94 ANNUAL REPORT SMITHSONIAN INSTTTUTION, 1940 



Cultures of stimulated algae when exposed to lethal intensities of 

 the full ultraviolet spectrum proved to be less sensitive to the kthal 

 amounts than were the control cells. Even those cultures that had 

 been stimulated by four successive exposures and which contained 

 numerous disinte^jrated cells were less sensitive to the lethal amounts 

 than were the control cells. 



A detailed account of this research will be published under the 

 title "Increased Stimulation of the Alga Stichococcti^ bacillaris by 

 Successive Exposures to Short Wave Lengths of the Ultraviolet." 



PERSONNEL 



Dr. Jack E. Myers was granted a National Research Fellowship 

 to carry on his research in photosynthesis in the Division's labora- 

 tory. This fellowship, which began September 19, 1939, has been 

 renewed for a second year. 



L. A. Fillmen, by an executive order, was appointed to the civil 

 service on May 20, 1940, and transferred to the staff of the Astro- 

 physical Observatory as instrument maker. 



PAPERS PRESENl-ED AT MEETINGS 



Cultivation of excised oat leaves. Presented by Robert L. Weintranb before 

 the Americaa Society of Plant Physiologists, Colnmbns, Ohio, December 28, 1939. 



Induction and related phenomena. Presented by B. D. McAlister at the 

 symposium on photosynthesis, Section O (Chemistry) of the American Associa- 

 tion for the Advancement of Science, Columbus, Ohio, December 28, 1939. 



Plant tissue cultures. Presented by Robert L. Weintraub before the Botani- 

 cal Society of Washington, D. C, March 5, 1940. 



Sensitivity of pinnts with special reference to light. Presented by Earl 

 S. Johnston before the Gamma Alpha Scientific Fraternity, The Johns Hop- 

 kins University, Baltimore, Md., April 5, 1940. 



Time course of photosynthesis and fluorescence. Presented by E. D. Mc- 

 Alister before the Physiological Colloquium, Washington, D. C, June 10, 1&40. 



PUBLICATIONS 



Johnston, Earl S., and Weintkattb, Robert Ti. The determination of small 



amounts of chlorophyll — apparatus and method. Smithsonian Misc. Coll., 



vol. 98, No. 19, pp. 1-5, 1939. 

 MinER. Florence E. Stimulative effect of short wave lengths of the ultraviolet 



on the alga Stichococcus Ixwillaris. Smithsonian Misc. Coll., vol 98, No. 23, 



pp. 1-19, 1939. 

 Johnston, Easl S. Sunlight and plant life. Scientific Monthly, vol. 50, June, 



pp. 513-525, 1940. 



Respectfully submitted. 



Earl S. Johnston, Aasistant Director. 

 Dr. C. G. Abbot, 



Secretary, Smithsonian Institution, 



