THE FACTS AND FUNCTION OF SKX 33 



sliould be rather regression to the racial average, or 

 mean, than " progressive variation " from it. Again, 

 it is found, as we have already seen, that partheno- 

 genetic and asexual reproduction are accompanied by 

 abundant variation, though, on the theory of Weis- 

 mann, there should be none whatever in such cases. 

 Further, the biometricians — the new school of biolo- 

 gists who study the facts by the most rigid mathe- 

 matical methods — have shown that, in general terms, 

 the descree of resemblance between individual struc- 

 tures sexually produced and between individual 

 structures asexually produced^ is the same: a fact 

 which " renders it impossible to accept Weismann's 

 view that one of the results produced by the differen- 

 tiation of animals and plants into two sexes is an 

 increase in the variability of their offspring." 

 Further, the variation of parthenogenetically pro- 

 duced " brethren " amongst one of the Aphides and 

 the Daphnia is found to be not dissimilar to that 

 observed as the result of sexual reproduction. And 

 measurements of a very lowly animal, the paramoe- 

 cium, in which sex has not been evolved at all, point to 

 the same conclusion, viz. that, as Karl Pearson says, 

 "Variability is not a product of bi-parcntal inherit- 

 ance. . . . Whatever be the physiological function 

 of sex in evolution, it is not the production of 

 greater variability." Or, to quote the actual words 

 of Mr. Archdall Reid, from whom I have taken the 

 previous quotation : " Though nearly all biologists 

 have supposed that progressive ^ variation, and there- 



1 See p. 45. 



2 It may here be noted in anticipation that progressive and re- 

 gressive are terms applied to variations accordini;ly as whether 

 they tend away from or back to the type of the species. There is 

 no moral significance in the terms. 



C 



