118 EVOLUTION OP LIVING ORGANISMS. 



begins to manifest itself as the tissues become differen- 

 tiated, but as to its phylogenetic origin, we can only say 

 that it appeared when the cerebral hemispheres reached 

 a high state of development. 



Too often the Darwinian doctrines are represented as 

 teaching that success in the struggle for existence is 

 obtained only by tooth and nail, by blood and iron. 

 This is a very mistaken view. Brutality, fraud, greed 

 may secure temporary success ; but the triumph of the 

 human race over the lower organisms, and again of the 

 lower civilisations over the higher, has been brought 

 about, on the contrary, through mutual help, co-operation, 

 self-sacrifice. These are the very bonds which hold 

 societies together. Religion, art, and science all play an 

 important part in evolution ; and morality appears not as 

 an external force working against a ruthless and unmoral 

 Cosmic Process, but as a product of that very process, 

 and an all-important factor in its development. In the 

 long run, it is those civilisations which are founded on 

 justice and liberty, on law and order, which will succeed 

 best and last longest. 



Man has conquered in the struggle for existence not so 

 much because his body is more powerful, his movements 

 quicker, or his senses sharper than those of other animals, 

 but because of his great capacity for retaining the im- 

 pressions of past responses, and for bringing them to 

 bear on the response to new stimulations. To this he 

 owes his marvellous powers of adaptation to new and 

 varying conditions. And this great development of 

 associative memory has been accompanied by a corre- 

 sponding enlargement of the brain, especially of the 

 cerebral hemispheres. There can be little doubt that 

 the giant mammals of past ages failed, in spite of their 

 formidable offensive and defensive weapons, partly be- 

 cause their nervous system was not sufficiently de- 

 veloped. Their brain was absurdly small as compared 

 with that of ordinary mammals of to-day; indeed, it 



