No b04] bIJORltn IhlKIl^ [ s^H)\s 



since obedience to his two rules is not in tlie least contingent 

 upon the magnitude of the variations upon which selection is 

 based, it must be admitted that the facts summarized above are 

 entirely irrelevant to the present discussion. They neither bear 

 upon the phenomena of inheritance, nor add anything to our 

 knowledge of selective elimination. 



The third general fact cited in support of Dr. Pearl's conten- 

 tion ro<ranlin;z the (liininislicd csU'om in wliicli natural selection 



the ])owvv ol personal, uinncdiate. mdivuliiiil, snuiatic adaptation to the 



It IS affirmed m addition, that m eonsecpience of this power of 

 personal adaptation the survival expectation of an individual is 

 not generally and regularly a function ot any static, single- 

 valued relation between its somatic structure, habits or physiol- 

 ogy, on the one hand, and the impinging environmental stresses 

 on the other. Yet, it is asserted, such a relation is implicitly 

 assumed m that part of the theorv of natural selection winch 

 affirms a -selective elimination on the basis ot somatic char- 



The reply to these various statements is. that their substantial 

 truth may be admitted without the possihilit\ tint i\olnti(.n i^ 

 affected by selective elimination being thfrchv in tlic least 

 diminished. The adaptive capabdity ot aiiv nuiividual either 

 rests upon or lacks a germinal basis. In the tonuer case there 

 IS no obvious reason why it should not itself i)n)vule material 

 upon which selective elimination might be based, with consequent 

 change in the composition of the population. In the latter, 

 individual adaptability is as incapable of exercising influence 

 upon the course of evolution, as side-sprig shoidd be, if it were a 

 useful character of the same order of importance. 



If the accumulated results of genetic research provide no 

 more (>tt"e('tiv(> arguments tlian tliese. it must remain an open 



th.' r.Niilts as.Tilu'd io' it 



For manv h-iritinial^' reasons Dr. I'earl has not treated this 

 ponit at IcimHi in his artu-le under diseussiou. But from the 



