Speculation in food, Washington, D.C. Sept. 29. When the provisions of the Commodity Exchange Act of 1936 took effect last week, the responsibility for their enforcement was put in the hands of Dr. J.W.T. Duvel, who for eleven years has administered the preceding legislation, the Grain Futures Act. Born in Ohio in 1873 Dr. Duvel was associated with the Food Administration in that agency's New York office