ABSTRACT
More than 30 years have elapsed since I prepared this chapter for the •rst edition.1 The book has been very successful, and the original chapter has been revised •ve times since then.2-5 Many things have changed since the •rst version. Toxicology has become a more mechanistic •eld. In this sixth edition, the general discussion has been extensively modi•ed. Some of the basic methods have been retained, because they are still utilized widely, without extensive changes, or they serve as prototypes for other assays. Several of the procedures have been changed in this sixth version, in order to re¦ect perceived needs in readers’ laboratories. In some cases, detailed protocols have been deleted because commercial manufacturers routinely supply detailed instructions; in those cases, some general guidance about the basis of the system will be provided. Readers are also referred to some details previously covered in earlier editions of the chapter and book.
