Menand Molecules 183 upon J. B. Murphy's cancer studies, to be discussed in Chapter 9, ap- parently because he and his assiduous colleague, the physicist. Harry Clark, were using X rays to stimulate and inhibit lymphocyte action in experimental cancer. A new subdivision of the Institute, formally desig- nated as biophysics and opened in 1927 under Ralph W. G. Wyckoff, un- dertook to study the biolugical applications of X-ray crystallography. This was a new method of studying the atomic structure of chemical elements and compounds, developed in 1912 by Max Laue of Berlin and Sir William Bragg of London. It was based on the fact that crystalline materials act as diffraction gratings for X rays by virtue of the regular spacing of their atoms or molecules, exactly as closely ruled lines on a glass plate produce a visible spectrum by diffracting ordinary light. ‘Thus any crystalline substance will defect an X-ray beam passing through it, and produce on a photographic film a regular geometric pattern char- acteristic of the kinds and arrangement of atoms or molecules of which it is composed. Wyckoff was the outstanding American pioneer in the use and refine- ment of this new method of analyzing crystalline substances. He had be- gun work at the Geophysical Laboratory of the Carnegie Institution of Washington in 1919, immediately after taking his Ph.D. at Cornell. His most important carly contribution was to put the determination of crys- tal structures on a rigorous basis by applying the mathematical theory of space groups. Lecomte du Noiiy, Carrel’s brilliant associate at Com- pitene during the war and for a few years thereafter in New York, worked briefly with the young physicist in Washington, When he re- ported that Wyckoff saw a possibility of determining, by X-ray crystallog- raphy, the structure of complex organic substances, even proteins, Flex- ner brought Wyckoff to the Institute as Associate Member in charge of the subdivision of biophysics. It would have been hopelessly difficult to begin with the enormously complicated protein molecule. Since hemoglobin, the iron-containing re- spiratory pigment of red blood cells, was one of the proteins toward which the work was pointed, Wyckoff began studying the ammonium chloro- stannates, salts far simpler than hemoglobin but, like it, containing nitro- gen and complexly bound iron in a highly symmetrical arrangement. With seven X-ray machines already at his command in 1928, Wyckoff added an X-ray spectrometer of his own design and developed a new eee LT RMS 7 182 A HISTORY OF THE ROCKEFELLER INSTITUTE work, he appointed Frederick L. Gates, eldest son of F. T. Gates, presi- dent of the Board of Trustees, who had joined the Institute in 1913 im- mediately after graduating from the Johns Hopkins Medical School. A brilliant student, and very ingenious at devising new methods and ap- paratus, Gates worked at first on bacteriological problems in Flexner’s division, associated with Peter Olitsky in investigations on the bacteriol- ogy of dysentery and of influenza. Flexner now sent him to the Univer- sity of Chicago and Johns Hopkins for a half year to prepare for work on photobiology. To collaborate with Gates on the chemical side, he ap- pointed Oskar Baudisch, a European-trained specialist in photochemical synthesis, and Lars A. Welo. Gates began at once to study ultraviolet light, known to be the effec- tive portion of the solar spectrum in the light treatment of rickets, al- though the nature of its beneficial action was quite unknown. To sim- plify the problem, Gates used bacteria as the living material in his earliest experiments. With the aid of accurate thermocouples of his own design for measuring energies available at different wave-lengths, he worked out the action spectra—the relation between various wave- lengths of ultraviolet light and their action, stimulating or destructive according to the circumstances, upon bacteria, bacteriophages, viruses, and enzymes. The little group Flexner had tentatively organized did not fuse into an effective unit. Baudisch and Welo worked on quite different prob- lems, and Gates’s studies were too new to make much impression at the time. Because of an obscure illness, which caused his untimely death a few years later, it was thought he might profit by a change of scene, and he transferred his laboratory to Harvard University in 1929. His work at the Institute on the action spectra of ultraviolet light, continued at Cambridge, was the first definitive study of the subject, and biophysicists now recognize Gates as a pioneer in this field.?8 When in 1936 Northrop made his remarkable discovery that a bacteriophage, regarded as a living biological agent, could be isolated as a chemical substance of protein nature, Gates’s determination of the wave-lengths of ultraviolet light which are destructive to bacteriophage served as evidence that North- rop’s protein and that of the bacteriophage were identical. The work which Flexner had called photobiology fully deserved the title of biophysics, but that name had some years before been conferred Menand Molecules 183 upon J. B. Murphy's cancer studies, to be discussed in Chapter 9, ap- parently because he and his assiduous colleague, the physicist Harry Clark, were using X rays to stimulate and inhibit lymphocyte action in experimental cancer. A new subdivision of the Institute, formally desig- nated as biophysics and opened in 1927 under Ralph W. G. Wyckoff, un- dertook to study the biological applications of X-ray crystallography. This was a new method of studying the atomic structure of chemical elements and compounds, developed in 1912 by Max Laue of Berlin and Sir William Bragg of London. It was based on the fact that crystalline materials act as diffraction gratings for X rays by virtue of the regular spacing of their atoms or molecules, exactly as closely ruled lines on a glass plate produce a visible spectrum by diffracting ordinary light. Thus any crystalline substance will deflect an X-ray beam passing through it, and produce on a photographic film a regular geometric pattern char- acteristic of the kinds and arrangement of atoms or molecules of which it is composed. Wyckoff was the outstanding American pioneer in the use and refine- ment of this new method of analyzing crystalline substances. He had be- gun work at the Geophysical Laboratory of the Carnegie Institution of Washington in 1919, immediately after taking his Ph.D. at Cornell. His most important early contribution was to put the determination of crys- tal structures on a rigorous basis by applying the mathematical theory of space groups. Lecomte du Noiiy, Carrel’s brilliant associate at Com- piégne during the war and for a few years thereafter in New York, worked briefly with the young physicist in Washington. When he re- ported that Wyckoff saw a possibility of determining, by X-ray crystallog- raphy, the structure of complex organic substances, even proteins, Flex- ner brought Wyckoff to the Institute as Associate Member in charge of the subdivision of biophysics. It would have been hopelessly difficult to begin with the enormously complicated protein molecule. Since hemoglobin, the iron-containing re- spiratory pigment of red blood cells, was one of the proteins toward which the work was pointed, Wyckoff began studying the ammonium chloro- stannates, salts far simpler than hemoglobin but, like it, containing nitro- gen and complexly bound iron in a highly symmetrical arrangement. With seven X-ray machines already at his command in 1928, Wyckoff added an X-ray spectrometer of his own design and developed a new xi