,” s aminate it. Breataminate it. Most of ter in our labs aminate it. e are all so get a reliably clean specimen you o excavate it in sterileconditions and do tests on it at te. It is trickiest t tocontaminate a specimen.”

    So sreated dubiously? I asked.

    harding nodded solemnly. “Very,” she said.

    If you and at once   is to be found a little beyond to t of Nairobi. Drive out of ty on toUganda, and t of startling glory h a hang glider’s view of boundless, pale green African plain.

    t Rift Valley, ectonic rupture t is setting Africa adrift from Asia. y milesout of Nairobi, along t site called Olorgesailie,  lake. In 1919, long after tnamed J. . Gregory ing ts ctered ones t  sites of Acool manufacture t Iantattersall old me about.

    Unexpectedly in tumn of 2002 I found myself a visitor to traordinary site. Iogeting some projects run by ty CAREInternational, but my s, knoerest in  volume, ed a visit to Olorgesailie into the schedule.

    After its discovery by Gregory, Olorgesailie lay undisturbed for over team of Louis and Mary Leakey began an excavation t isn’tcompleted yet.  te stretco ten acres or so, o 200,000 years ago. today tool beds are sered from t of tsbeneatin lean-tos and fenced off o discourage opportunisticscavenging by visitors, but otools are left just hem.

    Jillani Ngalli, a keen young man from tional Museum  as guide, told me t tz and obsidian rocks from ones from t a pair of mountains in tance, in opposite directions from