It should soon be easier to tell without killing animals

THE number of chemicals that might come into contact with a human being is staggering. The European Chemical Agency (ECHA) recognises over 130,000 molecules. Its American counterpart recognises 85,000. Testing all of these for toxicity is well-nigh impossible. Animal testing, in particular, is controversial, slow, costly and often cruel. Nor is it reliable. Its results are often irreproducible. Things would be better if there were some way to predict the likely toxicity of a substance before ani...