June 2, 1948.
Dr. Philip 3. Cowles,
Tept. Bacteriology,
Yale University Medical School,
New Haven, Connecticut.
Dear Dr, Cowles,

Some rather suevestive results bearing on the occurence Uf genetic
redombination have cone up with somes of Purkholder's [, subtilis
nutritional mitunts. They cre,however, suite inecnelusive, and sill remain
so untii IT have some edditional charseters at my disnosal, In the
E, @oli work, phage resistance worked very well. I yonder whether sou
can help as out at all to accuire gone aubtilis phases. The organisa
is tha so-called Marburz striin.Do you have any on hand, or dan you
refer me 4 any other worker to whom I might apply?

Yours sincerely,

Joshua Lederberz
assistant Professor of ‘enetics.