August 9, 1946.

Dear Dr. Dubos:

In connection with our experiments on the occurrence of recombination
genotypes in mixed cultures of bacteria, I am trying to review past experiments
on 'hybridization'of bacteria. Your monograph, The Bacterial Cell, his been
highly useful in this project. However, there seems to be an implication on
p. 181 that you may have other references ka which you did not think impor-
tant enough to record:

' Although there have been isolated reports of successful crossing,
most workers who have attempted to cross related strains have reported only
failure...'

Only three papers have come to my attention on this aspect:
Almquist,1924, Sherman and Wing 193@ and Gowen and lincoln 1942.

I would appreciate it very mich if you would send me any other
references of such experiments, whether successful or not.

Very sincerely yours,

Joshua Lederberg.