316 BIOLOGICAL PHYSICS 



as the closing stage, of a prolonged series of formative, 

 or integrative, circulatory, and disintegrative, changes. 

 Thus, the nervous system, the most vital of the many 

 systems of which the corporeal organic whole is made up, 

 may be traced from a primary involution, embryonically, 

 of the epiblast, to a terminal, or final, evolution, or ex- 

 foliation, in the mature stages of development, of the 

 same epiblast, after its prolonged passage through the 

 intricacies of the meso- and hypo-blastic areas, as an 

 unbroken process of growth, and finally of decay 

 representing, what may be denominated, the concluding 

 stage of the long process of developmental, or organic, 

 evolution. 



Moreover, the various stages, of this long develop- 

 mental process, represent, a balanced, and ordered, suc- 

 cession of evolutionary events, the culminating, and 

 crowning, example, of which is typified, and represented, 

 by that under discussion the systemic nervous system, 

 which constitutes the "end and aim" of the great 

 organic " sequence of events," exhibited in the life-history 

 of all the. higher animal bodies. So long, as the integrity 

 of the nervous system, including here the sympathetic 

 nervous system, of an animal body, is maintained in 

 unbroken continuity, so long will the life of that body 

 be maintained, so soon, however, as its maintenance in 

 that condition becomes impossible, will the death of that 

 particular body, in whole, or in part, ensue, according to 

 the general, or local, incidence, of the pathological con- 

 ditions by which it is invaded. 



The entire nervous system, judging from the oneness 

 of its functional work, consisting of, trophic, motor, 

 sensory, and intellectual, activities, must, of necessity, be 

 one, in histological, and anatomical, continuity, or, at 

 least, its component parts, must be in material contiguity, 

 so complete, and intimate, as to permit of functional 

 oneness, and to ensure that it developmentally projects, 

 or interjects, itself, into material, and functional, relation- 

 ship, with every organ, and texture, of the body, thereby, 

 dominating, and controlling, the functional, and organic 

 output, in regard to work, and securing its physiologically 

 measured maintenance, in whole, and in part. 



