Neuralgia. 187 



ing in the absence of any structural lesion whatever. A priori 

 one can with difficulty escape the conviction that neuralgia must 

 exist in the lower animals as in man, and the only drawback to its 

 recognition is the difficulty of diagnosis. 



The first step in such diagnosis must usually be the presence of 

 lameness, stiffness or indisposition to fr^e movement of some par- 

 ticular muscle or group of muscles deriving their innervation from 

 a particular nerve. Or there may be a particular position habitu- 

 ally assumed such as semi-closed eyelids, drawn back ears, laterally 

 inclined neck which strongly suggests nervous suffering. Next, 

 there must be the exclusion of any appreciable structural cause 

 and especially of inflammation. The three prominent features of 

 the pain of inflammation is that it is aggravated by pressure, it is 

 heightened by movement, and it is accompanied by some decided 

 alteration of the function of the part. If there are at the same 

 time exudation and swelling, inflammation is all the more certainly 

 indicated. In a neuralgic pain on the contrary pressure does not 

 increase the pain : it may even alleviate it : moyement of the part 

 may be rather satisfactory to the patient than painful ; and the 

 disturbance of function, contractile, secretory, trophic, is not per- 

 ceptible. There is no local exudation nor swelling to account for 

 the nervous disorder. 



The liability to confound the affection with a neuritis more 

 centrally situated, but the pain of which is referred to the peri- 

 phery of the nerve, is to be obviated by a tracing, of the nerve 

 along its course to the nerve centre so as to identify any centre of 

 tenderness, and also by the implication of all the peripheral 

 branches coniing off ectal of that point. 



Again, rheumatism may be easily confounded with neuralgia, 

 but here the affected nerve and muscle and even the skin over it 

 is liable to be very tender to the touch or pinch, and if at all 

 acute some hyperthermia is present. lyike rheumatism, neuralgia 

 shows a tendency to shift from place to place. 



Pains due to pressure on the nerves by tumors.'aneurisms, and 

 other swellings, are constant, whereas neuralgic pains are marked 

 by remissions and aggravations and even by intervals of complete 



relief. 



Causes. The toxic neuralgias are illustrated by chronic lead 

 poisoning, in which, in man, there are wandering pains like those 



