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“SEMAEIMO DELEANTL”

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Direzione Scientifica . | Milano, ..... 16/3/53 Lc eessvettuutttttvetettsevestiteeeseisen
Dear Joshua,

My laziness in answering your letter of february 2lst (actually caused
by the fatigue of excessive corresvondence to which IT am subjected by
Congress duties) has been compensated by the fact that now regular
order in our correspondence should be restored.I have,in fact,in my hand
your letter of March 12. I hope this letter of mine will not suffer
again an undue delay. In this place, correspondence goes through at
least four hands before being actually mailed,and it is very difficult
+o understand who is responsible for the delay. However 7 shail try to
make sure that this one at least will reach you in due time.

I have not sent to Chain the letter you enclosed, because it was outda-
ted by Chain's letter to me, In fact, Chain's letter,dated Feb 2list,
inviting me to give a paper,said afterwards . " I understand from yr.
Eagle that you may like to give a joint paper with Dr.Lederberg.It was
originally intended to invite Dr.Lederberg,in addition to yourself, but
it appears that it may not be possible for him to come to Europe this
year. Perhaps if Dr.Lederberg wishes to send in a communication of his
own, in addition to the joint one with you you would be prepared to read
it for him." I have answered him on the 23rd :"Dear professor Chain,
thank you very much for your letter of february 2lst,and your invitatior
to give a paper inthe Symposium on “rowth Inhibition and Chemotherapy,
waich I accept with pleasure. I shall take direct agreements with
Jeshua Lederherg ,who I understand will be speaking on a similar topic,
in order to share the task in the best way. T-would certainly agree
to read a paper on Dr.Lederberg's behalf. Fouts etc." In viww of this
former eachange of correspondence,! thought your letter might have caus:
sed confusion - although I wish to thank you for your support in the
matter. Since Chain waemed,already at that time ,aware both of your par
ticipation as far as papers were concerned,and of the possibility that
ygurtey be unabze to be physicxally present, i thought it best to keep

& letter wxkkxma which T am sending back enclosed. Moreover,the date
for sending the manuscript,in Caain's letter to me,is "during the month
of April" which leaves axkskigr us some more time than April lst.

I hope you agree on allxthis . Concerning the paper itself, I am
waiting for your notes. My third paper on the subject was given at the
Congress of Biochemistry,and was published by Sedes,Paris; no reprints
were given,a fact of which I was pleased,because the manuscript was as-
ked very late and went in without figures,bibliography and subtitles,
and is therefore almost useless to readers. However,. am sending it
by airmail,under separate cover,together with the microfilms you asked
for.Could you sand back after use (no hurry) the pages of my article,
as it is the only copy I have. Unless you have good auggestions,it is
P.S. Thank you very much indeed for your and “sther's beatiful

photogtaph. It was a kind thought indeed. I shall try to get one
of mys@lf to let you have an ddvanced sample of myself before we
actually meets;1 have none available at the moment. - Cultures hit

yet sent ,7 am afraid ! Stayed on ay desk for a week and were di-
scarded being too old.

probably better to excluce, from our joint paper,the park last part of
my Parisian paper concerning mechanisms of reshstance. ae

I was greatly interested about your news on selection for F- through
motility, SM"Killing" ( I strongly agree about hyphens) ,and Hft. I
have nothing interesting to report. I have concentrated mostly on F+
transduction.Casein hydrolysate (which aminoacids?) is enough for tran-
sduction to oucursapparently,F+ cells need not mpltply to yzeld F4,
While xkexusz F- cells are more infectahle when in stages of activity;
but these conclusions are still tentative.I am ,though with little en-
thusiasm,making kinetical calculations;it would seem that browniaa mo-
tion might be enough to explaiyg F+ transducvion by collisions.But T
feel rather uncertain about using classical formulae for brownian mo-
tion of bacteria.? should be interested t penew Nelson's approach to
the problem ,which he has only sketche aya ane fis” fenetics paper.All this
is preliminary to an experiment,to test whether F+ behaves as a pempe-
rate phage or not,i.e. whether it is produced in bursts : using micro-
drops containing one F+ cell and many F- cells,and testing the distri-
bution of transductions among microdrops. te

Hayes : I have not yet answered any of his lett § since December,
and think it unnecessary to send him Hfr,since his/works well,and he
couldyget what he wahted,i.e. an Sm-sensitive Hfr(by recombination !
5-10% recombinants stated to be Hfr by nim) to test the Sm ertect on
it(which he has found ). From his data,it seems that his Hfrtpchaves
differently from mine,though only in segregation of Hfr. H hope you
will meet him at CSH ; he is a very pleasant person,and even if he has
somehow messed up the situation by unnecessary hypotheses,I envy him
his uninhibited approach to the problems . I find my Mendelian back-
ground more often hinders me than helps me in bacterial genetics, though
it is clear that it is me and not Mendel who is to hlame for this
reason. — I have meanwhile answered negatively another request of Hfr;
copy enclosed for your information.

Calef : he should know a good deal of bacterial genetics techniques
by next autumn,but I doubt that his English will be tolemmb&e by that
date. Buzzati thinks there would be no harm in Calef waiting another
year before going to America ,and I think it best if Calef withdraws,
for tne time being,his application,which will probably come again in
question next year. If however,he will stili be interested in bacterial
genetics,as likely,no doubt he should try to spend a time in your lab.

Herneditgs reprints received.Thamk you very much. I hope JGM ones will
be soBgn available. I strongly hope to see you next sumner,unless there
is a better chance to see you in more profitable conditions. You would
always be welcome to this laboratorypand we have no sevious room diffi-

culties. Yours Doves ea they vtnk IT paw eG ath ary t
porder rt « 4 thr, ?

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