FEDERAL SECURITY AGENCY
U.S. PUBLIC HEALTH SERVICE

 

IN REPLYING, ADDRESS THE

Toc. Research Laboratory,
411 Bast 69th St., New York al, N.Y.

June 6, 1949.

Dr. Joshua Lederberg,
Department of Genetics,

The University of Wisconsin,
College of Agriculture,
Madison 6, Wisconsin.

Dear Josh:

Werner and I are leaving Sunday, June 12th, to
drive to Pacific Grove where we are taking van Niel's course,
We are planning to bring a passenger to Madison, probably
arriving on either the 15th or 16th, and hope we will be
able to spend a couple of hours with you then.

I have done some recombinations with the strains
which you kindly supplied and am pleased to find that it is
Just as easy as you said it would be, Almost all of the
recombinants from 58-161 and W-677 were mucoid, while those
from 58-161 and Y-10 were not mucoid. At first we got "atti, |
excited at what looked like recombination of our-‘multiple
mutants too, but since we were working with a double mutant
requiring PABA plus proline it turned out that we simply had
proline independent reversions which were being fed PABA by
their neighbors. Further experiments have shown no recombina-
tion within our strain or between ours and yours.

If you are going to be in Madison when we pass
through I look forward to the chance to chat about some
aspects of this problem,

With best regards to Ssther,
Sincerely yours,
IF oprece.
Bernard D, Davis,
Senior Surgeon.

BDD/h1