Mohammed had a squirrelly look in his eyes, which together with his green-flecked teeth made me wonder whether to trust him. We had met that morning in Jijiga, Ethiopia, and he volunteered to show me — and then devour with me — the bleak town’s one real attraction: qat bushes. Here, near the Somali border, Mohammed cultivated qat and then shipped it all over the world for Horn-of-Africa expatriates who, like him, were utterly addicted to the numbing buzz you get when you chew its leaves for a few hours. They tasted about as bitter as you’d expect a shrub to taste. We were well into our fifth hour of chewing, and the bits of leaf gave his pearlies an emerald cast — the qat equivalent of the grotesque orange teeth one gets after scarfing a whole bag… More…