Perspectives in Biology and Medicine

A CURIOUS KIND OF DISTANT REFERRAL FROM A SLIGHTLY PAINFUL STIMULUS TO THE SKIN WILLIAM B. BEAN* For almost as far back as I can remember I have noticed an occasional double reference of sensation from a slight scratch, irritation, or pin or thorn prick of the skin. Observant persons are aware of sensations perceived as coming from a distance from a recognized stimulus. When the ulna is struck at the elbow on the crazy bone or funny bone it sends a message of pins and needles that seems to be coming from the little and ring fingers. That referral is easy to understand since a nerve stimulated along its course has to send its one and only message along a pathway which is interpreted as coming from its distal sensory receptor. Put a spoonful of ice cream or ice under the tongue and a pain is felt in the forehead. Suddenly going out into the sunshine may send a tickle to our nose and make us sneeze. Sherrington believed that the reaction to sudden light was not between the optic nerve and nasal branches of the trigeminal nerve but involved the branches of the trigeminal nerves supplying the eyeball and those supplying the nose [I]. Indeed, according to Sherrington, Mitempfindung, sympathetic or associate sensations, had been observed by Johann Müller and many others. Sherrington found that applying mustard over his sternum could give rise to a sensation of heat and unpleasant tingling on the inner side of each armjust above the condoyle. He said "during the phenomenon I cannot rid myself of the belief that the skin there must be looking red, but no flush is found. In this case the associated sensations and the stimulus applied lie, as shown by delimitations of the cutaneous segmental-nerve areas, both of them within the same segemental area." When I was a child, I noticed an occasional double sensation from some minor irritation, scratch, pinprick, picking at a single hair follicle, or some minor stimulus where touch merges into mild pain. Though the An earlier version of this paper was presented at Castle Harbor in Bermuda on October 24, 1979, at the 94th Meeting of the American Clinical and Climatological Association, published in vol. 91 of their Transactions by the Waverly Press, 1980, pp. 147-157. *Institute for the Medical Humanities and the Department of Internal Medicine, University Hospitals, Iowa City, Iowa 52240.© 1981 by The University of Chicago. 003 1-5982/81/2403-0145$01.00 440 I WilliamB. Bean ¦ ReferralfromDistantStimuli usual sensation is felt at the exact spot where the stimulus is received, there is, simultaneously, a gentle tingling, slightly painful sensation at a different, distant point, as though a tiny electrode has discharged. I asked my father, who was professor of anatomy at the University of Virginia, about this. He could make no sense ofit and had never heard ofit. Neither ofus could see anything unusual, such as a flush, goose pimples, pallor, or anything in the area of referral. I asked about it no more. At irregular intervals I recorded the primary stimulus point and the referral site on simple, two-dimensional charts which I had used for many years to record such things as the distribution and size of vascular spiders or skin lesions in pellagra. I never set about making a systematic analysis of my own responses for the curious reason that as one is concentrating and attending to the phenomenon it seems to suppress it or make it disappear. The reaction is characteristically noted when one is thinking of something else, daydreaming, or in a state of detachment, not concentrating on anything in particular. Once the stimulus is applied, repetition usually extinguishes the sensation of referral. A few times when I have been lightly scratching a trivial itch about once per second the sensation of referral occurred two to four times and then vanished. The position of the body or limb seems to make no difference. I made a few records when our three children were in grammar school and they noticed such double sensations. My wife has never experienced them. I began keeping charts of these observations inJanuary of 1953 when I...