1.2. In the late eighteenth and early nineteenth centuries, chemical experimentation led ultimately to its use in the discovery of new drugs In 1853, Henry How conceived the idea that functional groups in natural products might be modified by chemical reagents He heated morphine with methy iodide, hoping to convert the alkaloid to codeine. He obtained however a new substance of the quaternary salt of morphine OH• 1.2. In the late eighteenth and early nineteenth centuries, chemical experimentation led ultimately to its use in the discovery of new drugs. • In 1853, Henry How conceived the idea that functional groups in natural products might be modified by chemical reagents. He heated morphine with methyl iodide, hoping to convert the alkaloid to codeine. He obtained, however, a new substance of the quaternary salt of morphine. HO O H OH N