RELIEF OF PAIN. 449 



Weber's explanation of stasis as anything more than an hypo- 

 thesis ; but, as I have ah'eady said, I am inclined to adopt it, 

 and to consider that inflammation begins in vertebrates when 

 coagulation occurs in the capillaries, and arrests the flow of 

 blood through them. 



But whether tliis view be taken or not, the facts are certain, 

 that stoppage of the circulation does occur in the irritated capil- 

 laries, and that the arteries leading to the part are dilated. 

 What the cause of the pain in inflammation is, we do not 

 exactly know ; but it seems very probable that it depends to a 

 great extent on the stretching of the vessels, and the nerves 

 surroundhig them, at or near the site of stasis, by the blood 

 which is driven into them through the dilated arteries. For, 

 as every one knows, the pain of inflammation is of a throbbing 

 character ; it is increased at each time the vessel is distended 

 by a beat of the heart, and relieved by lessening the supply of 

 blood. ISTow, the supply of blood can be lessened in several 

 ways, and several means, apparently of an entirely opposite 

 nature, are used to relieve pain. Supposing that w^e take as an 

 example an inflammation of the tip of the finger, it is easy to 

 understand how it may be relieved by pressure on the radial 

 artery, or by raising the hand to the level of the shoulder, and 

 may be aggravated by allowing the arm to hang dependent by 

 the side. But how is it that the pain in the finger may be 

 relieved by dipping it in cold water, and also by the application 

 of a warm poultice ? I believe the answer to this question to 

 be that the cold causes the arteries above the point of stasis 

 (Fig. 157) to contract — and thus lessens the force of the 

 current of blood which is being pumped upon that point. The 

 warm poultice, on the other hand, dilates those capillaries in 

 which circulation is still going on, and by thus offering another 

 channel to the blood, lessens the force of the current against the 

 point of stasis. It is well known, too, that the pain of a burn 

 can be greatly lessened by holding the burnt part before a fire. 

 But, as I can testify from personal experience, the pain is first 

 greatly increased before it is relieved. I placed a red-hot coal 

 on the back of my hand until the skin was corrugated and 

 glazed. I then held it before a brisk fire for some time. At 



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