October 18, 1952

Dear Dr. Kauffmaan:

Thank you for your letter of the 11th.

I appreciate your suggestion of the desirability of hybrid types
constructed to carry rare 0 antigens. Unfortunately, for the present»
we are ably only to work with cultures in groups B and D, carrying the
xII, component. Our current investigations are designed to extend the
scope of the "hybridizations" to the other groups. When and if this is
achieved, I will be pleased to be able to consult you for further develop-
ments.

After reading Edwarda' 1946 paper, I realize that monophasic strains
have been isolated for acat of the major MN complexes, excepting r. I have
recently constructed a hybrid from monoghasic S. paratyphi Bx S. heidel-
berg which should be r—-. If the r phase does prove tc be monophasic as
expected, and not r-1,2 like S,. heidelberg, this strain may be useful.

I am expecting to visit Chamblee in a few aionths to learn some more
of the Praktik of Salmonella diagnesis from Edwards. In the meantime, I
shall be concentrating on extending the theoretical foundations of the
genetic "transduction". I am most gratified at your interest in this work,

and will endeavor to keep you fully informed of it. .
‘ ! [ o fe h : C7
Youfs sincerely

ie
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