We have the second part of an interview with renowned food writer Harold McGee (the first part was broadcast on Dec. 23). McGee's book, On Food and Cooking: The Science and Lore of the Kitchen, has been revised and updated. The book is an exposition of food and cooking techniques, technology and history. He diagrams the stages of making mayonnaise under a microscope, explains why peppers are hot, and why seafood gets mushy if you cook it improperly. McGee is an authority on the chemistry of cooking.