l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 98 



from sublethal exposures of the short wave lengths of the ultraviolet 

 2352, 2483, 2652, and 2967 A. The optimum stimulation point occurs 

 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 are in better condition than those in the controls. The algal 

 cells from the stimulated cultures are slightly shorter and wider than 

 those in the controls. 



LITERATURE CITED 



Brackett, F. S., and McAlister, E. D. 



1932. A spectrophotometric development for biological and photochemical 

 investigations. Smithsonian Misc. Coll., vol. 87, No. 12, pp. 1-7. 

 Chavarria, Antonio Pena, and Clark, Janet H. 



1924. The reaction of pathogenic fungi to ultra-violet light and the role 

 played by pigment in this reaction. Amer. Journ. Hygiene, vol. 5, 

 pp. 639-649. 

 de Fazi, Romolo, and de Fazi, Remo. 



191 5. Azione dei raggi ultravioletti sulla fermentazione alcoolica. Ann. 

 Chim. Appl., vol. 4, pp. 301-329. 

 Fardon, John C, Norris, Robert J., Loofbourow, John R., and Ruddy, Sister 

 M. Veronita. 



1937. Stimulating materials obtained from injured and killed cells. Nature, 



vol. 139, p. 589. 



GlLLES, EdMOND. 



1938. Effets des rayons ultra-violets sur les vegetaux superieurs. 286 pp. 



Lyon. 



HOLLAENDER, ALEXANDER, AND ClAUS, WALTER D. 



1936. Bactericidal effect of ultraviolet on Escherichia coli in liquid suspen- 



sions. Journ. Gen. Physiol., vol. 19, pp. 753-765. 



1937. An experimental study of the problem of mitogenetic radiation. Nat. 



Res. Counc. Bull. 100, pp. 1-96. 



HOLLAENDER, ALEXANDER, AND CURTIS, JOHN T. 



1935. Effect of sublethal doses of monochromatic ultraviolet radiation on 

 bacteria in liquid suspensions. Proc. Soc. Exper. Biol., vol. 33, 

 No. 1, pp. 61-62. 



HOLLAENDER, ALEXANDER, AND DUGGAR, B. M. 



1937. Some effects of ultraviolet radiation on bacteria. Journ. Bact., vol. 33, 

 No. 1, p. 16. 

 Hutchinson, A. H., and Ashton, M. R. 



1930. The effect of radiant energy on growth and sporulation in Colleto- 

 trichum phoinoidcs. Can. Journ. Res., vol. 3, No. 3, pp. 187-199. 

 Johnston, Earl. S., and Weintraub, Robert L. 



1939- The determination of small amounts of chlorophyll — Apparatus and 

 method. Smithsonian Misc. Coll., vol. 98, No. 19, pp. 1-5. 

 Lindner, P. 



1922. Zur Wirkung ultravioletter Strahlen auf die alkoholische Gariing 

 und auf Hefe. Wochenschr. Brauerei, vol. 39, No. 29, pp. 166-167. 



