I’ve felt the pull for years, to see what’s out there, how it differs from what I understand of the world. I’ve traveled distances to feed the pull. One destination, while still in the planning, thrilled me. Africa’s “Big Five” beckoned: lion, leopard, elephant, rhino, buffalo. I had my telephoto lens and a new bush hat—wide-brimmed, khaki-colored, with proper ventilation at the crown.  I pushed aside months of gripping headaches and growing fatigue, instead buying airfare, getting vaccinations. Nothing was going to sideline me. “You have a cavernous angioma.”  I looked at the doctor in his white lab coat with…