Department of Bacteriology,
London School of Hygiene & Trop®cal Medicine,
Keppel Street,
London, W.Cle

e7th May, 1953.

(Coqey & Mont» ota)

Dear Josh,

Thanks for your letter of 30th April, also for a bunch of
strains, and for copy of stock list,

Paper has now gone in, further amended as you will see from
copy gent you by sea mail. As soon as I get comments from J.G.M. I

will ask for estimate of cost of reprints and let you both know,

I see I was wrong in thinking you did not specifically
define transduction, I agree there should be a name for the general
phenomenon but I think present draft leaves this open 0.K.
Dobzhansky's comment very bizarre,

As to species I have with some hesitation over-ridden your

objection to use of the term. Reasons as follows (1) both Cowan and
Je Taylor consider“hsage O.K., (if) main reason is that the point is
one of nomenc laturé’ only; both current usage (here and I think in
U.S. also) and current international agreement (last Int. Microbiol.
Cong.) are use of binomials and at least implied specific rank.
The current arguement is not about what is the correct usages as of
now, but as to what should be chosen as usage by next intefnational
agreement, I feel sure present wording is clear, which is the main
consideration, and will not, I think, annoy anyone.

I have nearly come round to your feeling that "gene" ©
suggests a naive acceptance of unit with pre-determined borders; I
have worked in some "genetic factors" which logically is no better
perhaps but may as you say sound better, a

vr

}

As to prediction, the prediction was not that ref colar
characters would be linked but that as several independént variables

were to hand, there was probability that some of them might be
linked, As to that I still think your original 2-step aromatic
exacting mutant is better explained as result of additive (or mklti-
plicative) effect of two mutations of very closely linked loci both
controlling one character,

I also picked trails from SL13, but have found them as
refractory as the parent strain, K. has written to ask for SL13 to

look for XIIp, bus have sent it, also two S, paratyphi A O strains
which I can't motilise.
(2)

Am now reconciled to TM,

Felix says the 1930 Lancet paper is the earliest
mention (by him) of 0,901.

Have dropped idea of MGB piece,

The reason I put in double transduction of SW553 is
that I can then say that attempts to do it to other O's have failed,
and thus emphasise the idea that only some Fla, loci are related to
H, locus.

I see you ask for the t-m strains of measured
"mutation"=rate; I will look out and send, also the few new 0
strains I have here, I don't think N.C.T.C, have any more. I will
write to Le Minor, I don't know Schiitze's paper on N.C.7.C. 5045,
what's it about? I never did any more on the plating rwedium for H
and 0, There are several earlier papers on it I think. The apposit-

lon of experimental datum (« bacteriological term) and interpretation
(= genetic term) was in part deliberate, aimed at enlightenment of
medical, etc. bacteriologist£ I have cut out a few and will leave
rest to Editor J.G.M.

, nk Un
We evidently disagree as to hn of "mutation", but
I ht have re-worded in non-commital way.

I have retained L. et al 1951 as ref, for lac, locti,
as it avoids adding another reference,

I agree a-bout antigen B Vi, and have re-worded,

Ie vip apt ipa the nit Loryour note 23:14,
sprint? Fe ae.

Have I overlooked rr

Your note 33, I agree, but don't know how to fix,
better than as at present. Have just looked up New Yorker and agree
again,

SV553 included for reasons stated above,

I think that's all about th paper,
2,4, '

The micro-manip. experiments proceed slowly. A lot of
single cells bkes behave oddly, I am about to repeat with SW541-
lysogenic, but the yield of motilised cells 41s lower. TI am very
pleased with success of very obvious trick to simplify isolation of
motilised cells, that is an adjacent hanging drop of sterile broth
brought just into contact with the drop of treated cells. Even at
37°there seems to be about 2 hourg lag before invagion begins, I
have now managed to pick the single motile cell from a drop with 2104
non-motiles, all progeny of 1 motile cell, and got it to repeat the
process, Also now 4 instances in some 40 single motile cell isolat-
fons of the equivalent of 2 or 3 trails arising from a single cell,

fog, OV te
(3)

 

and have confirmed their occurrence on semi-solid agar, using both
SW541 and SW541 lysogenic as recipients. K

More later,

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