THE WESTERN PENNSYLVANIA HOSPITAL

INSTITUTE OF PATHOLOGY
PITTSBURGH, PENN’A

¥
December 4, 1948

Dr. Joshua Lederberg
College of Agriculture
University of Wisconsin
Madison 6, “Wisconsin

Dear Dr. Lederberg:

I have your inquiry of November 30, in regard to our paper which
has just appeared in the "Journal of Bacteriology." Really, there
is not very much of any further detail that we can give you about
the experiment in question. In other words, all that happened was
to take a culture heavily seeded with the M phase, inoculate with
S cells, incubate for 24 hours at 37° C, and plate out.

As soon as the reprints come, we shall be glad to send you one, as
well as one of the review that I was trying to get published a
couple years ago when I met you at Cold Spring harbor, anc which
has finally appeared in the "Journal of Immunology." It seems
likely that we will continue some studies in population dynamics,
and we are working rather intensively on the whole problem at the

present time.

I shall be very happy to consult the references that you mentioned,
as I had not seen then.

With sincere regards, I am

Cordially yours,

Kept, Ulealern—

Ralph R. Mellon, M. D.
Director, Institute of Pathology

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