1. The formula of alstonine has been definitely checked as C21H20N2O8. 2. From the products of alkali fusion of alstonine and tetrahydroalstonine, barman, norharman, indole-α-carboxylic acid, and three bases of undetermined structure, probably β-carboline derivatives, have been obtained. 3. Thermal decomposition of alstonine leads to the formation of three bases of undetermined structure, but which are apparently β-carboline derivatives. 4. Reduction of tetrahydroalstonine with sodium and butyl alcohol leads to a new base, hexahydroalstonol, C20H26N2O2, the absorption curve for which is identical with that of yohimbine and α,β-dimethylindole. 5. 1-Ethyl-3-carboline and 3-ethyl-β-isocarboline have been prepared. 6. A partial structure for alstonine is discussed. © 1942, American Chemical Society. All rights reserved.