PAIN (1)1'.. Fr. pine. from 1\1L. prima. Lat. pa-na. pain, punishment. from Gk. 7rotvh, penalty; connected with Gk. rimy, finely. to pay, skt. ri. to avenge). A term employod by the English assOc-iationist school (see .‘,()CIATI(1N or IDEA, for what we haxe termed unpleasantness (see AFFECTION ) , pleas ure and pain being the two fundamental quali ties of the affective life. But the concrete pains of everyday experience are, as even a superficial introspection shows, partly matters of sensation. ''Pain (8chmerz) is always at once a sensation and a violent feeling of unpleasantness (rn lustycfuhl)'' (Wundt). it is therefore impos sible to restrict the term to the sphere of af fection.
the heading Cc TANEcus SENSATIONS, it is noted that pain is. as a matter of fact, a dis tinct and specific cutaneous quality, having as its terminal organs the free nerve endings in the epidermis. The pain spots are constant in position, and min-mapg c•an lie drawn which furnish as permanent and valid records of the pain sensitivity as do the pressure and temperature maps of their cutaneous qualities. We have here, then, merely to dis cuss pain as an organic sensation It was formerly supposed that pain was a common sensation, ex citable by excessive stimulation of any and every sensory nerve, optic, acoustic, etc. This theory still lingers in the belief. e.g. that there are special temperattire pains pro ducible and only producible by ex cessive thermal stimulation of the cutaneous s u r f a c e.
But it found its chief support in the great variety of organic pains. There seems to lie no internal organ, however insensitive during healthy func tion, that cannot me diate pain when the function is deranged. And the pains vary in character, according to their place or mode of origin. They may he throbbing, as in toothache; dull and gnawing, as in ex treme hunger or in inflammation of the bowels; d 11 11 and throbbing, as in lesion of the rectum; acute and shooting, as in neuralgia; acute and intermittent, as in colic; acute and constant. as in peritonitis;
dull and nauseating, as in certain diseases of the ovaries and testicles; pressing, boring, constricting, cut ting. piercing, as in headaches; burn ing or smarting, as in certain skin dragging, as in certain forms of rheu matism. It is very natural—indeed, it seems at first sight necessary—to explain these differences as differences of quality; to assume the existence of many- different kinds of pain. If we look at the facts more closely, however, we see that certain of the descriptive adjectives point unmistakably to simple differences of time and of intensity. A throbbing pain is an interrupted pain; a shoot ing pain is one that shows, besides intermittence, a quick rise of intensity as it runs its course; a piercing pain is intensive, a dull pain weaker. Moreover, all the concrete pains are intermixed with the specific sensations (pressure, various organic qualities) peculiar to the organs which mediate them: a sickening pain contains the sensation of nausea, a dragging pain contains a mass of muscular sensations. These concomi tant sensations, again, are variously localized: an acute pain seems to occupy a small area, a (lull pain is massive, wide-spread. When we take these facts into account, and remember the specific differences to which variations of time and intensity may give rise in conscious com plexes other than pains, we shall hardly resist the conclusion (suggested also by introspection) that the pain quality is one and the same throughout. There is one pain; there are many pains. The many pains differ temporally, in tensively, and in their associations; not quali tatively. The organ of this organic pain quality must then be looked for in the muscle substance; but whether it consists of a free nerve-ending, like the pain-ending of the epidermis, we do not know. Consult: Titchener, Experimental Pswehol ogy (New York, 1901) ; Windt, Physiologisehe Psychologic (Leipzig, 1893).