Mysterious form of referred sensation in man.

A phenomenon is described in which scratching a small excrescence on the skin on one part of the body is referred to a distant point as a "prick" or a "tingle". "Referral" points are elicited mainly by absent-minded scratching of the skin when attention is not focused on the local sensation produced by the scratch. Location of "referral" points seems to follow definite patterns: in all instances, "referral" points occurred on the same side of the body as the "stimulus" point; and each "referral" point was rostral to its "stimulus" point; and each "stimulus" point was associated with only one "referral" point. "Stimulus" and "referral" points seem to have a fixed relationship. Pathways from a "stimulus" point to a "referral" point are not known at present. Although parallels can be drawn between this phenomenon and Bender's "double simultaneous stimulation" phenomenon, both remain mysteries.