CoGiTic Evolution of Man 



603 



break down, and largely disappear during mental activity and 

 resulting fatigue. After rest and repair of the tissues, the 

 granules gradually increase in quantity and sharpness (p. 235). 

 Illustrations of such cells are given below. 



c ^Mi^ 



Fig. 28. — a, ganglion cell from Crayfish (after Pfliicke) showing numerous 

 fine neuratin granules intimately associated with the nerve fibrils; h, stained 

 ganglion cell from infant (after Ewing) showing large dark neiu'atin granules; 

 c, stained ganglion cell of Rabbit with neuratin granules as in h. 



Here is definitely suggested, then, a substance that becomes 

 used up as mental energy is expended, and that gradually ac- 

 cumulates again as this energy is recuperated. In all prob- 

 ability this energy, that we have called cogitic, is itself derived 

 from, and is a greatly more condensed exhibition than is, the 

 cognitic, that seems to energize and traverse the chromatin 

 substance. For it is noticed that, during activity and exhaus- 

 tion of the ganglion cells, the chromatin of the nucleus, and 

 specially of the nucleolus, becomes reduced at the same time 

 that the neuratin becomes first l)roken up and then largely ab- 

 sorbed. When rest ensues the nucleolar chromatin, as well as 

 the neuratin, accunuilate in quantity and assume a normal 

 aspect {86, 18: 101; 19: 125). 



Again between the cogitic and cognitic energizing material 

 on the one hand, and the biotic on the other, there evidently 



