: Telephone | Harpenden 4671 (10 lines) Railway Station: Harpenden (Central)

ROTHAMSTED EXPERIMENTAL STATION

| (LAWES AGRICULTURAL TRUST)
| Dire@or: SIR WILLIAM G. OGG.

Head of Biochemistry Department : HARPENDEN

: N. W, PIRIE HERTS.

PLEASE ADDRESS YOUR REPLY
TO THE WRITER BY NAME.

, 12th April 1959

Dear Lederberg,

I seem to remember that somewhere
you com-ented briefly on some experiments thet
you thought were on a bacterial virus but that
you soon found were in fact on -OH ions. These
simulated in many ways a virus infection and you
commented on the difficulty of freming a definition
of "virus" that could be relied on to exclude euch
: en effeci automatically, I cannot now find the
: passage.

Can you remember where this appeared ?
Alternatively, if my memory is playing false and
the comment was not made by you, do you remember
: who it was by.
:

| Please do not go to any trouble over this -
| I only want to use the point as an analogy. But if
: you can remember the reference I would be grateful.
: Probably it is in one of the reprints you so kindly
cend me but, if s0, someone must have "borrowed"it,

Yours sincerely

Vet Pos