192 EVOLUTION AND MAN S PLACE IN NATURE 



to intelligence. In their highest phases, they belong 

 to forms of life possessing organs of touch quite 

 special in their sensitiveness. So far as continu 

 ance of the species depends on these wonders of 

 instinct, dependence of the larvse is much, greater 

 on external conditions, apart from the mother s care, 

 than is the case in the life of the young of the higher 

 mammals. 



A problem is here left outstanding for the evolu 

 tionist, which is still of sufficient difficulty to make 

 us readily appreciate the opening statement of Darwin 

 in his chapter on this subject : Many instincts are 

 so wonderful that their development will probably 

 appear to the reader a difficulty sufficient to over 

 throw my whole theory. The difficulty may seem 

 less puzzling when the problem is more completely 

 freed from the entanglements which have been 

 allowed to gather around it, specially when it is seen 

 that the argument as to animal intelligence must be 

 dealt with on data entirely apart. On the other hand, 

 how much of the evidence relied on as favouring 

 evolution of intelligence must disappear on the same 

 account, may be judged by reference to a single ex 

 ample. Darwin reasons thus as to the intelligence 

 of apes : The anthropomorphous apes, guided pro 

 bably by instinct, build for themselves temporary plat 

 forms ; but, as many instincts are largely controlled 

 by reason, the simpler ones, such as this of building 

 a platform, might readily pass into a voluntary and 

 conscious act. 1 The building of a temporary platform 

 connecting the branches of a tree, so constructing a 

 resting-place for the night, does not stand high as an 



1 Descent of Man, p. 82. 



