April 21, 1977

Sir Peter Medawar, CH, FRS
MRC, Clinical Research Centre
Transplantation Biology Section
Watford Road
Harrow
Middlesex HA1 3UJ
England

Dear Peter,

   Everybody would be delighted if you could give a seminar here
after your visit to San Francisco in late November.  wt3 would pay
the extra air fare, for two, which this side trip would entail and
all your expenses here, including hotel accommodation, for two. We'd
also suggest you stay two nights here so that your visit isn't too
much of a rush.  In addition there would be a very modest honorarium.
I suggest you write again to me, at this aadress, in mid-september
(when I'll be back from Denmark) and we can then start to plan the
exact dates.  It usually pays to consult the airline schedules before
being too precise and these change from time to time. Naturally you
could break your journey at L.A. either on the way here or on the way
back.  Incidentally since you are going in any case to visit three
U.S. cities there may be a very cheap air fare for doing all this if
you book well in advance.  If this seems a sensible thing to aim for
we should perhaps try to tie it all up a little earlier.  I'll ask
my secretary to look into it but as somebody else is paying you may
not want to be bothered with all that.

   Thank you for the papers about fetal antigens. Of course I've
known for some time about the possible connection because when we
get interested in embryology Sydney, who had picked up the idea,
I think, from something Boyce had just done, wanted to cultivate
tumour lines to help us study fetal antigens which, from many lines
of work, especially on Drosophila, we both thought to be important.
(The analogy was the use of myelomas to study antibody molecules.)
I thought it a good idea but I was against doing it then because I
thought it would be too much work for Sydney to take on in addition
to getting the nematode system going.  The irony of it is that, due


Sir Peter Medhwar            -2-

April 21, 1977

to Rothschild, our division at Cambridge now studies the system in
reverse.  That is, th8X8 is a small section, headed by Ed Lennox
(now migrated from the Salk to MRC, Cambridge) who are studying
the chemistry (i.e. the exact chemical nature) of the new surface
antigens found on chemically induced tumours.  We faintly hope all
this will then spill over onto the work also going on in Cambridge
on developmental biology.

   I haven't yet read the "magisterial review" by Coggin and
Anderson but it seems, on general grounds, rather likely that to
get a tumour you need a new surface antigen of some sort.  Surface
antigens ax8 probably not easy to prOdUC8 by any old process and
the cell would do well to use one that has already been evolved
to sit nicely in the cell surface.  Fetal antigens are obvious
candidates for this.  If one adds that chemical carcinogens almost
certainly work because they are mutagenic then, in outline, the
whole thing seems fairly clear.  It's when one gets down to details
and asks nasty, precise, questions that on8 sees that, so far, it's
all a bit flimsy.  But very interesting, all the same, and I cer-
tainly feel I should know more about it.

  Nice of you to think of Panspermia for Vogue (curiously enough,
we did originally consider Playboy) but I think not at the moment.
I have faint plans for a popular book on the subject, since every-
body enjoys hearing about the idea, but it would really be a peg
to hang ideas on The Origin of Life, The Structure of the Universe,
The Nature of Science and other Larg@ Topics.

F. II. C. Crick
Ferkauf Foundation Visiting Professor

FHCC:kv