ON THE NEURON 339 



needed, or where they can be retained, as conveniently 

 available nerve pabulum. These latter changes coincide 

 with the thickening, and shrinking, or convolution, of the 

 cerebro-vesicular walls, the partial obliteration, or narrowing 

 of the neuro-vesicular cavity, and its definite curtailment, 

 to the proportions of the cerebral ventricles, and the central 

 canal of the cord, and are co-extensive with the duration 

 of life, or, at any rate, of that period of life connected with 

 its adult activities, physical, and mental. 



Life, so far as it is dependent on the integrity of the 

 nerve structures, terminates, in accordance with the manner, 

 and order, of failure, of the dual nervous organ, first, it 

 may be, by a break down, in one, or more, parts, of the 

 cerebro-spinal system, and second, it may be, by failure, in 

 part, or in whole, of the sympathetic, or trophic system, 

 the former, not necessarily, terminating the life of the 

 individual affected, the latter, however, terminating in 

 death, partial, or complete, accordingly as it is local, or 

 general in other words, in gangrene of a part, or in death, 

 of the whole body, recovery being possible in the former 

 degree, but impossible in the latter inevitable death, partial, 

 or complete, occurring in all cases, showing that, the inci- 

 dence of mortal change, is largely, if not entirely, due to 

 the cessation of trophic changes, thus demonstrating as it, 

 the sympathetic nervous system, is the first, so it is the 

 last, part, of the combined nervous system, to dominate, 

 and maintain, the continuity of vital action, or life. 



