THE REPRODUCTIVE FACTOR IN EVOLUTION. 315 



SUMMARY. 



1. A brief review of the history of evolution theories, and of the 

 present state of the question. 



2. A reproductive factor in evolution has been hinted at by a few 

 naturalists. 



3. Further indications of the importance in evolution of reproductive 

 and species-regarding, as opposed to the nutritive and self-maintaining 

 activities. 



LITERATURE. 



See articles by the writers in " Chambers's Encyclopedia," especially 

 Biology, Botany, Environment, Evolution, and minor articles, 

 such as Ccelenterates, Flower, Fruit, &c. ; also "Encyclopaedia 

 Britannica," Sex, and Variation and Selection ; also Geddes, A 

 Restatement of the Theory of Organic Evolution (Summary in Proc. 

 Roy. Soc, Edin., 1888-89, still unpublished). 



Spencer, Mivart, Eimer, Wallace, Weismann, &c. — Op. cit. 



