Parade! Stand easy. Relax folks this is my last entry on this subject. Brian, I think we have reached a workable conclusion to our epic. Your analogy has the troops heading for the assault course of the blood brain barrier and five years of soldiering taught me to avoid assault courses whenever possible. To summerise. 1. a body of troops is sent to tackle the assault course. 2. troops are marshalled on a parade ground from where they are to tackle the assault course. 3. whilst waiting half the troops faint in x mins. 4. half the remaining troops faint in the next x mins and half again in the next x mins etc. 5. at the same time an unknown number of troops are successfully making it off the parade ground and over the assault course. 6. The next body of troops arrives. In my view of things they join with the troops who have not yet fainted or crossed the assault course. In your view, as I understand it, the parade ground is quiet because the troops are no longer there but are all busy at the assault course. The difference here is perhaps grounded in your comment: > The bit that is missing is tha fact that just before the exponential decay > started, the system was dealing happily with the full output of the CR tablet. You seem to be suggesting that the CR tablet delivers a peak (full) output at some point. My understanding, however, is that the CR tablet delivers a series of small parcels over the period of its life. It has been my suggestion that each of these deliveries would have a half life. Either way I think I will retire to the sergeants mess, order a long cold Emu Bitter and try to down it even as the earth shakes from another assault from the sinemet army. Its time for me at least to leave this parade ground. I look forward to your thoughts on how many make it over the assault course and at what rate. Dennis. ++++++++++++++++++++ Dennis Greene 47/10 [log in to unmask] ++++++++++++++++++++