I ASSUME from their letters that Michell Pickering, Christine Lambe and Steve Beddard, of Uncaged, are advocating experimenting on people. They attack the use of animals in research, but fail to suggest any alternative.

Animals are used when researchers need to find out what is happening in a whole living being. This may be in the study of what happens in the healthy body, what goes wrong in disease, or the development of potential treatments.

Of course, isolated cells and tissues are used to provide much useful information, but the living body is more complex than just the sum of its parts, so this is inevitably limited. So, the only real alternative to using animals in research is to experiment on people. I don't think society as a whole would view this as an ethical alternative.

No one is saying that animals provide perfect models for human diseases, but they are still the best we have. It is a fact that most major medical advances have depended crucially on animal studies - vaccines, antibiotics, insulin for diabetes and kidney transplants are just a few examples.

Most people would agree that medical research must use all appropriate and ethical means, including a small proportion of animal experiments, in the struggle to conquer diseases.

BARBARA DAVIES, Deputy Director, Research Defence Society, Great Marlborough Street, London W1.

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