THE GERM-PLASM THEORY 85 



According to others, as Haycraft, it is a mechanism 

 for keeping the race constant an absolutely 

 opposite conclusion. Karl Pearson, from a 

 biometrical study of the results of the two 

 kinds of development, says, " Variability is 

 not a product of bi-parental inheritance. . . . 

 Whatever be the physiological function of sex in 

 evolution, it is not the production of greater vari- 

 ability." And Archdall Reid concludes : 



" Though nearly all biologists have supposed that 

 progressive variation, and therefore evolution, is 

 largely due to bi-parental reproduction, there is, 

 in fact, in the whole range of biological literature 

 not one iota of evidence which supports that view. 

 Men, as in so many instances, have accepted a 

 dogma without proof and have held it without 

 inquiry." 



Here then again we come to a direct and funda- 

 mental difference of opinion amongst men of 

 science as to the interpretation of one of the best- 

 known and most remarkable phenomena of life, 

 that of bisexual development. In the face of this 

 contradiction, what is one to think of theories 

 which are built upon so uncertain a foundation ? 

 That the question should be discussed ; that any 

 number of facts should be brought together ; that 

 provisional hypotheses should be set up with a 

 view to seeing how facts tally with them all this 

 is well. But that such hypotheses should be erected 

 into dogmata and belief in them demanded, is to 

 ask more than one is prepared to concede. 



Weismann's " vital units " live their own lives, 



