VIRUS GENETICS, MULTIPLICATION, AND PHYSICS 



191 



TABLE 8.1 



Number of mutants. Number, y, observed 

 x\ in a group or with x or more yx 



clone (r mutant) {r) 



Number observed 

 with X or more yx 

 (iv mutant) (?/') 



instead of being uniform as required for the mutating template 

 method. So that again this is experimentally disallowed. On the 

 other hand, the requirement imposed by the exponential growth 

 method, that the number of clones with x or more mutants vary 

 as 1/x, is quite reasonably well fulfilled. Perhaps more work 

 needs to be done before strong assertions are made but, within 

 the compass of the data of this very well conceived experiment, 

 the growth method of Fig. 8.1b or 8.1c is definitely indicated. 

 Since the next generation is produced by the splitting of one 

 individual into two individuals, there is really no way in which 

 "genetic" P^^ can be fixed in one generation and held there, be- 

 cause the P^- will be divided and will then take part in all the 

 characteristics of the new phage generation, not all of which need 

 be "genetic." So the experiment of Kozloff and Putnam, Maaloe 

 and Watson, and Forro is in keeping with Luria's findings. 



Summary of Pertinent Facts About Viruses 



In order to guide the formulation of hypotheses about virus 

 multiplication, we give here a summary of facts about viruses 

 which seem significant. Many of these facts are derived for bac- 

 terial viruses, but evidence is growing that animal viruses con- 

 form to the same pattern. Plant virus may also do so, but entry 

 into the infected cell is probably by different means. The signifi- 

 cant points are: 



