Document DD4kgGMB4kD8QQkRNzJpRkj1d

August 19, 1960 Dr. Alfredo Pavlovsky Junia 1284 Buenos Aires Argentina Dear Doctor Pavlovsky: I am sending herewith the two reports on various aspects of the problem of tetramethyl lead. As I told you when you visited us, we are carrying opt some fairly extensive investigations on the toxicity of this material in step-by-step comparison with that of tetraethyl lead. I have given out little but preliminary information on this subject until we have cleared up some matters of fact by elucidating the effects of fairly prolonged exposure of animals to low concentrations. The only general statements I care to make at this time are (1) that tetramethyl lead is much less rapidly absorbed through the skin than is tetraethyl lead; (2) that tetramethyl lead is less toxic than tetraethyl lead after it has been absorbed; and (3) that tetramethyl lead is more stable (less readily decomposed, chemically) in the body of an animal than is tetraethyl lead. These facts are important qualitatively, but the question which I cannot answer now concerns the extent to which they are important quantitatively, You will hear further from us on this subj ect. It V.'ias a pleasure to have you here, and I hope you will find it possible to visi t us soon again. Sincerely yours, Robert A. Kehoe, M. D. RAK:ss Enel: 2 Reports - Tetramethyl Lead Lead Alkyls