174 EVOLUTION 



nant of something useless natural selection 

 will not interfere, and the determinant will 

 continue getting weaker every generation. 



The theory of germinal selection is, of 

 course, an hypothesis, dealing like Mendel's 

 theory of gametic segregation with the in- 

 visible, but it may be nevertheless useful 

 in enabling us provisionally to formulate a 

 number of very puzzling facts, and in sug- 

 gesting experimental work, on which, even- 

 tually, we must base our conclusions as to 

 these abstruse questions. 



According to Weismann, germinal selection 

 helps us to understand the dwindling away 

 of organs which have sunk below the level 

 touched by ordinary natural selection; the 

 occasional exaggeration of organs beyond the 

 limits of demonstrable utility, as may be 

 illustrated in artificial conditions by the six 

 feet long tail-feathers of some Japanese 

 cocks; the occurrence of definitely directed, 

 appropriate, and simultaneous variations, 

 and much more besides. It plays into the 

 hands of personal selection ; or, as Weismann 

 more elegantly phrases it, 'it supplies the 

 stones out of which personal selection builds 

 her temples and palaces: adaptations." 



FAMILY AND GROUP SELECTIONS.- -Though 

 Darwin did not wholly overlook this (indeed 

 in at least one notable passage he expresses 



