WE have already advanced some evidence that sterculic acid is o-(2-n-hexylcyclopropyl)dec-9-enoic acid. Support for this assignment has been obtained by potassium permanganate oxidation of the acid. Production of hexyl %-methyl ketone, heptanoic acid, and azelaic acid may be explained on the basis of our formulation but not on the cyclopropene structure assigned by Nunn.2 The same products were obtained by Hilditch, O'Meara, and Zaky 3 from permanganate oxidation of the total fatty acids of Sterculia fcetida oil.ExperimentaE.-Sterculic acid (6-2 g.), in dry acetone (98 ml.), was refluxed with powdered potassium permanganate (25 g . ) for 1 hr. The solvent was then removed, and the residue suspended in water and saturated with sulphur dioxide. The mixture was then steamdistilled, the distillate neutralised with sodium carbonate and extracted with ether, the ethereal extract dried (Na,SO,j, and the solvent removed. The neutral product (0.5 g.), b. p. 169-173' (Found : C, 74.5; H, 12-3. Calc. for C,H,,O : C, 74.9; H, 12.6%), formed a 2 : 4-dinitrophenylhydrazone, m. p. 59" not depressed when mixed with n-hexyl methyl ketone dinitrophenylhydrazone (Found : N, 18.6.The alkaline solution, left after ether extraction, was acidified and extracted with ether, the extract dried (Na,SO,), and the solvent removed, yielding a liquid (1.8 g . ) , b. p. 220°, nt7 1.4219