March 27, 1952

Dr. Rollin Rotchkias
Rockefeller Institute for Medical Reseanh
New Work 21, N.Y.

Dear Rollin:

T haven't given very much thought to either the Boston or Baltinore
meetings, as I don't expect to be attending either. I talked with Ed Tatum
a coupld of weeks ago about the former. As you say, the program looke very
crowded. Zinder will be giving e short paper there in the gencral session
anyhow; if thore is time and the occasion really demands it, perhaps he
could add to the discussion from the floor. But this should not 4nfluence
your plans. As to Baltimore, probably neither of us will be there after all.
I don't ses how we can really "discuss" your paper undor the cfhreurnstances.
If you thought it desirable, why don't you yourself cuote our experiments
(and if you can find it, our point of view) at the meeting? Ye could have
a private discussion by mail. If thie seems to have dialectic possibilitios,
we could arrange o dlalomue for the publication (as Mac seems to want). Whether
or not we do this, I would Yope there would be an cocasion to discues: 1)
that the "transformations" ara genetic transductions (per Webster's dic$ionary)
and not induced mutations as often understood, and 2) the extent to which
a Figorous view of the experinonte leaves room for an organized alemont in
TP, on the one hand, or a protected active component (DNA?) 4n PA on the other.
The gonotic complexity of IlT-capsular TP, and the newly revealed scope of
beth TP and FA are, I think, pertinent. Or are we to think of crossing-over
in "moleaules"? I think you are quite right that we are looking mostly at
the vehicle in FA (and perhaps TP also?), and DNA or DNA-protein would be
es good a bet as any for the active component, Mere may be o bit of a techni-
sal problem in the adsorption and penetration of the stripped FA, even if the
atripping is possible. Should we try serum? No cofactors are needed for FA now.

If you do ofte Salmonella trandduoction, may I ask that you eaphasize that

Ge cold sex is altogether another story. Ao often as I do this, it sti!1 comes
back gartled.

Zinder should win his PheD. this epring, and has no comtsents here. I would
hope that he will continue Salmonella studies wherever he goos. On the other
hand, I've beon deeply interested in Salmonella for some six years, and expect
to continuc our program, probably along "biological" lines. I appreciate your
courtesy in conoulting me about your plans, but see no occasion for any conflict
that we can't avert by open discussion. Zinder will have to make up his own
mind if he 4a formally approached by both Schneider and yourself. I think that
it's really too bad if a de facto arrangenent couldn'¢é be worked out that would
tet him share tho two contacts. Alternatively, would there bo any point or pos-
sibility of a scheme to spend one yenr with you, and then go over to Sch? I
haven't discussed any of thie with Zinder, but at this dletance 44 somds
worthwhile. He would lie to learn soze blo-physice and -chemtetry before
deciding or settling his plansy but I think the advantazes might be reciprocal.

Youre sineorely,

Joshue Lederberg