Dec 14 1945 Dear Lederberg: Thanks for your interesting letter about pab and leucineless. On my very hurried visit with the Ryans, Dr Ryan told me about some of this work. Your findings are most interesting. As regards the leucineless situation there are several other strains in addition to 8839, which Regueny[?] worked on and found to be different from 33757. Regueny[?] has been planning to use these in his PhD thesis problem and I therefore don't feel free to send them without consultation with Regueny[?] and further consideration. He has been in the Navy a couple of years and will soon be back to continue. 33757 has been published and therefore is, according to my way of thinking, public property. I'd say, therefore, anything you do with it is OK and all to the good. I've written Ryan about [END PAGE ONE] [BEGIN PAGE TWO] the leucineless situation and I suggest you discuss it with him. I'll go over the pab work with Miss Zimmer soon and see how she stands on tests for allelism. Again shes [sic] using these as a thesis problem and I don't feel free to send out other mutants without its being fully talked over with her. With best regards, I am Sincerely yours GW Beadle