An Introduction to a Biology 



istics of Mendelian and biometric theory and so to put myself 

 in a position to discuss their mutual relationship. 



With regard to the scope of this essay, there is one point 

 I wish to emphasise : it may be that some critic will lay 

 down this pamphlet with the remark that all that he has 

 read may be very true, but that the fact remains that the 

 only thing which " matters " is the mass-phenomenon ; or 

 another may declare that the key which will unlock the 

 secret of heredity can only be obtained by a study of the 

 properties of the germ-cells. I do not propose to express 

 an opinion on either of these contentions, but I wish most 

 strongly to insist that when a man has made either of them, 

 he has stepped from one country into another. After dis- 

 cussing the mutual relation of two theories, he suddenly 

 asserts that after all it is only one of them that matters — as 

 one who during a discussion of the evidence for and against 

 the existence of mental activity after the death of the brain 

 should declare that after all, belief in such a survival was 

 a great comfort to many : both questions may be worth 

 discussing, but they should be discussed separately. In 

 this essay I propose to treat of the mutual relations of the 

 two theories purely as theories, without touching on the 

 question of their possible value to the pure or applied biologist. 



The reader may easily convince himself by a perusal of 

 the literature on this subject that the self -same facts are 

 interpreted by the rival schools of thought in the light of 

 their own theories ; and if he looks for recognition from either 

 party that there may be something of truth in the opinions 

 of their opponents, he will search in vain. I do not propose 

 to discuss the opposite points of view, because I believe 

 that the remedy for the present inconclusiveness of the dis- 

 cussion lies very deep, and is to be found in the clear appre- 

 ciation of the fundamental relation between the biometric 

 and Mendelian points of view.^ 



1 The reader who wishes to follow the discussion of the facts at first hand 

 will find the necessary references to four cases in the Appendix {see p. 161). 



146 



