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CHARLES A. THOMAS, JR. 



30 35 



TUBE NUMBER 



Fig. 4. The results of the autoradiographic experiment. A. The experimental 

 plan. B, E, and F. The frequency distribution of star sizes; the number of stars 

 having r rays plotted against the star size r. C and D. DXA chromatograms of 

 intact molecules and broken molecules, respectively. The sohd line is optical den- 

 sity; the broken hne, P\ The shaded fractions were .^elected for autoradiography. 

 The star population arising from these samples is shown in E and F. (From Ruben- 

 stein et al, 1961.) 



approximately quarter-molecules when stirred at the critical rates of 

 shear. This is just what one would expect for a linear molecule, while a 

 circular structure would be expected to break repeatedly into fragments 

 which would be substantially smaller than one-half. When a hoop- 



