164 Human Personality. 



Beneath the layer of pyramidal cells there is also found 

 in the cerebral cortex a " nuclear " layer of small rounded 

 cells, some of which have protoplasmic processes as seen 

 in the cerebellum ; and there is also a fusiform group. 



We find that the entire surface of the cortex cerebri is 

 composed mainly of these marvelous networks, associated 

 with the plexuses of blood capillaries and the adjuvant 

 neuroglia required for their physical support and mainte- 

 nance. The superficies of the cortex, indeed, is by far the 

 most remarkable structure of which minute anatomy has 

 knowledge. The extent and intricacy of the fibrillar 

 threads, loops, and twigs, formed by the mutual interlac- 

 ing and interlooping of the thousands of tree-like branches 

 which the cells send upward into it, are quite incomparable. 

 In this respect the cortex of the brain is a hundred times 

 more dense and more involved than are the tops of the 

 trees in a dense forest. The branches, in their amazing 

 ramifications, not unfrequently extend to a distance of 

 twenty times the length of the cell body. It is as if each 

 tree of a thick forest sent forth vines for- branches, which 

 climbed to a distance of several hundred yards, dividing 

 as they proceeded into a thousand vinelets and tendrils, 

 which enwrapped and entwined everything in their course. 

 Such a jungle, growing to a height of several hundred 

 feet, would no more than illustrate this astonishing lace- 

 work of the protoplasmic fibrils of the cortical cells. 



Histologists were early led to inquire with wonder as to 



