254 COMPARATIVE PHYSIOLOGY OF THE BRAIN 



By difference in the resonance I mean the ease with 

 which associations are produced. It is necessary, for 

 example, in the case of a great complex of sensations, 

 that the images of memory which correspond to cer- 

 tain constituents of that complex are easily repro- 

 duced, and in the case of a very elementary sensation 

 greater images of memory, which contain that ele- 

 mentary sensation as a constituent, should be repro- 

 duced. The quality of resonance is perhaps the more 

 important, as long as the capacity does not fall below 

 the average. The intelligent man differs from the 

 stupid man, among other things, in the ease with which 

 by means of the associative memory he makes the 

 analysis or synthesis of the complexes of sensation : 

 that is, in the slow or stupid man only such images of 

 memory are called up associatively as were con- 

 nected before with the entire stimulating complex ; 

 while in the quick thinker complexes of memory are 

 also produced associatively which are connected with 

 single elements of the stimulating complex. 



6. After what has been said, it is clear that the ab- 

 solute mass of the brain cannot be the principal factor 

 in determining intelligence (10). In different races 

 of dogs, for instance, the brain varies just as much as 

 the weight of the body. Dogs of a small breed may, 

 however, be more intelligent than dogs of a large 

 breed. It also follows from this that the relation of 

 mental activity to the metabolism of the central 

 nervous system is totally different from that of mus- 

 cular activity to the metabolism of the muscle. The 



