September 27, 1952
Dear Dr. Boyd:

This summer I had the great pleasure of an extended visit by Dr.
B.A.D.Stocker from the London School of Hy8iene. We worked together
on some problems in the genetics of flagella in Salmonella, using
the technique of "genetic transduction’. In the course of that work,
he suggested that it would be a good thing if our phages could be
correlated into your classification. I agree fully, and an writing to
enlist your cooneration.

We have beer using most extensively the syablotic phage carried
by 3. typhimuriwai Lilleangen's strain 409 (type 22: Aeta path Supplem. 77,
1948), and his strein 85 (type 2) for propagation and assay. I suspect
that Lilleengen's entire collectior mist be deposited tn +ondon, but Dr.
Stocker will, at ary rate, bhyve brceught back our own subcultures. I would
judge that PLT22 (phaze from Lilleengen type 22) is one of your A types.
It's range of adsorption agrees with the distribution of the xIl, antigen,

although it does not necessarily lyse every such strain. I am just about

to try to extend our studies to the genetic capabilities of other phages,

but before doing so it seemed appropriate to comeult with you. It is quite
likely that some of our other typhimubium types would correspond to your

B type phage, but rather than seek to verify this, I wonder if it would not
serve better to use the same cultures. I would be especially interested, to
judge from the published descriptions, jn typhimurium cultures 29929 (for type A)
and C20 and C26 (for type B). If table V of your 1950 paper (JPB 62:501) 1s
correct, C20 is a $ery remarkable phage to attack S. paratyphi A, B, ahd C!

(The antigenic diagnusis given for the latier in the table seems to be in error;
should it not be VI,VII,Vi rather than VI,XII,Vi?). This would be very useful
to us as a means of bridging groups B and C,

In a previous letter, you referged to the discovery pf an indicator for
1404. If your investigations with it have been accomplished, may I have it for
the same purpose-— to exclude apparent non-lysogenic isolates? I um sure that
we are in full agreement that non-lysogenicity in Salmonella typhimurium is
not anly unprovable, but probably gonexistent. Does 1411 remain "ultra-pure"
(in d'Herelle's sense?)

May I close with a final question? Have you ever noticed any symbiotic phages
in Salmonella that would attack rough Souit indicators? Lytic phages specific
for rough are fairly prevalent, of course. McKie (Austr. J. efc. 1934) reported
a number of E. coli that acted on rough gallinarum, but I am looking rather
for a smooth Salmonella carrying such a phage. For my pusposes, it is enough
that the phage be adsorbed by rough cells. If it can be propagated on
smooth as well as rough, so much the betteb.

By way of « pointed summary, my requests include cultures or information
of:
1) S. typhimurium 29929, C20, C26 and indicator for 1404
2) cSalnonellas carrying phages active on or adsorbed by rough
Smooth

Please let me know of any opportunity for a reciprocation of your
cordial fagors.
Yours sincerely,