1. Adrenal bodies have been shown to be present on the anterior or ventral surface of the kidneys of Xenopus . Extracts of this region of the kidney contain a sympathomimetic substance, probably adrenaline. 2. Active preparations are best obtained by extracting freshly excised kidneys with normal saline solution. The extracts should be used immediately. 3. Amphibian tissues appear to react more sensitively than mammalian tissues towards the extracts.