The test, used to evaluate whether products will cause dermatitis, is the first to pass muster under a new federal program to help evaluate alternatives to current animal tests, called the Interagency Coordinating Committee on the Validation of Alternative Methods (Science, 4 April 1997, p. 41). The committee oversees peer review of proposed tests and forwards recommendations to more than a dozen federal agencies, which then decide whether to adopt a test.

In the standard skin test, a substance is painted on a guinea pig, which is then injected with a chemical that aggravates any skin reaction. In the new test, developed by scientists from three companies, a substance is applied to a mouse's ear. The animal is euthanized a few days later, and its lymph node tissue is examined for signs of an immune reaction. This test "spares the animal any pain and suffering associated with allergic contact dermatitis," says Martin Stephens of the Humane Society of the United States.

The new test can't replace the old one in all cases, such as testing metal salts, says committee co-chair William Stokes. However, he says, it may yield better data, because scientists know more about the mouse immune system than about that of guinea pigs.