by Elio — Now that news of the ar­senic-eat­ing bac­te­ria has sat­u­rated cy­ber­space, the air­waves, and even old-fash­ioned newsprint, we step back to raise a larger ques­tion: Why have so few el­e­ments from the pe­ri­odic ta­ble made it into liv­ing things? You sel­dom hear about any­thing past the first few rows in the ta­ble.