82 



ERNEST POLLARD 



L-Arglnine- C incorporation 

 by E. coli after deuteron 

 bombardment 



3 6 9 12 IS 



l6-5x|0'°d/cm2 



3 6 9 12 15 3 6 9 12 15 

 Fig. 3. — IncoqDoration of L-arglnine as affected by various deuteron bombardments. 



u 



400 800 



Radiation energy loss 



1.200 



1.600 electron ^ 

 volts per 100 A 



Fig. 4. — A plot of the sensitive cross-section for seven metabolites against the rate of 

 energy loss. The initial slojae is found from •'"Co inactivation. Three groupings appear: 

 arginine, histidine, leucine, ^soleucine and proline are all characterized by higli sensi- 

 tivity at high rates of energy loss; methionine and uracil have rather low sensitivities 

 for such radiation, and glucose is consistentlj^ low. Probably naetabolites of the first 

 grouping involve long thin objects, but the others are more nearly spherical. 



