12 DARWINISM AND EVOLUTION. 



It should not be forgotten, however, that to become adapted to 

 changing circumstances, some organisms must undergo what has 

 been called " degradation." Loss of size, loss of organs, even loss 

 of intelligence, may be the result of this adaptation. 



Smallness is beneficial when the supply of food is strictly limited, 

 as on an island ; and insular animals are often diminutive, like the 

 Shetland pony and the extinct pigmy elephant of Malta. Small- 

 ness is also of service to creatures that burrow, and they are 

 always less than allied species that live on the surface of the earth. 

 It is obviously advantageous to an animal to be without organs 

 for which it has no further need ; and, though they are slow in 

 disappearing, they may at length vanish altogether. 



That an organism should gain by the loss of intelligence it is 

 more difficult to understand, because we are accustomed to invert 

 nature's pyramid, to set a higher value on mental activity than 

 on physical well-being, to think more of the flower than of the 

 root. Suppose the case of a primitive tribe of hunters, skilled in 

 tracking their prey, who should begin to train dogs for the chase. 

 Suppose the hounds' excellence in bringing home a quarry, 

 associated with their original pleasure in predatory pursuit, to have 

 become hereditary. The men of the tribe need less skill as 

 hunters and less as trainers. Now, skill, which is a form of 

 intelligence, is a stored-up energy, acquired, and in some degree 

 maintained, by an expenditure of force. If an economy of force 

 were physically advantageous in the social condition supposed, 

 such a loss of intelligence would be an indirect gain. 



Rufescent ants are a slave-making species. The slaves of 

 Polyergus rufescens have learnt their duty so well and practise it 

 with so much pleasure and assiduity that their masters have lost the 

 greater part of their instincts. They have ceased to build, they 

 take no care of their young, they do no manner of work, and they 

 cannot even feed themselves. 



As regards our own race, an undue fostering of those who are 

 too ready to receive help is a recognised cause of pauperism and 

 imbecility ; and a lapse of men into savagery takes place when 

 muscular strength and a brutal nature become, for any reason, of 

 more service than culture and skill. So strange are the ways by 

 which an organism adapts itself to its environment, though not 

 always with final success ; for it is probable in the case of the 

 degraded man, and perhaps certain in that of the degraded ant, 

 that we are spectators of a slowly closing scene, and that both 

 races are about to become extinct. 



We have seen that wild animals vary to the great extent of i o 

 or 20 per cent, of their average dimensions. At present, however, 

 external conditions are changing very slowly ; so that these indi- 

 viduals derive no benefit from their variation, and are not better, 

 but may be worse, fitted to survive than the rest. 



