The search for anti-malarial drugs in the genus Alstonia was continued by examining four more species: A. somersetensis, A. verticillosa, A. villosa, and A. macrophylla. A. verticillosa contains a considerable amount of a mixture of sterols and a small amount of echitamine, very similar to A. scholaris. The other three barks all contain, in addition to much amorphous base, an alkaloid which forms well-defined crystalline salts and for which the name villalstonine is suggested as it was first isolated from A. villosa. A. macrophylla contains, besides villalstonine, three other alkaloids: macralstonine, macralstonidine, and base M (present in exiguous amount). Macralstonidine is also present in A. somersetensis, and a new base V has been obtained from A. villosa. Villalstonine, C₄₀H₅₀O₄N₄, has two basic and two non-basic nitrogen atoms, one methoxy- and two methylimino-groups, with its more complex formula confirmed by molecular-weight determination cryoscopically in benzene; hydrolysis with alcoholic potassium hydroxide furnishes an amphoteric substance without a methoxy-group. Macralstonine, C₃₇H₄₂O₄N₄, is crystalline, forms a crystalline sulphate, and has opposite optical rotation signs for the base and sulphate. Macralstonidine, C₄₁H₅₂O₄N₄, contains two methylimino-groups and appears to have a dioxymethylene group. Bases M and V are crystalline but in too small amounts to determine their formulae. All new alkaloids are indole derivatives. Pharmacological experiments with villalstonine hydrochloride showed a slight increase in isolated rabbit uterus movement at 1:6,500-1:12,500, a fall in anesthetized cat blood pressure (less than alstonine sulphate), no action on guinea-pig uterus (1:25,000) or rabbit intestine (1:50,000); its action on bird malaria was undetermined. Alstonia alkaloids fall into three groups: (a) echitamine (many species from Africa, East Indies, Australia), (b) villalstonine (Australian and East Indian species), (c) alstonine (only A. constricta from Australia).