Available evidence suggeststhat the sensa-tion of itching is closely related to that ofpain (1). Titchener (2) observed that when the skin was explored with a fine hair, well-defined points were found which gave rise to itching when the in-tensity of stimulation was low, andto pain on stronger stimulation. Bishop (3) found that itch-ing resulted from repetitive low intensity electrical stimulation of pain spots in the skin. Lewis, Grant and Marvin (4) pointed out that noxious stimuli, if their intensity be decreased, can be made to produce itching instead of pain. Forster (5) and Bickford (6) reported that in patients who had undergone section of the lateral spinothalamic tracts, thus abolishing perception of cutaneous pain but not of touch, itch was alsoabolished. Bickford also observed this combination of sensory changes in two patients with syringomyelia. Ehrenwald and K6nigstein (7), however, stated that they had found two cases of syringomyelia with loss of pain but preservation of touch and itch, and one in which pain was intact but touch and itch absent. McMurray (8) and Kunkle and Chapman (9) found that individuals who were constitutionally insensitive to pain were likewise insensitive to itching, but they experienced touch sensation. Bickford observed that itching and pain disappeared at the same time when a cutaneous nerve was anesthetized. Hardy, Wolff and Goodell (10) observed that in addition to feel-ings of warmth, occasional itching resulted from sustained thermal irradiation at an intensity not quite strong enough to induce pain. Th6le (11) found during spinal anaesthesia, as the sensitivity of the skin to painful stimuli decreased, that stimuli which initially induced pain later induced itching and finally no sensation at all. In the present investigation many of the ex-periments described by Goldscheider (12), Bick-ford, and Lewis and associates have been repeated. Additional experiments were designed to illumi-37 nate further the neural mechanisms involved in itch," itchy skin" and tickle sensation.