PUBLIC HEALTH LABORATORY SERVICE
(Directed by the Medical Research Council for the Ministry of Health)

CENTRAL PUBLIC HEALTH LABORATORY,
COLINDALE AVENUE,
Lonpon, N.W.9.

Telephone ; COLINDALE 6041 & 4081.
Telegrams ; DEFENDER, Hyp, LONDON.

 

3 July. 17)

Dear Yosh and Esther,

You may remember that I had found some reversions to the parent type in
some old transduced strains. The particular one involved was a Typhimurium trans
-duced to b-enx with an Abony lysate. The reversion was to i-enx, but J] have now
succeeded in repeating the experiment and have a reversion to be12, I have also
filled in one or two other gapsin the story, but ~ dont have amy old transduced zx
stoaks in bi-phasic strains and would be very grateful if you could let me try so
-me of yours fo-> reversions if y>u have any. I have tried out about 15 monophasics
of mine and Bruces. without guccess. The great difficulty that besets all this
work at the moment is that ~ have not found any way to speed the process up and still
have to wait for several weeks while the organisms mature on Dorset slopes. I sup
-pose that the process is due to the segregation of a heterogenot e, but the proof
of théid has escaped me so far. It does not seem to be speeded up atall by the obvious
mutagens,

& We had Der Max over here this week on his way to a polio conference at
Geneva where he is to speak on phage. I met him briefly at Bill Hayes' but did not
get a chance to hear him on my scientific subject. Bill has al most got his Unit
started but has been suffering from staff trouble since Ken Appleyard is too well
fixed up in theU.S, to want to come over here and Neville Symonds looks like staying
there too. This leaves him withClowes and Ken Fisher,

I am heavily involved with statistical work on the epidemiology of poilo
thesedays but manage to spend two or three mornings aweek on bacteriolog,; and have
had t@ enlist the services of a cohleague to collaborate.

Bruce and Jane are on holiday in France at the moment as I expect you know
Heis pretty uch preoccup ied with the baby when at home these days and is a rare

visitor at scientific meetings. The last S.G.M. Symposium was the first that he
has missed while I have been going to them.

Andy has been doing beautiful stains of organisms lgging but the results
are still too sEcret for me to pass on}

I have good hopes of getting to the Ottawa conference of the Biometric Society
next year, either on the polio work I am doing at the moment or on some other fiddle
that I can fix up with Luca, who is organising one of the sections, Perhaps we might
get over on the Wisconsin slush fund, I am going to Milan on his invitation in
September to talk about statistics in epidemiology.

I hope that allis well with youand that the phase chanze story is wellon the
way topublication, By the way , while trying to find reversidns in a Bowes I isol
-ated a change from a to gp. I have never heand of this before and neither has Joan

~“e Yona, 05 This Vette were
Cree Specially typed an

oh mg watt, .