Dear Horton;

I uo del.Qhtad to hear of your subetantAal progrmcrsr on Us mum-v5rulenee
problem, Are you sure that nothing can be found in vitro that would parallol
the a.nimal wcpd.mmta?

Saybaluti made up that quotation-- 3 MWW add it, thou& 1 might w.ll have
want it.

Sorry to have to preua you 80, but what 1 wanted ea a "defWtion" of a lytti
variant was Just rhioh phage and kdfeator system you had in hand. I may ha-
omrloukksd this in an earlier latter from you.

the Xou may be intmM6d in ram, mm on ly8og0nl8ation/tran8du~,~n. Thirs time
uopxud.aoa aonemrna the imidsms of lyeogrrniaity in Qal?Jk (added) rrrrd
531 C&al. Fla- ($ranaduationa,from @l.la-) mleated on F3QB CU. The w
the added Gal ware 3 Lp+143 Lp:; the tramsinduaad Gal.+ wre 18 Lp* :
`%a only trouble is that we do not know what lim%ta the incidmue of 4sb@imL
crlty in this apate% I have em other expsrlmanta %n the works uh4ra thy'
llaiting factor ir the amount of phags. ThQ correlation WWBJW already secure.

TOW OrgPtl& nOtrb UOM tifSS a6p Kphweo = ttfp = a should, I takRl It, bar
intwpretsd as %O/&uta, and not 8O/ssoond or 8O/hour, Zn the expmrrion
V = V ewkb. Dam finally pulled out an FA Serb he had rtarted agee ago. It
titra&d, roughly,to about sO/sLin.   I havml * t so far aheaked your ooapariaon
of FA and phage.

I was inprrr~d to me whether one crould not break up the action of the
prsmmd Hl "8% uoeglex in tha, linked trmsduetion by mana of UV. I was
rat&w surprfmd to f And &hat the imotivation of transduotion wm almost nrgli-
gible (following We initial activa$isn) rrtnn with trmemdoua dossr. With suah +
exposursa ad 20 f&n&es (aiu! ) at 50 ea. # phago tftmw of about 100 - loo0 /f&l
are msooiated with approxiaataly equal or higher tramducrtive acrtivity. 11~s
looked mat at Qal+ from SW-666, using phase, 22B, but Fla* behaves ri.&.arly,
and one experiment with PLT22//2 on SW435 /D(o) gave eseentMJ.y eimllar msrult,s
(thir 14 still tiubating). One oan sarily oount plaqum and CW+ on kha mum
plate. I heventt tmted the lysogenioitg of the lattm 10 far. Thlsreem to be
diacropant with your pmvioue findings, but I oen't find any reaord of them here.
This knight bs weful in praoticm with other ~&ma--e.g. your virulent mutant,

#ft& Larry's help, I'ni also look&ng 3&o FA in lwoffatea. SW-666(PLT22B) mms
to be working mderatx3.y ml3.j mst other clya~tems not. The phage 80 far bars general.
tranrsducling aottivity, but I'll send you the details when they're worked out.

+udoubt&ly overastfma~d owing to         Joshua Ladsrberg
the possibility of rnultiplieity reaotivation.         '
The fnaqtivatfon ourve definitely flattma out as mcpeated on this batsisl.