BARKS of various species of Alstonia have been examined in the hope of finding a source of echitamine richer in that alkaloid than is the bark of A. congensis, with a view to determine its constitution. Although the desired end has not been attained, it is thought worth while to record the figures obtained and to present further data on the alkaloids and lactones of the barks of A. congensis, A. scholaris, and A. angustiloba. Unfortunately, a specimen of the bark of A. spectabilis, R.Br., which Hesse (Annalen, 1880, 203, 170) states contains 0.808% of echitamine, an amount far in excess of that in any other species examined, was not available. A new crystalline alkaloid, C20H26O3N2, which it is proposed to call echitamidine, has been obtained in small quantities from the mother-liquors from echitamine hydrochloride from the barks of A. congensis and A. scholaris, and crystalline salts prepared. Two crystalline lactones of the formula C9H14O3, one (called "lactone C") identical with that isolated from the bark of A. congensis (J., 1927, 127, 1647) and which also occurs in the bark of A. angustiloba, have been isolated from the bark of A. scholaris; the second lactone is called "lactone S." The view that echitamine is a methyl ester, which is hydrolyzed with great ease (ibid., p. 1646), has been confirmed, and a ready means of preparing demethylechitamine found by boiling a solution of echitamine to which an equivalent of sodium hydroxide has been added: the methyl alcohol produced in the hydrolysis was identified as p-nitrobenzoate. The instability of echitamine base in aqueous solution is in marked contrast to the stability of echitamine salts, which suffer very little change when their solutions are boiled, and explains the production of demethylechitamine in attempts to crystallize echitamine base from solutions containing water. Demethylechitamine has been reconverted into echitamine hydriodide by boiling it with methyl iodide, and into echitamine methyl sulphate by the action of methyl sulphate in the cold. When an equivalent of sodium methoxide in methyl alcohol was added to echitamine hydrochloride in an attempt to prepare crystalline echitamine base, the acicular crystals of echitamine hydrochloride gave place to rhombic prisms consisting of a compound of the hydrochloride and methyl alcohol. It was subsequently found that the presence of sodium methoxide was not necessary for the formation of this substance. Ethyl alcohol does not form a similar compound. Several of these barks have not been examined previously, and with the exception of A. scholaris, none of them is readily accessible. The author is therefore greatly indebted to the Authorities of the Imperial Institute; The Director of the Royal Botanic Gardens, Kew; Mr. A. R. Penfold, Curator of the Technological Museum, Sydney; Mr. C. F. White, Government Botanist, Brisbane, Queensland; and Dr. A. F. Fischer, Director of Forestry, Manila, Philippine Islands, for their kindness in providing the samples used in this investigation.