Re: Miroslav Hill responds

From: Derek Gatherer (
Date: Fri 02 Dec 2005 - 11:16:21 GMT

  • Next message: Derek Gatherer: "retransmit"

    Exactly, the selection medium simply gets living cells dumped in on top of the dead ones. The same flask is used, not a clean one. In the unselected medium there is passage (which means spinning down cells, taking an aliquot and seeding it into a clean flask with fresh medium). So tell me then, where's the control? What is being compared with what?

    At 20:46 30/11/2005, Dace wrote:
    >Derek,> From: Derek Gatherer <>>> Before you
    >start fulminating, Ted, I suggest you re-read Hill's>
    >paper. (bottom of p212 and the first paragraph of 213). Then
    >reread> his reply.I don't see the contradiction. In response to
    >your question, Dr. Hill saidthat at each passage the culture was
    >divided into two subpopulations whichwere both placed in clean
    >flasks. Here's what he wrote in his paper:"Briefly, cells in the
    >logarithmic phase of growth are, at each passage,divided into two
    >unequal samples and subcultured by seeding the large sampleinto a
    >selection medium and by growing the small one in a parallel
    >culturewithout selection."No contradiction there. Perhaps you were
    >thinking of what he wrote next:"The cell monolayer in the selection
    >medium, when depleted, is periodicallyreplenished by the addition of
    >fresh cells from the parallel culture."This is a separate issue,
    >having nothing to do with splitting the culture ateach
    >passage. Since the exposed culture is depleted by the toxin, it has
    >tobe replenished with cells from the unexposed culture. Are you
    >suggestingthat this somehow contaminated the unexposed culture? You
    >have yet toexplain how Dr. Hill's results were compromised.ted> At
    >21:26 27/11/2005, you wrote:> > > From: Derek Gatherer
    ><>> > >> > > Just ask him. I think you'll
    >find the reply interesting.> >> >As I expected, Dr. Hill says the
    >cultures went into clean flasks. I> >refrained from passing on your
    >question because, frankly, it's insulting.> >Of course he used clean
    >flasks! The man is a highly respected scientist.> >He's obviously
    >not going to put his cultures into used flasks.Fortunately> >I
    >didn't have to send him your question as he found it himself on the
    >web> >and graciously passed on his answer to me. Here's his
    >post:> >> >Dear Ted Dace,> >> >Incidentally, I have stumbled on the
    >question by Dr. Gatherer who wrote:> >"What I'd like to ask Dr Hill
    >is, when he splits the unexposed culture,do> >the cells to be
    >exposed to the agent go into the same flask as
    >theprevious> >exposure was carried out in? Or is the exposure
    >culture set up in a clean> >flask each time?".> >> >The answer is as
    >follows: At each passage, the cells are split into
    >two> >subpopulations. One of them (a small one) goes into a clean
    >flask with> >growth (nontoxic) medium and the other one (the large
    >one) into a clean> >flask with toxic medium.> >> >Dr. Gatherer can
    >send next questions directly to me on my
    >address> > I am not used to forum discussions on
    >the Internet> >though I read my email.> >> >Sincerely yours,> >Dr.
    >Hill> >==============================================================
    >=This was distributed via the memetics list associated with
    >theJournal of Memetics - Evolutionary Models of Information
    >TransmissionFor information about the journal and the list (e.g.

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