xviii Journal of Comparative Neurology. 



more individuals are born than survive to procreate their kind ; the law of 

 variation, that these individuals are not all alike; and the struggle for 

 existence, by which those who fall below mediocrity are eliminated, while 

 those who excel, interbreeding with average individuals, tend to rise the 

 standard of mediocrity in the succeeding generation. A wolf- spider and 

 his wife are cunning in their awful stalking of unwary flies. They have a 

 numerous family. Some are inferior in cunning to their parents, some 

 equal them, a few excel them. But flies are scarce, and there is not 

 enough food for all. Only two can get a living, but these two are just the 

 mast cunning of the whole brood. Of the numerous family produced by 

 these selected individuals, only two again survive to continue the race, 

 and they the very cleverest of the lot. They have not inherited any cun- 

 ning individually acquired by their parents, but they are terminal products 

 of a series of fortunate variations in the direction of cleverness. 



It is clear that there is no inherited experience here. The relation of 

 this process of natural selection to experience seems indeed to be this. 

 Learning by experience in the individual is a process of tri.il and error, 

 erroneous response being checked. Learning by experience in the race is 

 also a process of trial and error, individuals who failed to accommodate 

 themselves to their surroundings, as the result, of their indi\ idual experi- 

 ence, being eliminated. In the one case erroneous responses, in the other 

 erroneous respondents, are eliminated. There is no inheritance of experi- 

 ence, on the view above indicated, but those individuals who best profit 

 by experience are selected and transmit their ability so to do. 



Now what is the relation of natural selection to psychogenesis or the 

 development of mental symbolism.'' If we say that it has been a factor 

 and a most important factor in its development, we must be clearly under- 

 stood to mean by developement, guidance along certain lines, not origin or 

 initiation. Though the struggle for existence may have caused the elimi- 

 nation of these individuals in which the mental symbolism was relatively 

 imperfect or deficient, natural selection does not give us the law of its 

 infernal development. 



What is the function, if one may so say, of the mental symbolism in 

 the animal world? To enable the organism so to guide its actions as to 

 resjst elimination, to live out its full span of life, and to procreate its kind. 

 Those organisms in which this function is performed in the most efficient 

 manner have survived through the operation of natural selection. Be it 

 so. But the power of efficient control must have been there, given in the 



