A couple of days ago Jim Manzi posted a long and technical critique of my hypothesis that gasoline lead is strongly linked to the rise and fall of violent crime that we've experienced over the past half century. (Detailed in "Criminal Element" in our current issue.) It's the kind of critique that probably ought to be addressed by an expert, but unfortunately there don't seem to be any in my living room at the moment. Just me. So I'm going to respond myself, and hopefully others may respond in their own way later on.