an uneasy sensation, arising from a sudden and violent solution of continuity, or other accident in the nerves, membranes, vessels, muscles, &c. of the body. Pain, according to some, consists in a motion of the organs of sense; and, according to others, it is an emotion of the soul occasioned by those organs.
As the brain is the seat of sensation, so it is of pain. Boerhaave, and most other authors on this subject, assign a stretching of the nerves as the only immediate cause of pain: but as the nerves do not appear to consist of fibres, this cause of pain does not seem to be well-founded; nor indeed will it be easy to treat this subject clearly, but in proportion as the means of sensation are understood.
Many kinds of pain are met with in authors: such as, A gravitative pain; in which there is a sense of weight on the part affected, which is always some fleshly part, as the liver, &c. A pulsative pain; which, Galen says, always succeeds some remarkable inflammation in the containing parts, and is observed in abscesses while suppurating. A tensive pain, which is also called a distending pain; it is excited by the distension of some nervous, muscular, or membranous part, either from some humour, or from flatulence. An acute pain is, when great pain is attended with quick and lively sensations: A dull pain is, when a kind of numbness is as much complained of as the pain is.
The mediate and more remote causes of pain are generally obvious; and when this is the case, the cure will consist for the most part in removing them: for though in many instances the chief complaint is very distant from the seat of those causes, yet their removal is the proper method of relief. See MEDICINE, passim.
Perhaps all pains may be included, with irritation, in those that have spasm or inflammation for their source. When pain is owing to inflammation, the pulse is quicker than in a natural state; it is also generally full, hard, and tense; the pain is equal, throbbing, and unmitting. If a spasm be the cause, the pulse is rarely affected; at intervals the pain abates, and then returns with some degree of aggravation; gentle motion sometimes abates, or even cures, in some instances; but in inflammatory cases no such effects are ever experienced. See Dr Lobb's Treatise on Painful Distempers.
The pain so frequently attendant on women in childbed, called after-pains (from their happening only after being delivered of a child), are often occasioned by attempts to bring away coagulated blood, which is a needless endeavour. When no improper treatment in delivering the secondines can be suspected, the irritability of the uterus alone is to be considered as the cause. Care should be taken not to confound these after-pains with, or mistake the pains attending puerperal fevers for the colic. After-pains come by fits, and soon go off; but return at different intervals, which are longer each day, and after two or three days are usually at an end, though sometimes they continue seven or eight: notwithstanding these pains, the lochia flow properly, and generally more abundantly after the cessation of each fit; this does not happen in colicky complaints, nor is the belly so free from tumefaction when the puerperal fever is attendant.
As these pains are of the spasmodic kind, anodynes