304 Practical Application [CH. 



In the pre-Mendelian period, indeed, such an expression 

 had no definite meaning. From a knowledge of the 

 physiology of descent under uniform conditions it may be 

 possible to proceed to a determination of the consequences 

 following a change in those conditions. We cannot in- 

 vestigate both unknowns at once. In the analysis of these 

 wider problems we must begin with the more tractable of 

 the two, and it has become obvious that this is to be found 

 in the genetic aspect of the phenomena. 



The outcome of genetic research is to show that human 

 society can, if it so please, control its composition more 

 easily than was previously supposed possible*. Whether 

 such control should be exercised, or the form which it is to 

 take, scarcely falls within the province of this text-book to 

 discuss. Nevertheless, as many are already becoming urgent 

 in advocating the practical application of genetic science to 

 human affairs, some few words on that subject may be 

 appropriate. Whatever course civilisations like those of 

 Western Europe may be disposed to pursue, there can be 

 little doubt that before long we shall find that communities 

 more fully emancipated from tradition will make a practical 

 application of genetic principles to their own population. 



The power is in their hand and they will use that 

 power like any other with which science can endow them. 

 The consequence of such action will be immediate and 

 decisive. For this revolution we do well to prepare. 



Interference may take one or both of two courses. 



* Mr F. Gallon's long-continued efforts have at length been successful 

 in directing public attention in some degree to the overwhelming im- 

 portance of Eugenics. Some of the earlier attempts in the same direction 

 are worth remembering. For example, Sir W. Lawrence frequently adverts 

 to the subject in language almost identical with that now current. " The 

 hereditary transmission of physical and moral qualities, so well understood 

 and familiarly acted on in the domestic animals, is equally true of man. 

 A superior breed of human beings could only be produced by selections 

 and exclusions similar to those so successfully employed in rearing our 

 more valuable animals. Yet in the human species, where the object is of 

 such consequence, the principle is almost entirely overlooked. Hence all 

 the native deformities of mind and body, which spring up so plentifully in 

 our artificial mode of life, are handed down to posterity, and tend, by their 

 multiplication and extension, to degrade the race." (W. Lawrence, Lectures 

 on Physiology, Zoology, and the Natural History of Man, London, 3rd Ed. 

 1823, p. 393. See also ibid. pp. 260 and 389.) 



