dextro-Tubocurarine chloride was first isolated in crystalline form from native tube-curare1. It has since become a valuable adjunct in anaesthesia2. The chemical constitution of dextro-tubocurine chloride and its relation to bebeerine3 suggests that its botanical origin lies in some species of Chondrodendron. Through the kindness of Mr. J. W. Massey, British consul in Iquitos, the stem and leaves of Chondrodendron tomentosum Ruiz and Pavon, collected by the late Guillermo Klug at Tarapoto in Peru, have been made available. The leaves were identified by Mr. N. Y. Sandwith of the Herbarium, Kew, as belonging to this species, and on chemical examination the stems yielded l"vo-curine (l-bebeerine) and l"vo-tubocurarine chloride. The latter was found by Dr. B. D. Burns to have a curare action on the rat's diaphragm, which was very weak when compared with that of dextro-tubocurarine chloride.