January 23, 1951.

Dr. He Demerec, Director,
Long Island Biological Laboratory,
Cold Spring Harbor. Leles NwYe

Dear Dr. Demerec:

Thank you for the invitation to participate in the forthcoming
Symposium on Quantitative Biology on "Genes and Mutations". It is
with great pleasure that I accept this invitation, Subject to revision
after closer study, tha title of mx paper will probably be “Recombi-~
nation analysis of bacterial heredity", and it will encompass tha
divers lines of work based upon crossing experiments which have been
developed since this phenomenon was first announced at the Symposium
five years previously.

The content of ay proposed paper will relate so clostiy to the dif-
ferent lines of work being pursued here that I feel it quite essential
to propose a joint authorsnip, at least for the publication, and pre-
ferably for the announcements as well.

As to accomodations, I hope that a reservation for ‘irs. Lederberg
and myaelf will be possible for the duration of the Symposium. Your travel
funds should be reservsd primarily, of course, for the benefit of trans-
Atlantic visitors, and I should not like to make any request which would
embarrass these projects. However, a journsy of a thousand niles (by auto)
4s not inconsiderable, and if a partial reimbursement of expanses were
possible, it would be appreciated. May I ask now asrely to ba kept in
mind for a place near the ond of your priority list.

Your letter leaves room for suggestiogs on the program. It is perhaps
too late for amendments, but there may still be time for some consideration
of these comuents,

Except that microorganisms are given a somewhat anomalous emphasis, I
am very much pleased with the program in general. Having had the considerable
pleasure of a visit with Ephrussi last autuan, I might have preferred to
meet one of his colleagues - L'Heritier, for example, = if it were still
possible. But this appears to be a readily amgeptable exception to the rule
that most of the visitors have not been recently accessible. The only other
comment on the general program is the possible desirability of adding
Dr. (&i¥re.) M. M. Green to section III (perhaps as a discussant).
I am rather divided on what to do with microorganisms. Hy first
reaction is thag they are given undue emphasis in a symposium of the
given title, but this is followed by a listing of twomor three other
workers who should also be included. To put this first, I think that
H. B. Newcombe and B. D. Davis would be welcome additions (at least
as discussants) for the pzoblem of phenotypic delay.

Bacterial cytology, in the English school, is unfortunately not in
a very informative status for genetic interpretations. If there were
any single worker who probably has made the most germane and critical
contributions, I would nominate Klieneberger-Nobel, and I hope that
Ait might still be possible to cansider her as an alternative or supplement
to Bisset. The latter’ss speculative remarks on subjects of genetic in-
terest rest more on the unconfirmed statements made 20 years ago by
other workers than upon his own observations, which are mach more of
morphological than cytogenetic interest. Klieneberger—Nobel has had a
broad experience, cautiously interpreted, much of which is directly
relevant to problems of nuclear and sexual cycles in bacteria. I would
urge, in the strongest terms, that consideration be given to inviting
her participation in the discussions of bacterial cytology.

On the other hand, it 1s possible that the emphasis given to micro-
organisms in this conference may prejudice the possibility of a broader
discussion of their genetics, as such, at alater date. But I cannot
suggest what practical measures could still be taken in this direction.

I hope that Atwood will be encouraged to emphasize his very intriguing

work on radiation effects in Neurospora heterokaryons, which he might be
discouraged from doing by the subtitle ("bacteria and bacterial viruses").

Sincerely yours,
Joshua Lederberg.

P.S. Re l'Heritier, local information has it that he is politically

safe", and not likely to encounter difficulties with passport.