264 BIOLOGICAL PHYSICS 



The actual differentiation, and division, of the canal, 

 posteriorly, is accompanied by union at its anterior ends 

 in the pituitary body (see Figs. 30, 32), a provision of 

 the most important order in the future evolutional events 

 impending, in that long series constituting the life-history 

 of the human form, in its passage from the embryonic, to 

 the adult, condition. 



The union of the anterior extremities of the neurenteric 

 canal, here effected by the junction of the neural and 

 buccal cavities, produces, or affords, an anterior means of 

 exit, to the fluid contents of the neural half of the canal, 

 when free disposal, or circulation, along the posterior 

 aspect is hindered, by the division and differentiation, 

 there, and there is no longer available, an untrammelled, 

 or unrestricted, condition, of patency that being reduced 

 to the proportion of providing an exit for the coccygeal 

 residuum of the cerebro-spinal fluid. Division and 

 differentiation, of the two canals, having been fully 

 effected, and a start made in the development of their 

 future separate lumens, each becomes provided with a 

 structural machinery, capable of enabling it to perform 

 the functionary work, of an alimentary organ, and of a 

 systemic nervous system, respectively. 



It seems, that during, and after, the completion of the 

 process of differentiation of the neurenteric canal, the 

 great functional work, of the entire body is being appor- 

 tioned to the two nervous systems, as they, and their 

 related textures, and organs, become evolved, and take 

 their place in the great organic commonwealth of the 

 completed and communal, organism. Thus, the vege- 

 tative, or organic, and lower physiological, work, is 

 delegated to the sympathetic nervous system, while the 

 voluntary, psychological, and higher, nervine, work, is 

 delegated to the systemic nervous system, a mixed, or 

 debatable, work, being performed by, one, or the other, 

 or both, in conjunction. It, moreover, seems from 

 physiological, and chemical, observation, warrantable to 

 assume, that the dual, or duplex, dynamic balance, hereby 

 necessitated, is maintained, by mutual exchange, and 

 transference, as well as limited and mutually secured 

 production of energy. 



