viii CONTENTS 



Paper Page 



X. The Effects of Irradiation on Venoms, Toxins, Antibodies, 



AND Related Substances 341 



S. C. Brooks, Professor of Zoology, University of California, 

 Berkeley 



XI. The Effects of Radium and X-rays on Embryonic Develop- 

 ment 389 



Elmer G. Butler, Associate Professor of Biology, Princeton Uni- 

 versity, Princeton 



XII. Effects of X-rays and Radium upon Regeneration 411 



W. C. Curtis, Professor of Zoology, University of Missouri, Columbia 



XIII. The Biological Effectiveness of X-ray Wave-lengths. . . . 459 

 Charles Packard, Assistant Professor of Zoology, Institute of Cancer 

 Research, Columbia University, New York City 



XIV. The Physiological Effects of Radiation upon Organ and 



Body Systems 473 



Stafford L. Warren, M.D., Associate Professor of Medicine in charge 



of Division of Radiology, University of Rochester, School of Medi- 

 cine and Dentistry, Strong Memorial Hospital, Rochester 



XV. Short Electric Wave Radiation in Biology 541 



G. Murray McKinley, Instructor in Zoology, University of Pitts- 

 burgh, Pittsburgh 



XVI. Biological Effects of Alpha Particles 559 



R. E. Zirkle, Fellow in Medical Physics, Johnson Foundation, 

 University of Pennsylvania, Philadelphia 



XVII. Motor Responses to Light in the Invertebrate Animals . . 573 

 S. 0. Mast, Professor of Zoology in charge of General Physiology, 

 The .lohns Hopkins University, Baltimore 



XVIII. The Action of Radiations on Living Protoplasm 625 



L. V. Heilhrunn, Associate Professor of Zoology, University of 



Pennsylvania, Philadelphia 



Daniel Mazia, Department of Zoology, University of Pennsylvania, 



Philadelphia 



XIX. Photoperiodism 677 



W. W. Garner, Principal Physiologist in charge of Tobacco and 

 Plant Nutrition, Bureau of Plant Industry, U.S. Department of 

 Agriculture, Washington, D.C. 



XX. Plant Growth in Continuous Illumination 715 



John M. Arthur, Biochemist, Boyce Thompson Institute for Plant 

 Research, Inc., Yonkers, N.Y. 



XXI. The Effects OF Light Intensity UPON Seed Plants 727 



Hardy L. Shirley, Associate Silviculturist, Lake States Forest 

 Experiment Station, University Farm, St. Paul, Minnesota 



