190 WHAT IS LIFE 



Size and complexity of the Z-system of the brain 

 directly determine, or are an index of, the degree of 

 psychic power proper to the individual. It obviously 

 follows that the length of the period of infancy must 

 be accepted as a standard of measurement for rating 

 the intellectual standing, the intelligence, of a race, or 

 people. 



The various measurements that have been made 

 heretofore in research on the problem of the difference 

 in intelligence between one race and another race 

 (comparisons of anatomical structure, cerebral con- 

 volutions, etc.) all admittedly have been unsatis- 

 factory in that they have established no definite 

 means for rating intelligence. One investigator, 

 Franklin P. Mall, expresses himself thus: "Argu- 

 ments for differences due to race, sex, and genius will 

 henceforward need to be based upon new data, really 

 scientifically treated and not of the older state- 

 ments."^^ 



The differences in the weight of the brain that are 

 found to exist, thus far have been perhaps the chief 

 means for rating the intelligence of races. The true 

 value of this difference, however, has been lessened 

 and obscured by the well-known fact that in in- 

 dividual cases the weight of the brain does not serve 

 as an index to psychic power. Thus, as Keith points 



I 



'' American Journal of Anatomy, IX, 1. 



