344. NATURAL SCIENCE. May, 
by destroying such individuals as have faculties 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 level 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. Asa 
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.”’ 
