[…. Consider, for example, the way the advancement of medical knowledge was paid for with the lives of slaves.
The death rate on the trans-Atlantic voyage to the New World was staggeringly high. Slave ships, however, were floating laboratories, offering researchers a chance to examine the course of diseases in fairly controlled, quarantined environments. Doctors and medical researchers could take advantage of high mortality rates to identify a bewildering number of symptoms, classify them into diseases, and hypothesize about their causes.
Corps of doctors tended to slave ports up and down the Atlantic seaboard. Some of them were committed to relieving suffering; others were simply looking for ways to make the slave system more profitable. In either case, they identified types of fevers, learned how to decrease mortality and increase fertility, and identified the best ratio of caloric intake to labor hours. Priceless epidemiological information on a range of diseases — malaria, smallpox, yellow fever, dysentery, typhoid, cholera, and so on — was gleaned from the bodies of the dying and the dead…]