Edinburgh Royal Society, Edinburgh, June 7, 1937. H. S. TAYLOB: Heavy hydrogen in scientific research (Bruce-Preller Lecture). Heavy hydrogen has led to interesting developments in theoretical and experimental aspects of reaction kinetics, especially in the fields of catalysis and photochemistry. Problems of molecular structure involving all types of spectral analyses of deuterium-containing compounds have also been solved. The biological and astronomical aspects of the problem were discussed, and the important role of deuterons, at high voltages, in the production of artificially radioactive elements and isotopes of known elements, particularly in the field of radiotherapy, was indicated.