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PRINCETON UNIVERSITY
| PRINCETON NEW JERSEY

July 7, 1943

Dear Sonneborn:

Il am sorry not to have answered your letter
earlier, Do not think I did not consider very care-
fully the objections you put forward concerning the
vever on virus-resistant becteric,

I understand that you do not object either to

the experiments, or to the methemeticl the ry, which,
as you correctly remerked, only shows thst resistant
are grouped in families, ana in particular in su¢h
4 way aS can be vredicted on the assumption that every
‘time a bacterium is resistant to virus, all of its
‘offsprings will also be resistant. You feel, if I un-
Gerstand correctly, thet the possibility exists, that
occaSionaly certain bacteria find themselves in such

a physiological status that an ettack by virus is
followed by resistence (inheritcble, et least in
asexual reproduction, which is the only existant in
bacteria), Moreover, this perticuler physiological
status should appeer in femily sroups. Let me state
thet, if thés membitims physiological stetughere
alweys inherited, so thet all offspring of 4 cell
whien has been once”potentially resistent"are uw¥so
potentially resistant, ,f,wouls be reaay to eonsider

it identical with oury®fSSumption. It would still be

a cese of stable inheriteble chanee, aid it is immaterial
whether the physiological property of “faving CR LLLES
the sensitive receptors for virus only aprears after
the action of the virus. Th@s is seakd in our discussion,
with the reasons for which we believe that the physio-
logicel change takes place before end not sfter the
action of the virus. The other nossibility th:t I

see, which would follow from your sugzestion, is that
the physiological stetus which produces resistance

is not inheritable, but only oceasionsly present in
certain families{I should say clones), and the stable,
inheriteble change is produced by the attack of the
virus. Besides the fact that this possibility is a
litkle unpleasant to conceive in the case of « change
which remaing steble over innzmersble fenerations, .
I think it would be quite neeculiar that swekhwe thes
condition should be present in such « way as to give
the same distribution of resistant becteris as pre-
dicted on the besis of the theory, eccording to which,
I repeat, all offspring of a baeterium resistant to
virus ere elso resistant. The venishing away of the
clonal, temporary resistante (or predisposition to it)

“ssw Utogsuuog

Azerqry ATITI *‘quew.zedag sqidtazosnuey
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Buetpuyl ‘uojSsuTMooT, ‘Ay Tsaaatuy BUBT PUL
 

Department of Biology

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Quoted o
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PRINCETON UNIVERSITY
PRINCETON NEW JERSEY

2

should show up, I think, as a Lfsé change in
the distribution of resistant bacteria, I am soing
to discuss this point in eorrespondence with
Delbruck, and hope to be able to find a more
convincing, quantitative answer. I do not have with
me the abstract of your paper, which remained in
Bloomington. I would like to know where it is
published, If you ere not too busy, and want to
waist more time with me, I would like very much

to hear more objections, particularly, some other
of the dtiterpretations which you consider possible,
besides the one that I took the liberty of attri-
buting to you in the preceding part of this messy
letter, I am scered at the idea that I am going

to reed it over in & moment, and probebly find it
incomprehensible.

I got word from Zirkle thet they cannot wait
any longer for my clearance to errive from Washington,
therefore I am going to be beck in Bloomington in
September. I got the respirometriec techniaue well
in hand, and hope to set some more insizht in phage
growth some day.

After an ewful heat spell, we have started
living again. Princeton is almost as boring as
Bloomington, but New York is within easy reach.

Best regards,

a

BG ii aici ant Sea ee ea alte tena arate gedaan, aysiu d adeai le ave bead

‘Ssul UTOgsuuog

AIVIQTT ATTTI Squowyredeq sqydtazosnuey]
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BUBTPUT SuoPPuUTWOOTA *‘AYISTAATU_ BUBTDUT