vi Foreword 



a forward step in advancing one of the most fundamental subjects in 

 science. 



The Society is deeply indebted to all who contributed to the 

 success of the symposium and of this volume. Especial appreciation 

 is due Dr. William Seifriz for the knowledge, skill, and enthusiasm 

 which have made the project possible. 



W. E. LooMis 



Secretary-treasurer 

 Ames Iowa American Society of Plant Physiologists 



June "l, 1941 



