ORGANIC EVOLUTION — ^MENTAL 157 



to stimulation, so as to place themselves in harmony with 

 an environment which has become more complex, and 

 that higher in the scale this power, of which reason is 

 the outcome, increases more and more, till in amphibians 

 and reptiles, the traits acquired by virtue of it sometimes 

 contradict and overpower the dictates of instinct. But 

 even the highest reptiles, with few exceptions, are 

 provided with an equipment of reflexes and instincts 

 suflScient to enable them to enter on the battle of life 

 unaided immediately on emerging from the egg. It is 

 far otherwise with birds and mammals, which, to an in- 

 creasing extent, as they are higher placed in the scale, 

 depend for survival less and less on instinct, on inborn 

 inherited knowledge and ways of thinking and acting, 

 and more and more on reason, on acquired knowledge 

 and ways of thinking and acting ; and therefore to an 

 increasing extent are helpless and unfit for the battle 

 W'hen hatched or bom, and for an increasing length of 

 time are protected by, and receive tuition from, one or 

 other of their parents, whereby they acquire such know- 

 ledge and ways of thinking and acting as enable them to 

 enter on the battle with advantage. 



In the lower birds and mammals, in which the 

 cerebrum is least developed, instinct still predominates 

 over reason. A young chick, for instance, emerges from 

 the egg the possessor of a large amount of hereditary 

 knowledge,* supplemented later by an amount of acquired 



1 " The late Mr. Douglas Spalding, ip his brilliant researches on 

 this subject, has not only placed beyond question the falsity of 

 ' that all the supposed examples of instinct may be nothing more 

 than cases of rapid learning, imitation, or instruction,' but also 

 proved that a young bird or mammal comes into the world with 

 an amount and a nicety of ancestral knowledge that is highly 

 astonishing. Thus, speaking of chickens, which he liberated from 

 the egg and hooded before their eyes had been able to perform any 

 act of vision, he says that on removing the hood after a period 

 varying from one to three days, ' almost invariably they seemed a 

 little stunned by the light, remained motionless for several 

 minutes, and continued for some time less active than before they 



