.3()() IIAIMATIOX MIOLOflY 



pliismic dotormiiiants of heredity) and in altering the neoplastic properties 

 of tumors. 



It may he of interest to mention that another self-reproducinj^ mutahle 

 cytoplasmic factor, the virus-like "genoide" for carbon dioxide sensitivity 

 in Drusophila (L'lleritier, 1949), which can he transmitted from fly to fly 

 by cell-free extracts, is inactivated in the extracts by X rays. The inacti- 

 vation dose is around 10'' r, similar to that for medium-sized viruses 

 (L'Heritier and Plus, 1950). 



REFERENCES 



Alper, T. (1!)48) Hydrogen peroxide and the indirect effect of ionizing radiations. 



Nature, 162: 615-616. 

 Anderson, T. F. (1944) Virus reactions insid(> of Ijucterial host cells. J. Bacteriol., 



47: 113. 

 (1945) On a bacteriolytic substance associated with a purified bacterial virus. 



J. Cellular Comp. Physiol., 25: 1-13. 

 (1948) The growth of T2 virus on ultraviolet-killed host cells. J. Bacteriol., 



56: 403-410. 

 Hawden, F. C. (1950) Plant viruses and virus diseases. 3d ed., Chronica Hotan., 



Waltham, Mass. 

 Henzer, S. (1952) Resistance to ultraviolet liKht as an index to the reproduction of 



l)acteriophage. J. Bacteriol., 63: 59-72. 

 Benzer, S., M. Delbriick, R. Dulbecco, W. Hudson, G. S. Stent, J. D. Watson, 



W. Weidel, J. J. Weigle, and E. L. Wollman (1950) A .syllabus on procedures, 



facts, and interpretations in phage. In, Viruses 1950, ed. M. Delbriick. Calif. 



Inst. Technology Bookstore, Pasadena. Pp. 100-147. 

 Bonet-Maury, P. (1947) The irradiation of viruses. Brit. J. Radiol., Suppl. 1, 



21-29. 

 (1948) Irradiation et methodes statistiques de titrage des ultra-virus. In, 



Les ultraviruses des maladies animales, ed. C. Levaditi, P. Lepine, and J. Verge. 



Maloine, Paris. Pp. 165-215. 

 Bryan, W. R., and J. W. Beard (1939) Estimation of purified papilloma virus pro- 

 tein by infectivity measurements. J. Infectious Diseases, 65: 306-321. 

 Cohen, S. S. (1949) Growth requirements of bacterial viruses. Bacteriol. Revs., 



13: 1-24. 

 Delbriick, M. (1942) Bacterial viruses (bacteriophages). Advances in Enzymol., 



2: 1-32. 

 (1950) Viruses 1950, ed. M. Delbriick. Calif. Inst. Technology Bookstore, 



Pasadena. Pp. 32-34. 

 Delbriick, M., and W. T. Bailey, Jr. (1946) Induced mutations in bacterial viruses. 



Cold Spring Harbor Symposia Quant. Biol., 11: 33-37. 

 Didbecco, R. (1950) Experiments on photoreactivation of bacteriophages inactivated 



with ultraviolet radiation. J. Bacteriol., 59: 329-347. 

 Dulbecco, R. (1952) A critical test of the recombination theory of multiplicity 



reactivation. J. Bacteriol., 63: 199-207. 

 Fluke, D. J., and E. C. Pollard (1949) Ultraviolet action spectrum of Tl bacterio- 

 phage. Science, 110: 274-275. 

 Friedewald, W. F., and R. S. Anderson (1940) Factors influencing the inactivation 



of rabbit papilloma virus by X-rays. Proc. Soc. Exptl. Biol. Med., 45: 713- 



715. 



