232 



THE EFFECT OF IONIZING RADIATIONS 



radiations of young cells and of cells in division is not due to the effect 

 of ionizing radiations on nucleic acids. It may be predicted furthermore 

 that the part played by direct collision is of less significance than that 

 produced by the products of water radiation. 



1.5 



1. Control 



2. 50,000 r 



0.20 



0.25 



0.30 



X lO'^A 

 Fig. 13. Effect of x-ray irradiation on the absorption spectrum of sodium desoxy- 

 ribonucleate (40 micrograms per 1 cc). Abscissa: Wavelength in angstrom units; 

 ordinate: optical density E. 



Ionizing Radiations and Proteins 



The effect of ionizing radiations on proteins has been the subject of a 

 large number of investigations. Protein denaturation and precipitation, 

 viscosity decrease, and changes in the absorption spectrum and in the 

 sedimentation constants have been observed when proteins were irradi- 



