William Harvey announced the circulation of the blood in 1628, after nearly three decades of research on human cadavers and living and dead animals. In so doing, he opened a door to the experimental use of animals to find out about the human body. Experimenting on humans came shortly thereafter with blood transfusion experiments at the end of the seventeenth century.
Fast forward four centuries: it is now possible to order custom-made animals for particular experimental tasks, which include transplanting animal organs with human genes into humans. The popular press has reported that genetic manipulations make it possible to prevent heritable diseases, make bigger and better food animals, and bring back long-extinct animals. But as in Harvey’s time, few have talked about the ethical implications of such control over human and animal bodies and lives.
