264 BACTERIOPHAGES 



infected bacterium. There is a precursor pool containing about 

 80 phage equivalents of DNA which is fed from the medium and 

 from the host-cell nucleic acids and which is drawn upon by 

 maturing phage particles. The transport of phosphorus from 

 the medium to the precursor DNA pool requires on the average 

 8 to 9 minutes and from the pool into mature phage an additional 

 7 to 8 minutes. The great interest in this pool of phage-precursor 

 DNA arises from the fact that its size and kinetic properties are 

 similar to those deduced from genetic experiments concerning the 

 mating pool of vegetative phage. This striking similarity in 

 properties leads to the conclusion that the pool of phage-precursor 

 DNA is the material of which the mating pool of vegetative 

 phage is composed. 



