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T H E JO U R N A L O F IN D U ST R IA L H YG IEN E A N D T O XIC O LO G Y HARVARD SCHOOL OF PUBLIC HEALTH ^Managing Editors Ph il ip .Dr in k e r M a r g a r e t S.

ETHYL CORPORATION RESEARCH LABORATORIES 1600 WEST EIGHT MILE ROAD EERNDALE 20 DETROIT, MICHIGAN cc : Mr.

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TH E JOURNAL OF INDUSTRIAL H YGIENE AND TOXICOLOGY HARVARD SCHOOL OF PUBLIC H EALTH t,M anaging editors Philip Drinker Margaret S.

ROOM 1815 LETTER!

Philadelphia, Pa., June 25, 1?

Philadelphia, Pa*, June 19, 1944.

Philadelphia, Fa.