Vi . CONTENTS 



Paper Page 



XXIX. Effects of X-rays upon Green Plants 961 



Edna L. Johnson, Associate Professor of Biology, University of 

 Colorado, Boulder 



XXX. The Effects of Radium Rays on Plants 987 



C. Stuart Gager, Director, Brooklyn Botanic Garden, Brooklyn 



XXXI. The Light Factor in Photosynthesis 1015 



H. A. Spoehry Chairman, Division of Plant Biology, Carnegie Insti- 

 tution of Washington, Stanford Universitj^ California 

 J. H. C. Smith, StafT Member, Division of Plant Biology, Carnegie 

 Institution of Washington, Stanford University, California 



XXXII. The Influence of Radiation on Plant Respiration and Fer- 

 mentation 1059 



Charles J. Lyon, Professor of Botany, Dartmouth College, Hanover, 

 N.H. 



XXXIII. Growth Movements in Relation TO Radiation 1073 



Earl S. Johnston, Assistant Director, Division of Radiation and 

 Organisms, Smithsonian Institution, Washington, D.C. 



XXXIV. Chlorophyll and Chlorophyll Development in Relation to 



Radiation 1093 



O. L. Inrnan, Director, Kettering Foundation for the Study of 

 Chlorophyll and Photosynthesis, Antioch College, Yellow Springs, 

 Ohio 



Paul Rothemund, Research Chemist, Kettering Foundation for 

 the Study of Chlorophyll and Photosynthesis, Antioch College, 

 Yellow Springs, Ohio 

 C. F. Kettering, Director of Research, General Motors Corporation 



XXXV. Radiation and Anthocyanin Pigments 1109 



John M. Arthur {see Paper XX) 



XXXVI. Effects OF Radiation ON Bacteria 1119 



B. M. Duggar, Professor of Plant Physiology and Applied Botany, 

 University of Wisconsin, Madison 



XXXVII. The Effects OF Radiation ON Enzymes 1151 



Harold A. Schomer, Fellow in Botany, University of Wisconsin, 

 Madison 



XXXVIII. Induced Chromosomal Aberrations in Animals 1167 



Theodosius Dobzhansky, Assistant Professor of Genetics, California 

 Institute of Technology, Pasadena 



XXXIX. Radiation and the Study of Mutation in Animals 1209 



Jack Schultz, Research Assistant, Carnegie Institution of Washing- 

 ton, California Institute of Technology, Pasadena 



