ULTRAVIOLET RADIATION— MEIER 381 



ultraviolet light and fed to birds whose preen glands had been re- 

 moved and that were living on a vitamin-D-free diet. None of the 

 birds — neither the controls nor those treated — developed rickets on 

 a diet which produced rickets in young cliicks, thus showing the 

 markedly different threshold of reaction to vitamin D deficiency in 

 the different species of birds studied. 



Austin H. Clark and Grace A. Sandhouse (1936), observing the 

 attraction to light of wasps kept in captivity since emergence from 

 their nest, made a brief study of their behavior in ultraviolet light. 

 They found that violet and ultraviolet light consistently stimulated 

 the wasps to greater activity than did monochromatic yellow or green 

 light. In white light with a daylight filter to approximate sunlight 

 quality the wasps made an equal response at about one-hundredth of 

 the intensity of colored light. 



The beneficial action of ultraviolet light, as evidenced by the im- 

 portance of the serious effects resulting when plants and animals are 

 excluded from sunshine and artificial light, still holds open a great 

 field of research. With the high perfection of apparatus, methods, 

 and technique now in progress, new research on this subject is eagerly 

 anticipated. 



The word radiation appears most often at this time in the work 

 of scientists. Under this name are included all the forms in which 

 energy can be extended into space without material support. Ultra- 

 violet, infrared, visible light, X-rays, radio waves, and many other 

 forms are included in this term radiation. Although nothing seems 

 more simple than a light ray, actually much remains to be learned 

 about it. 



BIBLIOGRAPHY 

 Abmand-Delille, p. 



1935. Light and heliotherapy in nutrition. Journ. State Med. London, vol. 



43, no. 12, pp. 709-719. 

 Clark, Austin H., and Sandhouse, Grace A. 



1936. The nest of Odynerus tetnpiferus tnacio Bequaert, with notes on 



the habits of the wasps. Proc. U. S. Nat. Mus., vol. 84, no. 3005, 

 pp. 89-95. 

 CoBLENTz, W. W., and Staib, R. 



1934. Data on the spectral erythemic reaction of the untanned human skin 



to ultra-violet radiation. Bureau of Standards Journ. Research, 

 vol. 12, no. 1, pp. 13-14. 

 Crew, W. H. and Whittle, C. H. 



1936. Sunburn and windburn. Science, vol. 84, no. 2179, pp. 30^310. 

 DuGGAR, Benjamin M. 



1936. Biological effects of radiation, vols. 1 and 2, 1342 pp. New York. 

 Friedmann, Herbert. 



1935. Notes on differential threshold of reaction to vitamin D deficiency in 



the house sparrow and the chick. Biol. Bull., vol. 69, no. 1, pp. 

 71-74. 



