In a recent patent, Eagleson (1) described the use of sesame oil as a "synergist" or "activator" when combined with insecticides containing pyrethrins, rotenone, and the like. The addition of sesame oil reduces the concentration of the insecticide required to give 100% mortality of houseflies, and prolongs the paralysis or torpor of such insects as are not killed by the spray. For example, Eagleson found that a pyrethrum insecticide containing a 0.001 molar concentration of pyrethrins in refined kerosene, when sprayed on houseflies in the appara-TABLE I Effectiveness Against Houseflies of Various Fractions of Sesame Oil, Alone or As an Adjunct of Pyrethrum in Refined Kerosene (Two tests of about 150 flies each; concentration of pyrethrins 1 mg. and of sesame oil and its fractions 10 mg. per cc.

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A recent discussion of the role of the solvent in acid-base equilibria was given by Hall' at the Cincinnati symposium on non-aqueous solutions. Opinion regarding the solvent influence on the physical properties of the solute may be divided into two divergent schools. The summary of Bronsted2 would indicate that the solvent influence is a constant and additive factor a t least for acids and bases in alcoholic solution, C~n a n t ,~ however, considers that the simplest relationships between the structures of compounds and the free energy changes of their reactions will be found in the gaseous state.It is apparent that an attempt to compare the relative affinities of organic radicals by measuring the electrical properties of polar groupings attached to these radicals cannot be successful if the solvent influence on the free energies of the polar groupings is erratic, As previously stated,4 it would be expected that the variations in the electrical properties of any polar grouping could be expressed as it. function of the electron-sharing ability of the organic radical attached to it. If the polar grouping formed a complex with the solvent, this complex would be expected to be of a characteristic structural type for that particular polar grouping and solvent. The free energy of the polar grouping with its solvent complex would still be a function of the electron-sharing ability of the organic radical, since this is the only variable factor affecting the polar grouping. Erratic or irregular influences due to the solvent would be expected only if the radical contained atoms other than the polar grouping which united with the solvent. If these latter complexes did not themselves dissociate to form electrically charged bodies which would interfere with the measurements for the polar grouping, disturbing influences would be expected only if the second union were located with but four5 or less atoms between it and the polar grouping. (1) Hall, C h m . Rcu., 6, 191 (1932). (2) Bransted, ibid., 6, 291 (1928). (3) Conant, Ind. Eng. Cham., 94,466 (1932). (4) Hixon and Johnis, THIS JOURNAL, 49, 1788 (1927).(5) This statement is based on the fact that the inhence of the most negative radicals seems to be abaorbed completely before ttensmisnion through four carbon atoms.

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The ,/3-hexenoic acid (m. p. 33-34°) gives with silver chlorate the dl-1,2-dihydroxycaproic acid (m. p. 108.5°) with 86% yield and with perbenzoic acid the df-l,2-dihydroxycaproic acid (m. p. 99.5°) with 46% yield. Chicago, Illinois