SECT. XI. PHYSIOLOGY. 101 
but when the same disease becomes chronic, sti- 
mulants are more beneficial than an opposite 
treatment. The same observation is applicable to 
ophthalmia, swelling of the joints, and almost 
every chronic inflammation. From the superior 
expansibility of the veins, stimulants moderately 
applied in chronic inflammation, may augment 
the calibers of the veins, without affecting the 
diameters of the arteries. By this superior expan- 
sibility of the veins, they are thus enabled to 
draw the blood quickly out of the capillaries, and 
equalize the circulation of the inflamed part with 
the rest of the system. 
coxxxvit. Most commonly, elinemic inflamma- 
tion is preceded by some increase of arterial action ; 
but sometimes it arises wholly from defective venal 
expansibility.. I shall illustrate this position by 
neuralgia of the sacral extremities, a disease of 
extreme interest, and very imperfectly understood. 
ecoxxxvit. Neuralgia.—This disease is caused 
by exposure tocold, at least I have never known a 
case of it arise otherwise. It begins with a numb 
pain extending from the trochanter major along the 
course of the sciatic nerve, as far as the outer 
ankle. Its accession is sometimes so instanta- 
neous, that the patient finds himself incapable of 
walking, without the least previous warning of 
approaching disease. As the muscles waste from 
the commencement of neuralgia, this may be 
