25 September 1958
Dear Paul,
We have Arthur Aronson from Spiegelman's lab. with us this year,  and I would like to take the opportunity to turn over to bacteria as a source of soluble RNA.  Have you by any chance anything written up about the way you prepare it?  If you have we would be most grateful for a copy; even if you have nothing in detail a very rough outline would be of some help.
I am trying to fractionate the soluble RNA to obtain a fraction which will take up one amino acid only, but so far without success.  Have you made any progress in trying to pick up small labeled fragments?
Zillig, of Munich, reported at Vienna that he was getting nice bands with high voltage paper electrophoresis, but he was right in the middle of it and wasn't sure whether each band was "pure".
I shall be at Harvard for the Spring term, and may come out west next summer, so perhaps we can arrange to meet on one side or the other.
With best wishes,
Yours ever,
Francis
F.H.C. Crick