ON SLEEP 501 



process of retraction or withdrawal of the communicating 

 dendritic processes of the neuronal commonwealth may 

 be said to resemble what ensues when a countless crowd 

 of " expanded " umbrellas are " drawn down " after a 

 " deluge of rain " ; we would claim, therefore, that this 

 not only synchronises with, but that it is productive of, 

 the inhibition of the process of cerebration, and conse- 

 quently the cause of sleep. We may further infer that, 

 with the growing exhaustion of the cerebral, and other 

 nerve-cell, energy from continued exercise, the dendritic 

 processes naturally become disposed to droop from the 

 lowering supply of energy, and hence finally withdraw 

 from immediate contact with each other and with neigh- 

 bouring dendrons when the act of inhibition becomes an 

 accomplished fact and sleep reigns supreme. 



Meantime the sympathetic nervous system enters on 

 supreme control of all the vital processes and work of 

 the body, restoring, after sleep, to the systemic nervous 

 system, the control of its own particular work, with its 

 machinery burnished up and repairs effected where 

 required, as well as with its nerve energy renewed and 

 made capable of lasting out another diurnal " spell of 

 work." Sleep, therefore, is a thing of the systemic 

 nervous system and by the systemic nervous system, 

 not involving the sympathetic nervous system, except 

 it may be by an increase of work, nor directly the 

 sanguineous circulation, although indirectly that circulation 

 is largely involved, as providing the materials from which 

 the nerve protoplasm is renewed and maintained, as well 

 as much of the lost nerve energy obtained. 



In this collection of neuronal dendritic phenomena is 

 bound up the most cryptic part of the mysterious union 

 of mind and body, of the ego with the non-ego, as well 

 as the mechanism of consciousness ; besides, in this 

 multum in parvo physico-mental region, we are in touch 

 with the supreme physiologico-psychological problems, in 

 the solution of which are involved the destiny of man, 

 mental and physical, with all that is involved therein and 

 flows therefrom. It will thus be realised that, on an 

 absolutely true physiological working of these minute 

 and uncountable textures, depends much of the health, the 



