EXPERIMENTAL STUDY OF ITCH STIMULI IN ANIMALS

Abstract

THIS the use of animals for the investigation of pruritus. Except in the work of Sherrington,¹ animals have not been used hitherto for studies of pruritus. The sparsity of suitable reagents for the induction in animals of an itch paroxysm comparable to that which occurs in man partly accounts for this situation. Even Sherrington's experiments do not relate to the present study directly as they were concerned with the immediate scratch reflex of the dog to a cutaneous stimulus, whereas this work² deals with a sustained type of itch paroxysm which tends to fluctuate in intensity between peaks separated by periods of exhaustion. Recent observations have made it possible to use animals for experiments with pruritus. Richet³ obtained from the tentacles of actinia an aqueous alcohol extract which he termed thalassin. This elicits severe itching in dogs when it is administered intravenously. A treated animal scratches mainly