Ochober 7, 1955

Miss Phyllis Fried
Dept. Zoology
Columbia University
New York 27, N.Y.

Dear Phyllis:

I would appreciate the favorf#if you could send me copies of h# lact and
h-lac- as were used in the receft work on mutation in stationary populations.
Do you happen to know if the latter 1s the same mitant that I sent Francis
in June 1949? Anyhow, we did not keep copies at that time, and I am interested
(at some possible future time) in trying out a technique for testing for lysis
and turnover in such populations, and I might as well use a precedent situation.

Can you also give me Frahcis' exact address? I asspme they are well estab-
lished at Tokyo by now; we had from them last at Portofino. While you're giving
directory service, I wonder if you can also confirm Fvelyn #itkin's whereabouts.

Thanks very auch,

Yours sincerely,

sf Lederberg

/