September 28, 1946,

Dear Dr. Edwards:

Since our last correspondence, a copy of Kauffmann's book has
come into my possession, and I discovered in it & discussion of in- |
vestigations on Salmonella nutrition such as I hed not previously
suspected, This is particularly interesting because the group of
Strains that I have been wo: king on so far has been highly discourg¢d
aging - with the exception of a para A and a cholerae suis strain
that I have already mentioned, and pullorum and gellinarum, most or
all seem to grow quite well on a glucose asparagine medium, or with
the addition of thioglycollate. However, this litercture suggests
that there are a mumber of organisms which would turn out to have
useful nutritional reuirements- those which will not -grow on bimmons!
glucose agar. For example,ll IV variants of typhi-wuriun which you
reported on in 1939. According to Mauffmann!s review otuer strains
which may Betisfy this criterion are abortus¢ ovis,typhi suis, and
sendai.(I notice this last named as a subject again of one of your
investisevions where this test was one of the differentials separa-
ting sendiy from miami.

“Ou should he doing this investigation abercat eervice if you
were to send me a collection (as extensive as you can conveniently
manage)of strains which fail to grow on minimal media such as Sim-
mons' agar. in the meantime, I am working on developing nutritional
mutants of typhi-murium. That is quite a time-consuming afrair ,koxvexe

“lth the most sincere apprecieti&ons, bincerely yours,

Joshua Lederberg