The Science Behind the Deepest Itch: Poison Oak

One of my many childhood nervous habits was picking leaves. But not just picking leaves, picking leaves and stuffing them in my pockets, where I would crush them up into tiny balls of finger masticated plant matter. Like any nervous habit, I just did this, with no thinking or planning involved, because it would feel wrong if I didn't. Such are nervous habits. You can already see where this is going. One summer we were visiting my grandparents in the part of Kentucky that's technically in Illinoi...