KW: thanks for reprint, trp cultures; morph mutants from mustard; methylcholanthrene; many cys, met mutants; zero from sponatenous controls; "The CSH symposium was very fine. good discussions .. Spiegelman, Sonneborn, Hershey,; Dave [Bonner]; van Wagtendonk; "your home in PA went to Art [perhaps Giese?]; !! no mention of E coli recombination; jl 9/11/99 ..