Nave you any word on the be:& way to order the qmoial glaraeware
and pumping-co&trol a&up on the chemostat": tie'11 have to write tho
ordar by early naxt wcsek to ham the fwtde char.

Kim Atwood's paper on periodic selection ceme out in P;lAS last week.
This is ths one I talkkd to you about fn Chicago. There have bean D. few
minor improvmmnts from th6 me., but the basic argument fa still the
Urn%. 31e'll have a good opportunity to argun this out at CSI: in Jum, but
f wonder whether we cpuldn'd diooum it before than.

Rbts noat important point tadem to be the argumnt that periodic sel.8~
tion sots ~38 a perpetual eslf-purif'ying mohaniern which can act to
protect m evolving populatim fr F. the daletmioua affaoto of mtntion
pmmure9 whi<zh, presaanably, favors auxotrophy over zrototrophy. I can't
mm how this can be a ramlt of a mmpling m+mncPs whiuh doeca not
dioortiir,inute bstween wild type and mat.& allel. K&s mmms to fool. t&m&
the non-dfmmdxt h&are of the sampling procseas which ho snv3.s%goa could
ha* e such an erract (i.e., that the unit of empling ia not Z GQ& b&t
lQQO>. To ny j&d, tha effecta of mmh oQpnpl%ngs might bc 8 datiatiton
or rather fluct&at$.on from the expaetad coumms but that ths population
till continue to tend towards aquilibrim at an a?faetivc rate nut gree.tly
dif.%rant from that anticipsated wfthout auclh selection. EIYT will. probably
urgua that hZs sxparimmtml populations come to 5mx1 oort of oquilib~im,
but thin nay am-m that h5.a explanatory theory is incomplat~.

I've besn hoping th:& you and SzilLard ml&t \m worlrlng out a moothtsd
out theory for the evolution of populntions unbar KCA'B postuldm. 1s
thara any special difft$&%ty attached to thie?

%a wsather hae been feirt3 of raw, but when it gets wamcr I hope, that
you anlf Jam will remmber your promise to drive ?ortln with WG for a cot@ls
of day83 touring.