26/6/52.
Dear Dr. Lederberg,

Thank you for your letter of 19th June. I am glad to
hear that you are still interested in the L forms. But you are mistaken,
for I have been able to verify reggneration from E. Coli B + phages Te
and 13. It occurred in the L form and was then transformed into bacilli.
I have cultured L colonies from little white granules that turned up
in the filtrates after about three weeks. This happened several times
with one batch of broth, but I was not able to repeat it later with
different batches of broth. I am convinced that it is dependent on the
constitution of the broth, but have not the faintest idea which
substances are essential. I am a bit doubtful about Hemophilus pertussis
and would have more confidence in work with Salmonella or Coli.

The fusion figures in the K1l2 strains, I have no
doubt,are precursors of L forms, Fusion means flowing together and may
not be connected with anything sexual. It may be for protection against
some adverse conditions. I have recently observed wonderful fusions in
a Micromonospora , occurring (the fusions I mean) in very dry cultures,

IT am still very much hoping to come to your
laboratory, but I am not planning anything just at the present moment.
In regard bo a publication of Prof. Tatum and you, I should like you’
to mention my negative. attempt to connect up morphclogical structures
with the occurrence of the prototrophs. I think it should perhaps be
mentioned somewhere. .

Yours sincerely,

£. Nekel