344 NATURAL SCIENCE. May, 



by destroying such individuals as have facuUies in some respects 

 below the mark. Natural Selection is thus credited with an all-round 

 elevating power, for it raises all faculties to a higher \e\e\ than they 

 would otherwise have fallen to. Why, then, does its power abruptly 

 cease at a certain line ? If it can thus lift all faculties up to the mark 

 under ordinary conditions, why cannot it raise them slightly above 

 the mark if those conditions become more stringent ? If it previously 

 counteracted a general retreat all along the line, why cannot it now 

 cause a general advance ? Will an increase of eliminative and 

 selective rigour produce no extra effect ? 9 And if it raises aggregates 

 of faculties, must it not raise the separate faculties of which the 

 aggregates are composed ? The complex evolution of many co-ordi- 

 nated organs simultaneously is, of course, a much slower and more 

 difficult process than the special evolution of a single organ or faculty 

 which becomes exceptionally useful ; but difficulty is not impossi- 

 bility, and we are, therefore, fully at liberty to believe, with Darwin, 

 that Natural Selection alone would suffice to bring about the many 

 co-ordinated changes necessitated by the gradual development of the 

 huge horns of the Irish elk or the long neck of the giraffe. As a 

 matter of fact, complex evolution of special organs and complicated 

 instincts has taken place without the help of use-inheritance, and in 

 spite of the strongest opposition it can offer, as is seen in neuter 

 insects, such as bees, and still more in some species of ants, where 

 workers, soldiers, and another distinct caste, apparently of overseers, 

 are descended from innumerable generations of helpless parents who 

 do not develop various organs and instincts which the neuters alone 

 can improve by exercise but cannot possibly transmit to posterity. 

 To hold that Natural Selection is totally incapable of bringing about 

 complex evolution is to hold that the evolution of bees and ants is 

 impossible. Seeing, then, that Natural Selection has evolved the 

 (relatively) huge head and fighting mandibles of the soldier-ant, ^° with 

 all the complex co-ordinated changes involved, there is no reason for 

 supposing that it cannot have effected similarly complicated changes 

 in larger animals, such as the elk and the giraffe. 



The influence of beneficial modifications in determining survival 

 is not easily measured. Advantages may often be more decisive than 

 we are apt to suppose. Thus the discriminative tactile sensibility of 

 the tip of the tongue seems to have been of some importance in 

 promoting welfare and survival. It greatly aids the sense of taste in 

 securing fit and proper nutrition — a consideration entirely overlooked 

 by Mr. Spencer. While constantly exploring small irregularities of 



^ This rigour might give itself fuller scope by first increasing fertility as a point 

 of supreme importance or absolute necessity. 



10 Among termites, too, the soldier caste possesses " enormously large, hard, and 

 strong heads, almost as big as the rest of their bodies, and these are armed with 

 gigantic and very strong and sharp mandibles, while the heads and mandibles of the 

 non-combatant workers are much smaller and weaker." 



