October 31, 1949.

Dr. Bernard Davis,
‘Tbe Reasearch Labs,
431 E 69 Steeet,
New York 21, N. Y.
Dear Bernie:

I don't know whether I'l] see you in Chicago this weekend,
but I thought I'd better write concerning the "Bacterial Genetics
Course" at Caltech. Beadle has probably already written you something
about it. When I received your letter, I had already begun corres-
pondense with Berkeley about visiting Cal next summer. Beadle wrote
nothing for some time, and in the interval, arrangenents were prac-
tieally eompleted. I just wrote to Cal that I would accept a visiting
appointment which would run from August 1 through the middle of Sep-
tember. Under the circumstances, it is very doubtful that I will be
able to participate in your proposed course this summer, even if it
were held early. However, I hope to eee Beadle in a few weeks, and will
discuss it in detail with him. If the course is going to be repeated
in 1951, I think that I will be glad to go in on it.

Thanks for sending the mutants: there was more there than I could use.
No information én them yet. I do think that we have picked up another
crossing strain of E, coli, and a couple of Salmonella species likewise.

Sincerely,

Joshua Lederberg

That was a very interesting paper in Experientda (Lu showed me MS).