August 25, 1951.

Dave and Miriam Bonner,

Yale University,

Osborn Botanical Laboratory,
New Haven, Connecticut.

Dear Miriam and Dave:

Firet, thanks for sending me the cultures I asked for. They all
look verfectly all right: I don't think sitting in Mirdan's lap could
do any harme

From your posteard, I gather you may be leaving for Oak Ridge fairly
soon. Esther and I do hope you can manage to enjoy it dowm there: it gave
me the creeps the ones 2 visited.

We are finally getting down to bueiness on a long-noglected task:
preserving our cultue collection. Fortunately, almost everything important
was still recoverable from agaryials, although some were over two years
old. We're using the Hershey-Browm method of drying the cultures, (with Call
in the vials; no freezing, except dome by evaporation), with apparent
satisfactory results. There are Yket a fow items I wanted to check with
you. Are you leaving OBL soon? Are you taking the lyophil collection with
you, or are you leaving it in anyone's custody at OBL. I'r interested, of
course, mostly in the oolifest.

2

Do you recall our discussion of W-45 (Lac,-)7 Al} of my recent cultures

of thie strain now show a slow fermentation of lactose, bit poor growth on
EMB. A W-45/1 mutant waa juet pulled out, however, which accords better with
my recollection of what #45 had used to behave like. D& you have any ¥-45
cultures, old and reo:nt, that could be used to check on this, and to help
clear up the discrepancy in our findings re the leakiness of this mutant.

The only W- mutants of any significance that seem to have been lo«+ ‘are
W327 and W-328, both Malf Glu- derivatives from ¥-108 we could pros sy
get them again, but if you happen to have the lyophil tubes on these, { would
appreciate having them. We are also missing ¥-239 (Glu-), but this one's not
at all inportant.

Ow collection of Y~ cultures is quite incomplete, but we anticipate no
pressing needs in that direction. However, can you give me the history of
Y-161 and of Y-256: we have, I thihk, the cultures but no other data on them.

Please let us know if we cah reciprocate these favors in any Way
Be: + wishes,

Joshua Lederberg

=.