December 3, 1949.

Dr. R. Latarjet,
Institut du Radiua,
26 Rue d'Ulm,

Paria 5, France.

Dear Latarjet:

I would be very pleased if you could send me the Lisbonne—Carriere
strains, although lysogenicity is so common that it would not be dif-
ficult to resiaoclate comparable strains. However, they made some par-
ticular observations on changes of. characteristics that would have to
be repeated on the same strains.

Would it be too much to ask another favor? The publications of L.
and C., ete., are scattered through a number of articles in CR and in
the Ann Inat Past. Is there any chance that reprints of any of these
are still available, or stored away in an attic somewhere?

irs. Lederberg has been stugiging the transmission of lysogenic
virus in crosses, and has run into some very peculiar results, in
particular that crosses of sensitive with lysogenic often give
sensitive diploid progeny. The phage seems to be interrupted or
else specifically segbegated at the sexual cycle.

We would be very interested to learn details of your induced
virus mutations. What characters are involved?

We have not succeeded in accomplisking disinfection of lysogenic
bacteria by any experimentak procedure with consistent reuilgs. A very
small fraction ( ca. 0.1%) of colonies of survivors of UV treataent
are freed of latent phage, and become resistant, but this yield is so
low as to be very laborious in practice. A number of chemical tests have
been ansuccessful: Phosphine GRN, nitro—aminoacridines, streptomycin,
chloromycetin, aureomycin, arsenite, high temperature. Have you any
suggestions?

Sincerely,

Joshua Lederberg