December 4 , 1956

Dear Abe?

I noticed your abstract in GENETICS on effects of versene/ on
sexual fertility in E, coli. We would like to use your finding. if
you are agreeable to letting us have a mora detailed protocal, as a pos~
sible improvement in our own technique. We don't want to "butt in” on
your own possible further analysis, and hope you wlll be following this
up-—~co let us hear from you.

Inter alii, we've been trying to confirm Hirota's claim that Co”
induces F~ mitants from F* (Nature, duly 14) but so far it isn't going
so well. Dave Skaar, Alan Richter and I just finished an anlysis on the
effect of motility selection: this appears to be a competitive advantage
on the part of spontaneous F- mtants over the F+ background,

Yours sincerely,

Joshua Lederberg
Professor of Genetics