To the Editor:—
Doctor Goldwater's points are well taken. The vehicle must be taken into account, and in the usual commercial preparation of the esters of 2,4-D the vehicle is usually a petroleum solvent plus an emulsifier, but these are usually listed as inert ingredients by the manufacturer. Dr. R. B. Hurl of Marysville, Ohio, wrote to us and raised the question about the possible role of the petroleum solvent and the emulsifier in the causation of the peripheral neuropathy. Dr. Hurl suggested that "perhaps it is safer to say that certain proprietary ester formulations of 2,4-D have caused peripheral neuropathy." We agree with this point of view, since the essential point of our article was that undue exposure to a commercial preparation of an ester of 2,4-D was followed by peripheral neuropathy. In one instance we were able to obtain the label from the container of the 2,4-D preparation.