The Water-balance Principle of Crustacean Eye-stalk Extracts

Abstract

IT has long been known¹ that extracts of crustacean eye-stalks contain a principle which not only influences the colour changes of crustaceans but also induces expansion of the melanophores in amphibians, acting in this respect like the intermediate lobe pituitary hormone. It was therefore of considerable interest when Gray and Ford² reported that extracts of crustacean eye-stalks produce an increase of water uptake in frogs similar to that observed after the injection of neurohypophysial extracts. No structure homologous to the vertebrate neurohypophysis has so far been identified in invertebrates ; but the results of the American authors suggest the possibility that crustaceans, although they have no pituitary gland, elaborate pituitary-like hormones.