276 BRAINS OF RATS AND MEN 



farther than does this aspect of the question in the 

 case of the seismograph. 



The backward view of the rise of cortical func- 

 tions envisages two fields of very unequal visibiUty: 

 first, the foreground of the history of the personal ex- 

 perience of the individual; and, second, the back- 

 ground of his whole phylogenetic history. The first 

 field is open to casual inspection, and more careful 

 examination reveals the chain of events which mark 

 the steps in the fabrication of one's equipment of 

 habits, in the accumulation of the data which con- 

 stitute his knowledge, and in the formation of those 

 mental attitudes and idiosyncrasies that we call 

 "character." A retrospect into the second field, the 

 field of hereditary endowments, requires an ascent 

 from the level of simple observation to the higher 

 ground of biological research with the aid of much 

 optical and other scientific equipment, and the dim 

 horizons of this wider territory have been but im- 

 perfectly explored. 



The scientific evidence already in hand, some of 

 which has been cited in the preceding discussions, is 

 adequate to reveal an orderly sequence of biological 

 processes whose phylogenetic movements can be fol- 

 lowed, in broad outline at least, with a high degree of 

 probability and whose final result is the "original 

 nature," or innate endowments, of the individual 

 man. In the course of his personal career the events 

 of his daily life have been woven into the warp and 



