PHYSICAL AND BIOLOGICAL FACTORS 947 



of the complexity of cell physiology and the ubiquitous nature of the 

 energy absorption, it is not surprising that the effects of radiation are 

 manifested in many ways and that many factors have the capacity of 

 influencing the radiation responses. 



The events that are immediately associated with the absorption of 

 radiation are fairly independent of temperature over a wide range. How- 

 ever, the subsequent reactions of injury and recovery are subject to tem- 

 perature influence and metabolic activity. The existence of activated- 

 water reactions in vivo as well as in vitro is suggested by the rather 

 parallel influence of hypoxia and protective substances on the behavior of 

 aqueous solutions and living systems to radiation. The mode of action 

 of these modifying factors has not been settled, however. There is 

 reason to think that the chemical effects of ionization and excitation are 

 responsible for the early cytological damage following moderate dosages 

 of radiation and that this, in turn, bears a causal relation to the over-all 

 injury in the mammalian organism. 



REFERENCES 



(Information regarding availability of government reports indicated by an asterisk 

 may be obtained from the Office of Technical Services, Department of Commerce, 



Washington, D.C.) 



Abrams, H. L. (1951) Influence of age, body weight, and sex on susceptibility of 



mice to the lethal effects of X radiation. Proc. Soc. Exptl. Biol. Med., 76: 



729-732. 

 and H. S. Kaplan (1951) The effect of shielding on mortality following irra- 

 diation. Stanford Med. Bull., 9: 165-166.. 

 Aebersold, P. C, and J. H. Lawrence (1942) The physiological effects of neutron 



rays. Ann. Rev. Physiol., 4: 25-48. 

 Ahlstrom, L. H., G. Hevesy, and K. Zerahn (1947) Toxische Wirkungen von 



Thymus-histonen Protaminen. Arkiv Kemi, Mineral. Geol., 23A: 1-10. 

 Allen, A. O. (1948) Radiation chemistry of aqueous solutions. J. Phys. Colloid 



Chem., 52: 479-490. 

 Allen, B. M., O. A. Schjeide, and L. B. Hochwald (1950) Relation of low tempera- 

 tures to X-ray injury of hematopoietic tissue of tadpoles (preliminary account). 



Proc. Soc. Exptl. Biol. Med., 73: 60-62. 

 Allen, J. G. (1951) The beneficial effects of head shielding in 20 dogs exposed to 



450 r total-body X radiation. USAEC Report ANL-4625,* p. 60. 

 Ancel, P., and P. Vintemberger (1927) Influence de la temperature sur la radio- 



sensibilite d'oeufs d'oiseaux et de batraciens. Compt. rend. soc. biol., 97: 



796-799. 

 Anderson, R. S., and H. Turkowitz (1941) The experimental modification of the 



sensitivity of yeast to roentgen rays. Am. J. Roentgenol. Radium Therapy, 



46: 537-542. 

 Baclesse, F., and J. Loiseleur (1947) Modifications de la radiosensibilite cutanee 



du lapin au cours de l'hyperglycemie experimentale. Compt. rend. soc. biol., 



141: 743-745. 

 Bacq, Z. M. (1951) L 'action indirecte du rayonnement X et ultraviolet. Experi- 



entia, 7: 11-19. 



