BEGINNING ON page 84 of this issue, scientists Alan M. Goldberg and Thomas Hartung describe recent advances in reducing, refining, and gradually replacing the use of animals in toxicology testing. Improvements in cell and tissue culture technologies, for example, allow a growing number of tests to be performed on human cells alone. Computer models, too, are becoming increasingly sophisticated, and many could one day become more accurate than trials in living animals as well as easier and less expensive.

The article's story of efforts to advance science and animal welfare simultaneously contrasts with the extremism and thuggery that mar the debate over lab animal treatment. Those scientists who act blindly unconcerned about the numbers of animals they use or the cruelty of experimental conditions have no idea how monstrous they appear to some of the public.

On the other hand, their opponents can go to insane lengths. Ask the family in Newchurch, England, who for 30 years bred sterile guinea pigs for research--and who abandoned the business last month. A seven-year campaign of harassment, threats and firebombings by animal-rights extremists, culminating in the disinterment and theft of a relative's body from a church graveyard, achieved its desired effect.

Since the late 1990s, Huntingdon Life Sciences--a company that conducts testing of substances on animals mandated by the Environmental Protection Agency and the Food and Drug Administration--has become a proving ground for increasingly aggressive tactics by animal-rights militants. At an October 2005 hearing, a Senate committee listened to testimony about vandalism, harassment and threats against Huntingdon employees and financial institutions providing services to the company. (Observers have speculated that such acts of intimidation may have something to do with the unexplained last-minute decision in September by the New York Stock Exchange to postpone adding Life Sciences Research, the parent company of Huntingdon, to its listings.) One antiexperimentation witness at the hearing asserted that any means necessary were justified to spare animals' lives; he has previously embraced the idea of assassination to that end.

Use of animals in testing and in biomedical research continues to be necessary in many instances and is ethically preferable to experimenting on humans or forgoing cures that could save human lives. But for the sake of people and animals alike, the development and acceptance of animal substitutes deserve enthusiastic support.

In some instances, substitutes are already deemed as good or better than animals, but regulatory agencies have yet to catch up. In both the European Union and the U.S., scientists and companies wanting to use the new alternative tests complain that regulatory standards for proving a drug or chemical to be safe for humans force the continued use of animals. Thus, animal-loving Americans might turn their political energies toward lobbying the EPA and the FDA to speed validation of new methods so that they can be more widely employed. And animal advocates who want to influence business could consider investing in the small biotechs and large pharmaceutical companies that are working to develop alternatives to animals in research.