4/7/52

Dear Hayes,

hank you for the copy of your letter to Lederberg.
TI have been very interested by your findings; as to the filtra-
bility of F, it has 5 prised me somewhatnbecause I have got been
able to get sterile filtrates musing collodion of 0.74 “PD (of
German make) even under as little pressure as 80 mm Hg. The fil-
_tratessai I cot were turbid, Using filtrates with smaller ?D
they were sterile but had no transformins acktivity. Lederberg
writes his wife has got some indications of P+ activity in phage
L.satess have you tried this way ?

I have written to Lederbarg and sent az copy of the
paper fo r JGli, I therefore hope that 1 shall be able to let
you have it efore the meat r8é the month ; deo you think you
could send XRuxe manuseript/over bY the léditors,after having
made tue use of it which you may like,or should I better send it
to tne Sdi tours directly? In the recommendations to authors,

JGM edito rs ask that contributors from outside Sritsin name a
person to correct proofs,ho has do micile in Ct.Britain. In
eise they ask me specifically for dving so, can T name your

p erso n? Sorry for the troubles by * do net see who else could
have tue competence about the $a ywhich you have.

T am really working Lard,but little of this goes to
the problems T am more interested in. IT huve a deal of organi~
Bing work beside the one,which you know,sand which is almost
finished n ov,

It will be nice to see you again 2t Pallanza,and hear
of your lnt est news, is T wrote you, you can yse as hong as
40' for giving your peper. ‘8 to myself, I may” ther five the
p aper,of which you will see the copy for JGM, or else just
say a few wo rds in the disoussion of your. paper,as there will
pro bably be a number of overlapping things, which people attens
ding the meeting need net hear twice. I should give you priori-~
ty inax speaking,so as to leave you free room and time; as I
shall have to take care of local arrangements, I would not mind
giving up entirely my paper.

I shall be away from the 20th of July to approxima-
tely the 10th of ‘ugust. I should attend -as an oussider!?- the
Biochemistry Congress at Paris. For the reat of the time IT
shall ve in Milan «yhere we are experiencing 2 very hot weather.
Wi th beat greetings to lirs.Hayes

Yours sincerely
>.S. In repeating so me of your experinenta with streptomycin,
I could not obtain good ykeids of prototrophs with"sterilised"
cultures, «Ay which pH did you let streptomycin act on bacteria?
dlave you checxed whether any other agents can suppress colony
fo ruing capacity,without altering prototroph formation? I have
(80 we slight indication ihat beat (60°, 1/2 hour) may do so.