THE REPRODUCTIVE FACTOR IN EVOLUTION. 289 



SUMMARY. 



I. A brief review of the history of evolution theories, and of the present state 

 ot the question. 



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

 naturalists. 



III. 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 Encyclopaedia," 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 Soc, Edin., 1888-89, still unpublished).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. 



