 Louis Lasagna, then a prominent clinical pharmacologist at the Johns Hopkins School of Medicine, advised Congress about the proper conduct of clinical research during the 1962 hearings leading up to passage of the Amendment.The law also exempted from the "Delaney clause" (a 1958 amendment to the Food, Drugs, and Cosmetic Act of 1938) certain animal drugs and animal feed additives shown to induce cancer, but which left no detectable levels of residue in the human food supply.Sources