476 THE POPULAR SCIENCE MONTHLY 



ASSOETATIVE MATING IN MAN 



By Dk. J. ARTHUR HARRIS 



CAHNEGIB INSTITUTION OF WASHINGTON 



I. Introductory 



^^rr^HE supreme misfortune is when theory outstrips performance." 

 -»- wrote Leonardo da Vinci. 



He gave us, as far as I remember, no illustration of his epigram, 

 but one is at hand in the modern attitude towards the Darwinian prin- 

 ciples of natural and sexual selection. Exalted as they were on com- 

 parative evidence alone, and by post-Darwinian enthusiasts who were 

 not only fertile, but liberal to a fault, in assumption, their debasement 

 was inevitable. We are now in the period of reaction when men dis- 

 parage selection, or dismiss it entirely as an evolutionary factor. 

 Against this unreasonable extreme of opinion these essays^ are directed. 

 They are simple reviews, pretending merely to set forth honestly the 

 results secured by biometricians in their studies of these exceedingly 

 difficult biological problems. 



Their purpose is, I admit, in reality two-fold. Not only are they 

 a direct plea for a more open-minded — a stringently critical rather than 

 a dogmatic — attitude town.rds the Darwinian factors, but an indirect 

 appeal for a wider recognition of the biometric methods which make 

 possible the measurement of the intensity of the primary factors of 

 organic evolution. 



The strongest arguments are those of quantitatively expressed facts. 

 The best way of overcoming the prejudices and other obstacles against 

 which the biometrician works is to allow these facts to speak for them- 

 selves, if possible in terms comprehensible to the layman. 



Let us turn, therefore, to the available facts. 



1. The Problem of Intra-racial Sexual Selection 



There may be forces other than propinquity tending to fuse differ- 

 ent races which through migration or otherwise come to occupy the 

 same territory. Sociologists have, however, long emphasized intra- 

 group marriages as one of the forces which tend to keep them distinct.^ 



^ A first essay, ' ' The Measurement of Natural Selection, ' ' has appeared in 

 these pages, Popular Science Monthly, Vol. 78, pp. 521-538, 1911. 



*For instance, Eipley ("Eaces of Europe," p. 49) says: "However strenu- 

 ously the biologist may deny validity to the element of artificial selection among 



