CHEMICAL CORPS BIOLOGICAL LABORATORIES
MEDICAL BACTERIGLOGY DIVISION

Camp Detrick, Frederick, Maryland 14 July 1953

Dr. Joshua Lederberg
Dept. of Genetics
University of Wisconsin
Madison 6, Wisconsin

Dear Josh:

Since the Hayes MS that I have appears to be a final version I am
sending you my extra copy. I have been impressed all along with the fact
that Hayes' major conclusions do not differ decisively from yours and I
regretted the fact that following Hayes' presentation at CSH a consider-
able number of people seemed to get the idea that Hayes' views were in
conflict with yours. I did not feel that it was up to me to correct this
impression during the actual discussion, since there were others present
who were far closer connected with the actual work than I. But I pointed
out privately to a number of people that, as far as I could judge, there
were no major disagreements between Hayes' views and yours and, actually,
you had stated many of these findings in prior publications. I believe
that the initial impression of possible differences arose because refer-
ences to your and Cavalli's studies were not as prominent in lia. es' oral
presentation as in his MS,

In regard to the footnote of your letter of July 8, I fully agree
that residual growth probably cannot account for the qualitative differ-
ences between F* and F-; we are merely trying to see whether and to
what extent it may contributeto quantitative differences in regard to
frequency of recombinants, independent of the type of differences that
occurs in crosses with reversed F polarity. we haven't been able to fol-
low up this question as rapidly as I anticipated, partly because we got
too involved in an entirely different story pertaining to selective effects
of DNA,

I am leaving for Europe on August 14. what are your plans? are you
going to the Congresses or are you going to attend the San Francisco
meetings?

With best regards to Esther and you,

Sincerely yours,

Le

WERNER BRAUN
“B/bls