The central question when examining the career of Mary Mallon, cook, is always, ‘Why did she go on cooking when she had every reason to believe she was spreading a possibly fatal disease?’ Many of you who’ve worked in greasy spoons, coffee shops, cafeterias, failing, not-very-good restaurants, institutional food services, know the answer already. I won’t blame you if you don’t care to admit it. But you know what the ‘three-second rule’ is. Don’t you?