7 o 



PHYSIC 



nerve impulse, these fibres, therefore, become the most 

 important vehicular agents in the economy of nutrition 

 of skin and muscle, especially in the so-called trophic 

 work and oversight of certain nerve centres, which physio- 

 logy persists in assigning to some hitherto ill-defined 

 nervine areas, in conjunction with the distributive agency 

 of the blood circulation and subsequent metabolism ; and, 

 consequently, interference with this nutritive work in the 

 way of increase, diminution, or perversion, becomes a 

 pathological factor of the most vital importance. Thus 

 increase of the peripheral or afferent nerve terminal 

 exfoliation, excretion, or shedding, is followed by hyper- 

 trophy of the cutis and cuticular textures, while increased 

 motor excretion is in like manner followed by hypertrophic 

 changes in the sarcous elements of the voluntary muscular 

 textures ; in like manner, also, decrease in the afferent 

 nerve fibre pabulum leads to the production of "glossy 

 skin" or dermal atrophy, while decrease in the efferent 

 nerve fibre pabulum leads to the production of myopathy 

 or muscular atrophy, the determining cause in both cases 

 being abnormal supply of nervine pabulum or inefficient 

 metabolism on the part of the affected structures. 



In conjunction with these pathological factors is often 

 associated a pathological condition of the cerebro-spinal 

 lymph circulation, whereby diseased conditions of the 

 above order are modified according to its extent and 

 intensity, and so such conditions as neuritis and myositis, 

 local and general, become evolved, and pursue a course, 

 it may be, at first simple, but gradually becoming more 

 complex as it involves associated non-systemic nervous 

 textures. 



