Percy, F. V. M'Combie, and G. A. Morison, especially to the first- 

 named, who has executed the great majority of our illustrations with 

 much care and skill. 



PATRICK GEDDES. 



J. ARTHUR THOMSON. 



