THE ORIGIN OF THE HUMAN SOUL 213 



vestige of itself, the process of relaying the past could never 

 be resumed, and we would lose our personal identity every 

 twentj'-four hours. The mind, or subject of thought, then, 

 must be an abiding and unitary principle distinct from our 

 composite bodies, and from our manifold and fleeting 

 thoughts. 



Finally, to the two foregoing attributes of the human soul 

 (substantiality and simplicity), we must add a third and 

 crowning attribute, namely, spirituality. It is this, and this 

 alone, that differentiates the human from the bestial soul, 

 which latter is but an incomplete complement of matter, in- 

 capable of existence apart from matter, and doomed to perish 

 with the dissolution of the organism, as the cylindrical form 

 of a candle perishes with the consumption of the wax by the 

 flame. 



All the psychic activities of the brute, such as sensation, 

 object-perception, imagination, associative memory, sensual 

 emotion, etc., are organic functions of the sensitivo-nervous 

 type. In all of them the agent and recipient is not the soul 

 alone, but the psycho-organic composite of soul and organism, 

 that is, the soul-informed sensory and central neurons of the 

 cerebrospinal system. The sensory neurons are nerve cells 

 that transmit centerward the excitations of physical stimuli 

 received by the external sense organs or receptors, in which 

 their axon-fibers terminate. These receptors and sensory 

 neurons are extended material organs proportioned and spe- 

 cialized for receiving physical impressions from external 

 bodies, either directly through surface-contact with the bodies 

 themselves or their derivative particles {e.g. in touch, taste 

 and smell), or indirectly through surface-contact with an 

 extended vibrant medium such as air, water, or ether (e.g. in 

 hearing and sight). The central neurons of the cerebral 

 cortex are, as it were, the tablets, upon which the excitations 

 transmitted thither by the sensory neurons, record the ex- 

 tended neurograms that constitute the physical basis of the 

 concrete imagery of memory and imagination. Interior senses, 



