12 METHODS OF EVOLUTION [CHAP. 



twenty years, following in Darwin's footsteps ; 

 who, in his later years, advanced precisely what 

 ecologists now maintain, " that sub - varieties 

 can be formed without the aid of Natural 

 Selection." 



Darwinians usually make a somewhat sharp 

 distinction between permanent hereditary struc- 

 tures as hands and muscles, and their develop- 

 ment from infancy to the adult stage as being 

 acquirements due to use. Thus, Mr Reid tells 

 us that " adaptive acquirements " are, e.g., a 

 muscular or a weak arm. Such being the 

 results of use and disuse respectively. 



" But modifications acquired as a result of 

 use and disuse are clearly never transmitted 1 

 . . . nearly all the developmental changes which 

 occur between infancy and manhood are attri- 

 butable to it." 2 



He had previously observed : 



"An infant's limb never attains to the adult 

 standard except in response to stimulation 

 similar to that which developed [but what first 

 evolved] the parent's limbs ? 3 Plainly, then, that 

 which is transmitted to the infant is not the 

 modification, but only the power of acquiring 

 the modification under similar circumstances" 

 (Author's italics). 



1 Op ctY., p. 34. But if the strong muscles of a cat, by which it 

 makes great leaps for its size, be not hereditary, how is it that tiny 

 kittens can make similar leaps several times their own height 

 without any practice at all ? A baby can support its own weight. 

 2 Op tit., p. 35. J Op cit., p. 34. 



