June 8, 1956

Dr. MW. R. Pollock
National Institute for Medical Rgsearch
Mil] Hill, London NW 7

Dear Dr. Pollock:

Thank you for your message of May 31, and for your trouble in sending the
penioillinase preparation.

I would like to renew my request for cereus 5 and 5B, but with so many
parties involved, I should give a candid explanation so there will be no misunder-
standing/ Since ay last writing, I think I have definitely interested Professor
Johnson in following up the chemical angles of some recent morphological findings
on the m/o of penicillin. [I hope to be able to send you an ms. on this in a few
weeks}. It seemed to me that it would be a definite economy to pursue these
studies with bacterial straina that have already been well characterized from
other viewpoints. It would be a definite advantage to us to use a penicillinase-
negative bacillua, if it is otherwise amenable, and possibly make comparisons with
penicillinase-positive autants. However, Johnson tells m that he would inevitably
have to make a preliminary study of fixation. We would be delighted to take advan~-
tage of your own data on this point when they are available. X agree with Johnson
that we should not accept cultures on any conditional basis that might limit bas
freedom of thought ani action, as there is no telling where (besides up the garden
path) the pursuit of a problem can lead. I am deliberately exaggerating the potential
Assue, ami I want to assure you of my cordial appreciation for this material when-
ever you decide that it would be appropriate to send it. There is no great urgency
here as there are a number of preliminaries to be completed before the main problem
is reached, though 1t will be convenient far us to assemble a variety of strains
for cursory examination.

I was moh interested in your remarks about the possible prevalence of
penicillins in nature; what will the patent attorneys think of that?

My wife and I are hoping it will be poasible for us to visit Australia next
epring, and if the finances can be arranged, to mike a ciroumglobal tour of it.
The entire scheme is very tentative now, but we will neglect no opportunity that
may arise to vis&t you and a&hgrother British colleagues and friends. Professor
Pontecorvo who his been visiting us recently will probably be one source of

information on our plans, having offered his good offices on the matter of an
visit to the UK.

Yours sidcerely,
A Py,

A
) fi

hefl. ft oe “ ’ sr
WAL r
‘Joshua Lederberg
i Professor of Gene tics