VIRUS GENETICS, MULTIPLICATION, AND PHYSICS 201 



case of a nucleic-acid precursor. It is this intimate specific charac- 

 ter which is expressed in the antigenic nature of the bacterial 

 contents. 



In the bacterium, use is made of the nucleoprotein precursors 

 either as enzymes for causing the synthetic metabolism to pro- 

 ceed rapidly and effectively, or as units which form part of the 

 new genetic material necessary to carry the basic cellular char- 

 acter over into the next division. 



None of this process is clearly understood at the present time. 

 It seems speculatively reasonable, however, that rather rapid 

 chemical rearrangements can be made, utilizing energy by direct 

 transfer to form either nucleic-acid units of molecular weight 

 2,000 or so, or small proteins of the same size. Let us guess that 

 the nucleic acid is first made: the egg before the hen. (The order 

 is not important, protein could be made first.) This nucleic acid 

 is then specifically attached to protein molecules already in the 

 cell and, as the spacing of the nucleosides is rather flexible (Wil- 

 kins, private communication), this local attachment causes the 

 opposite side of the nucleoside to form the same protein pattern, 

 but in terms of bases or sugars. 



The small proteins now being formed then find themselves 

 able to attach to the bases or sugars if their over-all pattern 

 fits the proper structure, which is that of the protein of the 

 parent cell. Any other di- or tripeptides do not attach and prob- 

 ably suffer a new enzymatic digestion until they are reassembled 

 in the correct way. Thus the nucleic acid serves to transfer the 

 parental pattern to the new molecular generation. 



Thus there rapidly develops a population of new protein and, 

 in turn, this prints its design on new nucleic acid until the cell 

 carries a high proportion of subunits ready for assembly. 



The assembly process in the host follows the orderly develop- 

 ment of the cell. In a virus-infected cell it conforms to the as- 

 sembly needs of the virus. 



All the above is speculative. It may be words and no more. It 

 is the kind of basic thinking which will one day lead some- 

 one to the truth and we therefore include it with no great 

 apology. 



