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274 Lyon Laboratory

PEPsATMEWT OF PU YSteLeeT
SivIS0ON OF CANCER BEOLEGT

“March 26, 1957

Dr. Joshua Lederberg
Department of Genetics
University of Wisconeia
Madison, Wisconsim

Dear Dr, Lederberg,

I have recently become interested in the *petite™ of B.coli B
that Weed has induced with copper some time ago (7 ect 67, ey, AGhL
At first I could not duplicate Weed's results, in epite of the fact
that I follewed the instructions given in his paper exactly, In tis
moantine | fonnd, however, that by raising the copper concentration fro
9 to 15 x10’ MI get ca. 60% littles, and I an trying higher
concentrations at the soment in order to eet 100 $, The littles I se: ..-

At any rate, I had been locking for Weed's present address al!
over, without suecess, Dr. Weed must have heard about it, becaues
yesterday he wrote to me from Jangor, Maine, He suggested that

@ I get in touch with you, as you had a graduate student and a fellow
continue his work, Did any publications come out of this? If s>,

I would appreciate it very much if you would let me have then,

Also, if you have any unpublished material or information you could

let me have I would de most grateful to you. Did you do any work

on the anagymatic basis of this mutant? Do you have any hypotheses «s

to the mechanism of the mutation?

YY

Thanks a lot for your help!

Sincerely,

Herbert Hirsch

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