ON THE NEURONS, GENERALLY 333 



have displayed to us, the concluding stage, of the develop- 

 ment, and growth, of every peripheral neuron, sensory, 

 and motor ; the opening stages being the formation of 

 the parent cell, with its nucleus, and nucleolus, and the 

 projection of an axonal process along a nerve trunk, and 

 finally its, outgrowth, and expansion, or termination, in the 

 concluding intricacies of the nerve terminal developments. 

 This, therefore, we hold, proves, that every axonal 

 nerve fibre originating from a cell (and they all originate 

 thus), can only grow in a direction leading from that cell, 

 that is, along the axon, which leads from it, as distinguished 

 from its dendrons, which lead to it, and that, consequently, 

 the long vexed question, of the direction of the growth of 

 nerve, may be now regarded as settled, without the possi- 

 bility of cavil, because it is settled on lines, dictated, and 

 determined, by, and through, the medium of nerve histo- 

 logical continuity, and not by the manner, or direction, of 

 the performance of nerve function, or the passage of nerve 

 energy. In concluding, or summing up, thus, we must 

 be understood as denying that nerve terminal extensions, 

 by whatever name known, are in any respect to be 

 regarded as nerve cells, or neuronal units, and, hence, 

 affirming that it is impossible for a process of growth to 

 be established, or maintained, by them, and that, therefore, 

 growth, and renewal, of nerve, from its distal extremity, 

 is an impossibility. 



