9 July 1953

Dr. Joshua Lederberg
Department of Genetics
Colle ge of Agriculture
University of Wisconsin
Madison, Wisconsin.

Dear Dr, Lederberg:

Thank-you fer your letter. Your interest and help have been a considerable
source of encouragement. I am very serry it has not been possible for me to
work in your Laboratory.

Thus far we have sent youno cultures, The ones you received must ha¥e
been sent by someone else,

Enclesed is a copy of the revised manuscript that was sent to the Journal
of 5. cteriology one week age, AS you will readily see we have made
marked changes in the manner of presentation, but practically no change
inthe basic information, You may wender why so little has been done

since the last draft was submitted, First of all we have devoted

a great deal of time to the experiments we did with Cohen on phage

which he presented at the Cold Spring Norbor Symposium, Alse we have just
finished 2 manuscript on the new nucleotide and a new polynucleotide

from phage. In addition it has been possible to make great strides in the
preparation ef volumes in basic science fer medical officers, and we even
launched into an experiment of developing and recording discussions

on various medical problems to send off the boys stuck in the woods,

However, do not feel that we have forgotten the copper bug. We are
convinced from preliminary data that analysis of the proteins and DNA
has a great deal of crucial information to offer. And indeed I shall
continue working on it by hook or crook no malter where Tam, In regard
to the classical genetic approach, on the other hand, I have or will have
neither the training or the time to do anything. ‘ve should like very
much to have you explore as much as youcan. It is necessary for m to
leave here inmediately, but arrangements have been made to send you
plates of the organisms, Your strain must be different. ‘le have never
failed to acheive the result when using the conditions stated.
Vie sent our organisms te Ewing for typing and he said they were bo rough
to type. Thus all I know about it is that it came from Cohen, is a coli
biochemically and is hbt by the T phages,

You may wonder why there is still no "per cell" data in the paper, ‘‘e have
done a good deal of work inthat reagrd and have correlations between

direct and plate counts that are always within 5-10% for the normal
organism, However, accuracy within 5% for the "copper organism could

not be consistently obtained so we left it out instead of giving approximate
data, Idiscussed this matter with D.D. ‘Yoods and Moned before deciding it
was best to do it this way. There is little doubt wider any circumstances
that the "copper" organism" is smaller, and we can talk about some day

when we can say just how much 50,

The approach hinted at in Figure 2 will, we feel, yield a great deal

when time allows for the logical experiments to be carried out involving
the isotopic labeling and isolation of the DNA at various points along the
curve. This will eventually be done using methods described by Dr. Jikdon
and myself in a recent J.B.C paper.

Je of course do not know how the Jour of Bact will respond to this paper,
but thatever they say our course is well set. If youcan verify our
findings and work out the genetic aspects while we pursue the chemistry
of the DNA and the virus aspects, it makes little difference, it seems to
me, what they do or donot think. I have a couple more papers te work
on for the J.B.C. so it would be a long time indeed before + would BRaunch
into another revision of this manuscript.

My address in Baltimore wil be: 808 North Broadway, Baltimore, “aryland.
I shall be upt te my cars in learning the practice of medicine again,

but never too busy or far from research to read with great interest any
coments you can find time to send on, iy cerrespondence with you has been
a source of preat pleasure end profit and I hope it continues.

Sincerely yours,

feckineer k-

 

Co

~