UNITED STATES
ATOMIC ENERGY COMMISSION
WASHINGTON 25, D. GC.

March 29, 1950

Dr- Joshua Lederberg
Genetics Department
University of Wisconsin
Madison, Wisconsin

Dear Josh:

This is primarily a note of apology for the relativg@ylong silence from
Washington. The reason for the silence is that between travel and things
picking up around the office a bit, I have very little time to spend
thinking about our problems. In point of fact, I had time to only
casually glance at your proposed manuscript. I think things should set-
tle down in a couple more weeks so I can again accomplish something.

Relative to your letter describing your results on a radiation H-226,
as you remember in our talks at New York, I mentioned that a grad
student was playing with this problem in Ithica. In general, his re-
sults agree with yours, but you are much further along with the work.
It is very interesting and not quite what I would have expected in
view of some other work which has been done recently on an irradiating
haploid and diploid organism& Unfortunately, I don't have your letter
here so JI cannot go into any detail.

i_have attempted Pes incle celling session recently with some rather

we results. The first time cells just failed to grow and the
second time they grew too damn fast since I had made up a new batch
of medium and the micro colonies grew together while I was trying to
catch a little sleep. I shall attempt to get on the ball again as
goon as possiblee

I was in Ith§ca three days, a couple of days ago, and talkei with Sher-
man a bit. He would be willing to publish a little description of

the single celling technique separately. Do you think it worthwhile to
describe the technique in some detail, pointing out its general useful-
ness in attacKing problems of this type with a possible extension to-
ward €ytolog# to be submitted along with this manuscript and appear-
ing probably /next to it? I could bat that out in half an hour or so
and it might help people interpret the pebigress we do include.

I have been trying to figure out a logical excuse to visit Madison,
without much success so far. The best idea, so far, would be to come
Dr. Joshua Lederberg -2- March 29, 1950

to Madison on a trip which I must make soon to the Argomne National
Laboratory in Chicago. I probably would hit Purdue on the same
trip. I shall let you know when this becomes more definite.

Sorry to be so unproductive the last two or three weeks, but it is
a busy life these days.

Very truly yours,

é
/;
M. Re Zelle

Genetics Branch
Division of Biolegy and Medicine