NATURAL SELECTION 95 



But the point on which I wish now to lay stress is, that in some 

 cases it does not persist as an insignificant remnant, but dis- 

 appears completely. Here, at anyrate, economy of growth can- 

 not help us, and we seem driven to attribute the disappearance 

 of the last remnant to what Weismann has called "pammixis" (I 

 spell the word after the improved fashion now followed, since 

 the barbarous word panmixia offended some pedantic zoologists, 

 and prevented them from giving the hypothesis a fair considera- 

 tion). Pammixis means simply free intercrossing. Weismann 

 assumes that in every species the predominant tendency is to- 

 wards reversion, and that it is only checked by rigorous Natural 

 Selection. Professor Lloyd Morgan, in discussing the question, 

 starts with a different assumption. " Let us suppose," he says, 

 " that nine individuals are born, and that the size of some organ 

 varies in these from one, the most efficient, to nine, the least 

 efficient. The birth mean will, therefore, be as shown on the 

 left hand side of the following table, at the level of number five, 

 four being more efficient, four less efficient. But if, of these 

 nine, six be eliminated, then the mean of the survivals will be as 

 shown on the right hand side of the table. 



I 



2 survival mean 



3 

 4' 

 birth mean 5 



eliminated individuals 



The result, then, of the cessation of selection will be to re- 

 duce the survival mean to the birth mean." l "But unless this 

 be accompanied by a tendency to diminution due to economy of growth or 

 fome other cause? this cannot produce any reduction." 3 This 

 seems to me like a begging of the question. What we have to 



1 Animal Life and Intelligence, p. 172. '* Italics mine. 3 Loc. tit. 



