EXAMINATION OF THE ITCH RESPONSE FROM THE RAPHIDES OF THE FISHTAIL PALM CARYOTA-MITIS

The raphides in the mature fruit of the fishtail palm Caryota mitis Lour. were isolated by mechanical separation. These were shown by X-ray crystal analysis to be calcium oxalate monohydrate (Whewellite). The application of an aqueous suspension of the raphides to intact human skin results in an immediate, severe itch sensation. An investigation of this phenomenon appears to indicate that this is due solely to a mechanical action of the calcium oxalate needle and not to the previously postulated action of organic toxins or enzymes introduced through the skin by the penetrating action of the raphides. © 1979.