Cephalotoxin: the Crab-paralysing Agent of the Posterior Salivary Glands of Cephalopods

Abstract

THE presence of a substance, toxic to crabs, in the posterior salivary glands of cephalopods (Giftdrusen of the German authors) has been known for a long time¹. When a drop of saliva collected from Octopus is injected into a crab, a sequence of reactions is observed followed by complete paralysis of the animal². Active substances have been extracted from the posterior salivary glands of octopuses³, and their presence has been demonstrated in external and internal secretions⁴. Most of these substances have a powerful action on crabs and upon isolated organs of molluscs and other invertebrates⁵. Tyramine, the substance first isolated from the glands by Henze⁶, was, and still is, believed to be the toxic agent⁷. However, none of the extractive substances found in the posterior salivary glands of cephalopods, even tyramine, can reproduce the paralysing action of the crude extracts or of saliva. The observations of Livon and Briot⁸, recently confirmed by me⁹, claim a more complex composition. The active principle is inactivated by heating, does not pass through dialysing membranes and can be purified by precipitation with ammonium sulphate.