SLEGEDI ORVOSTUDOMANYI EGYETEM
MIKROBIOLOGIAI INTEZETE
Igazgat6: Dr. IVANOVICS GYORGY egyetemt tanar

Institatom Microbiologicum OZ cee Q , ce 3 Dec emb er 1 g 2 6 .

Universitatis Medicae Szegediensis,

CsNyV (kg) 54-4000

‘ Szeged, Hungaria

Professor J.LeDERBERG,

Depertment of Genetics,
University of Wisconsin,

MADISON 6, USA

Dear Professor Lederberg,

I wish to be apologized for being late in answering your
kind letter of October 12, 1956. The fearful and tragic events
in Hungary absorbed all of our interests. Now, I am getting re-
cover the deep psychic shock caused by the latest incidents.

I agree with you in the question of terminology of 5-R
variation. No doubt, the discovery of S-R variation of enteric
bacteria was a considerable success ena a ;- reat part of confusion
concerning the varietion of tnis group of vacteria has been eli-
minated by the S-R notation. This notation might useful even in
the case of some e capsulated bacteria. There are, however, some

cases, e-g-ile tuberculosis where the S-R not. tion is not justified.

That is why I felt uncertenity when I wanted to designate somehow
the mutation of Bacillus megaterium. I am very greatful for your
letter in which you helped me to overcome my hesitation how to
term the muiation of Bacillus megcterium. I dropped the §-R no-
tetion in the final draft of my manuscript which will be published
in Zbl.f.Bakt.Orig.I. I used similgr symboles to thet you were
kind to propose me. The symboles are based upon the antigenic
sturcture of cell wall and the pahe sensitivity or resistency
of variant.

you were as Kind as to refer in your letter to thet there is
some interest that "rough" isolates are also non-motile. I have
tired to select motile "reversion" from these cultures but my
all attemps failed so far. I had an opportunity to met Dr.Stocker
at London this spring end discuss about this very question. The
flageller transduciton by temperate phages is out of question
for the "rough" isolates are entirely resistant to phages.
. The note which you enclosed to your letter is extreemly
interesting. I was always of the opinion thet the L-form are
not a special live-cyclus of bacteria ana tne whole mysterious

business of "filtrable form" of bacteria is coming off the misin-

fy
terpretation of experiments the results of which were due either
to gome technical error or due to an "denegeneretive" develop-
ment of cells. A part of the Sovjet athors and their young, and
eager followers here still of the opinion that there is a non
organized form of "living material", and this form of life, elso
the "filtreble bacteria". after downfall of Bosjahn, Lepesinszkaja
and Lisenko, this theury of "filtreble voacteria" is not much
attractive “> the people who eavocate it us it was vefore. Your
observetion and interpretc tion of the neutre of L-forms, there-
fore, is more then mere scientific fact; it is "philosophy".

The adresses requested by you: J. VADASZ, Egyetemi Sziévettani
Intézet, BUDAPEST IX. Tlizolté utca; Prof. J. HORVATH, sagrértudomanyi
Eeyetem, GODOLLG, Hungery..

With all »cod wishes for the new year.

Yours sincerely,

$b Teac

Prof.G.Ivdanovics