REPORT OF THE SECRETAKY 117 



for each of these wave lengths at approximately two-thirds of the 

 lethal exposure. The stimulative action is not transitory but has 

 persisted in the cultures over a period of 2 years. At the end of 

 2 years' time, the cells in the stimulated cultures were in better 

 condition than those in the controls. The algal cells from the stimu- 

 lated cultures are slightly shorter and wider than those in the con- 

 trols. The description of this research will be published under the 

 title "Stimulative Effect of Short Wave Lengths of the Ultraviolet 

 on the Alga Stichococcus hacUlaris Naegeli." 



A series of experiments was carried out by Dr. Meier in which 

 both spores and amoebae of the slime mold Polysphondylium vio- 

 lacea were irradiated separately with wave length 2652 A (lethal to 

 green algae in 60-second exposure). Since normal plants resulted 

 from all the different exposures varying from 30 seconds to 1 hour 

 at an intensity of 2,000 ergs/cm.^/sec, experimentation with this slime 

 mold was discontinued. It seems possible that the ultraviolet radia- 

 tion does not penetrate either the amoebae or the spores. 



EQUIPMENT AND MATERIALS 



Several important pieces of apparatus have been developed in our 

 laboratory and shop. The facilities available for constructing spe- 

 cially devised apparatus during the progress of an experiment is so 

 essential to this type of research that its importance and the services 

 of Mr. Clark and Mr. Fillmen cannot be overemphasized. A much 

 needed modern autoclave has been added to the physical equipment. 

 Dr. Meier's collection of pure cultures of algae has been added to 

 by 14 cultures of green algae from Dr. E. Kol, Szeged, Hungary, 

 and 7 cultures of blue-green algae from Dr. Lee Walp, Marietta, 

 Ohio. 



PERSONNEL 



No changes have occurred in the status of the Division's personnel. 

 The capable services of E. R. Brydon and O. E.. Zipf have been con- 

 tinued by the Works Progress Administration during the year. 



PAPERS PRESENTED AT MEETINGS 



New facts in photosynthesis. Presented by E. D. McAlister before the Botani- 

 cal Society of Washington, D. C, November 1, 1938. 



New evidence of the formation of a carbon dioxide-combining intermediate 

 during photosynthesis. Presented by E. D. McAlister before the American 

 Society of Plant Physiologists, Richmond, Va., December 28-30, 1938. 



An apparatus and method for the determination of small amounts of chloro- 

 phyll. Presented by Earl S. Johnston and Robert L. Weintraub before the 

 Division of Biological Chemistry of the American Chemical Society, Baltimore, 

 Md., April 3-7, 1939. 



Carbon dioxide assimilation by green plants. Presented by E. D. McAlister 

 before the American Chemical Society at the University of Delaware, Newark, 

 Del., May 17, 1939. 



