224 



A. M. KUZIN 



5. 



E 



o 



CM 

 CO 



O 



U 



'4-> 



o 



NACI 

 00-0-5M 



phosphate 

 0-01 M 



NACI 

 0-5- 



20M 

 pH7-0 



NACI 

 •OM +NH. 



0-0-OIM 



0-1- 

 l-OM 



NaOH 

 0-5 M 



Chromatographic Representation of the Fractionation of Rat Thymus DNA 

 (in per cent from S difference in the wave-length 260 and 320 ni/x) 



Chroma to - 



grains! OJ 



retm-n (%) 



from the 



initial 



t Average data from two chromatogranis. 



% The fraction which is eluted by (J-Ol m phosphate buffer pH.70 during]washing the columns after DNA 

 was put on. 



Fig. I .—Polymerization spectrum of DNA isolated from rat thymus. 



A, DNA from unirradiated rat. 



B, irrad. 1,000 r in vivo (10 min after irradiation). 



C, irrad. 1,000 r in vivo (24 hr after irradiation). 



