EXTRACT XL 



A COMPARISON OF SOME OF THE DISEASES INCI- 

 DENTAL TO THE AFFERENT AND EFFERENT 

 NERVATURES RESPECTIVELY, BASED ON THEIR 

 PHYSIOLOGY AS BEFORE DESCRIBED, SO AS TO 

 SHOW SOME OF THEIR COMMON CHARACTERIS- 

 TICS AND DISSIMILARITIES. 



THE afferent and efferent, or the sensory and motor nerva- 

 tures or nerve fibrils, are histologically alike, in that they 

 are both axonal processes of nerve cells, that embryonically 

 they are projected into, become amalgamated with, and 

 innervate the skin and voluntary musculature, respec- 

 tively, and that they grow from the nerve cells towards 

 the textures, which they innervate, and not from the tex- 

 tures towards the nerve cells, of which they form the 

 axonal processes, the possibility of this latter occurrence 

 being absolutely precluded from the non-existence at the 

 periphery of either nervature of a neuro-genetic cell 

 mechanism, and because a cell process can only grow from 

 a cell. They are alike, also, in that, besides being merely 

 axonal processes connecting nerve cells with sensory and 

 motor agencies respectively, they convey, along with nerve 

 energy, material pabulum for the growth and maintenance 

 of these agencies in skin and muscle elements respectively, 

 by capillary circulation along the fibrillary lumina, so to 

 speak, of the axis cylinder and medullary containing 

 membranes or tubes ; the dual protoplasmic elements of 

 the axis cylinder and medullary substances thus constitut- 

 ing the material pabulum, * on which the processes of 

 growth and maintenance of much of the muscle and skin 



