i68 Human l^ersonality. 



maintained at a considerable tension during self-eonscious- 

 ness, i. e., during wakefulness. To generate current for 

 maintaininn: the consentience of the brain as a whole, an 

 increased blood supply is requisite ; work is done and 

 energy absorbed. The condition, moreover, gives rise to 

 waste products and leads to exhaustion of the cell, 

 rendering a period of recuperation and rest necessary. 

 The consentient circuit must needs be broken. In sleep, 

 the brain cell ceases to live in its corporate or social 

 capacity and reverts to its old-time, unicellular mode of 

 life. Independent again, it nourishes itself and gains 

 strength and substance afresh. 



Wonderful as are the protoplasmic processes which the 

 neurons put forth, to secure consentience throughout the 

 brain, they are not without their analogue in unicellular 

 life. Amoeba radiosa projects long linear rays, as it 

 floats, to enable it to perceive and draw in food particles. 

 Grcmia terricola projects a net of filamentous rays and 

 snares. Raphidiophrys elegans emits long, lance-like rays, 

 or darts of exceeding tenuity, more minute than the finest 

 fiber of silk. In the case of unicells these filaments are 

 temporary, befitting, the wants and necessities of single 

 cell life. In the case of the neurons the necessity is for 

 filaments continuously extended. 



Revert for a moment and grasp the underlying 

 principle of this vast development of the human per- 

 sonality by the neurons. Ah initio, it founds on that 



