ON NEURONOGENESIS 349 



its faculties of renewal and redistribution of the common 

 supply of these kept up to the physiological standard. 



The systemic nervous system is thus the product of the 

 sympathetic nervous system, and exists on plasmic matter 

 provided by that system, as well as largely on potential 

 energy produced by that system physiological circum- 

 stances which ensure absolute precision in the combined 

 materio-dynamic working of the two systems, and the 

 greatest possible and best possible output of vital 

 production, physical, chemical, and vital, on the part of 

 both systems. Moreover, the highest or psychic form of 

 work is only possible when the psychic neurons have been 

 rested and refreshed by inhibition from neural contact, 

 sensory and motor, in the form of sleep, during which 

 the ever-active sympathetic nervature renews lost or spent 

 neuronal energy and material, and refits the mind, the 

 psychic being, for intellectual occupation or psychic cerebra- 

 tion, and the sensory and motor nervatures, as well as the 

 musculo-skeletal structures, for another period of activity. 



The histological continuity or contiguity of the entire 

 units of the neuronal commonwealth, its growth from the 

 same nutritive matrix, and their circulational distribution 

 to the skin, and musculo-skeletal framework of the body, 

 by its sensory and motor axons respectively, provide a 

 self-contained materio-dynamic organism, which, with its 

 sympathetic partner, is capable of performing a kind and 

 an extent of work altogether unapproached in the scale of 

 animal performance and reserved for man alone. 



In conclusion, we would generalise to the effect that 

 although the ectodermal extension into the meso- and 

 hypo-dermal areas somewhat overshadows, in extent and 

 importance, the mutual extension of these two latter into 

 the domain of purely neuronic growth and development, 

 it is more apparent than real, inasmuch as it is found that 

 all three have been progressing on lines mutually 

 advantageous and necessary to complete the future 

 complete organism. Thus, as the neuronal axons become 

 structurally one with the muscle plates, the axonal 

 circulation finds a ready prepared non-neuronal textural 

 basis into which it can empty its contents along definite 

 lines and in definite quantities, and which, guided by these 



