APPENDIX 9 



REPORT ON THE DIVISION OF RADIATION AND 

 ORGANISMS 



Sir: I have the honor to submit the following report on the 

 activities of the Division of Radiation and Organisms during the 

 year ended June 30, 1940 : 



As in previous years the Division has been in part supported by 

 a grant from the Research Corporation of New York. 



During the past year the Division has continued its active work 

 on problems of photosynthesis and factors affecting plant growth, 

 both from a nutritional and radiation point of view. Dr. McAlister, 

 with the assistance of Dr. Myers, has continued his induction-period 

 studies of photosynthesis with the very valuable addition of simul- 

 taneous records of fluorescent intensities. Drs. Johnston and Wein- 

 traub have further improved their apparatus and technique in carry- 

 ing out their investigation of respiration, photosynthesis, and chlor- 

 ophyll formation as affected by light. 



Mrs. Chase has extended her work on the stimulative action of 

 ultraviolet on algae. Dr. Weintraub has completed the initial phases 

 of some of his growth studies and opened up others to be investi- 

 gated. Mr. Clark has undertaken the construction of an improved 

 and simplified apparatus of his own designing for the accurate and 

 rapid determination of minute amounts of carbon dioxide. 



As an outgrowth of the induction-period studies, Dr. Myers is 

 further investigating the relation of the induction behavior of 

 Ghlorella to the previous condition of culture. In addition, he is 

 planning a comparative study of various methods for the measure- 

 ment of photosynthesis and of the photosynthetic behavior of vari- 

 ous kinds of plants. Mr. Clark and Mr. Fillmen have given valuable 

 assistance in the designing and construction of apparatus. The divi- 

 sion library has been improved greatly through the kindness of Mr. 

 Corbin, the Institution's librarian. One hundred and fifteen volumes 

 of periodicals have been bound, and other material has been made 

 more accessible. 



PHOTOSYNTHESIS, RESPIKATION, AND CHLOROPHTIX. FORMATION 



A great many simultaneous measurements of the rate of carbon 

 dioxide uptake and the intensity of fluorescence have been made 

 during the induction period of photosynthesis. Tlie rapid spectro- 

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