﻿2 DARBISHIRE, Mendelian and Biometric Theories. 



expected to ask and to which the specially trained 

 biologist may be expected to supply an answer. 



It is the thesis of the present essay to demonstrate 

 the compatibility of Mendelian and biometric theory and 

 to account for their apparent antagonism. 



A few words as to the spirit and scope of this essay 

 seem to me to be necessary. There are two methods of 

 scientific criticism, if indeed one of them can be justly 

 called scientific. One arises from a determination to 

 crush a theory, while the other consists in the postpone- 

 ment of the attack until every endeavour has been made 

 to appreciate the exact point of view of the upholders 

 of that theory, and in a willingness to put off the attack 

 for ever if the theory should not be found wanting after 

 all. The most flagrant example of the first kind of 

 criticism, on which I can lay hands, flowed from the pen 

 of a writer who, after having misrepresented the theory he 

 was attacking by declaring that it was " an essential part 

 of the Mendelian hypothesis that the (so-called 'extracted') 

 recessive individual which is produced by pairing two 

 first crosses, is in every respect similar to the original 

 pure recessive,"* concludes with these words : " This mouse 

 is clearly not a pure dominant, because it produces albinos ; 

 it is not a dominant hybrid because it has pink eyes ; 

 and it cannot be a recessive because when paired 

 with an albino it produces some black-eyed forms." It 

 is evident from this quotation that the stimulus which 

 actuated the author was a desire to stultify and refute 

 Mendelian theory at all costs, and that he did not make 

 the smallest attempt to discover what Mendelian theory 

 really was or to put himself in the position of those who 

 held it to be true. For an example of the second form 

 of criticism I suggest that the reader may turn to the 

 * A. I). Darbishire, Biometrika 3 Vol. II., pp. 282 and 2S5. 



