THE WONDERS OF LIFE 



ference in the complicated fibrils which extend in the 

 cytoplasm of both organs, although our coarse means 

 of investigation have not yet succeeded in detecting 

 this difference. In order to distinguish properly be- 

 tween the two sets of neurona, I propose to call the 

 sensory-cells or sense-centres cFsthetal cells, and the 

 thought-cells or thought-centres phronetal cells. The 

 former are, anatomically and physiologically, the inter- 

 mediaries between the external sense-organs and the 

 internal thought-organs. 



To this anatomic delimitation of the internal sense- 

 centres and thought-organs in the cortex corresponds 

 their physiological differentiation. The sensorium, or 

 sense-centre, works up the external sense-impressions 

 that are conveyed by the peripheral sense-organs and the 

 specific energy of their sensory nerves; the custheta, or 

 the central sense-instruments that make up the sen- 

 sorium, and their organic units, the cesthetal cells, pre- 

 pare the sense-impressions for thought and judgment in 

 the proper sense. This work of "pure reason " is accom- 

 plished by the phronema of the thought-centres, the 

 phroneta (or the various thought-organs that compose 

 it) and their histological elements, the phronetal cells, 

 bringing about an association or combination of the pre- 

 pared impressions. By this important distinction we 

 avoid the error of the older sensualism (of Hume, 

 Condillac, etc.) — namely, that all knowledge depends on 

 sense-action alone It is true that the senses are the 

 original source of all knowledge; but, in order to have 

 real knowledge and thought, the specific task of reason, 

 the impressions received from the external world by the 

 sense-organs, and their nerves and centres, must be 

 combined in the association-centres and elaborated in 

 the conscious thought-centres. Then there is_t.he im- 

 portant, but frequently overlooked, circumstance that 

 there is in advance in the phronetal cells of the civilized 



14 



i"'W*"J*-^ -•■ -""" 



