Fall 2025

Russell and Burch’s landmark 1959 book, The Principles of Humane Experimental Technique, introduced the 3Rs of more humane animal research: replacement of animals as models, reduction in the number of animals used, and refinement of housing and handling methods to reduce animal stress and suffering. The authors considered “absolute replacement” to be the “absolute ideal.” Technological advances in “new approach methodologies” (NAMs), including nonliving organoids and organ chips, are increasingly making replacement feasible in some arenas. Yet absolute replacement still faces significant hurdles—technological, cultural, and otherwise.