IONIZING RADIATION AND VIRUSES 



79 



teristic relation for random bombardment which is expected to 

 produce the result (see, for example, Pollard, 1953) 



In- = -SD 



no 



(3.5) 



100 



40 60 



Deuterons/ 



Fig. 3.4. Percent survival of T-1 phage after various amounts of deuteron 

 bombardment. Tlie relation In (»/«o) = —SD is seen to be obeyed (Pollard 

 and Forro, 1951). 



where Hq is the initial measure of infectivity, 7i is the amount 

 left after a "dose" D of deuterons per unit area, and S is the 

 effective cross section. S is determined from the above relation, 

 and the problem of interpretation is to take this theoretical 

 number and show its significance in virus structure. It will be 



