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 more than floating tombs. They 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, experimented with how much water was needed for optimum numbers of slaves to survive on a diet of salted fish and beef jerky, 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.
When slaves couldn’t be kept alive, their autopsied bodies still provided useful information. Of course, as the writer Harriet Washington has demonstrated in her stunning Medical Apartheid, such experimentation continued long after slavery ended: in the 1940s, one doctor said that the “future of the Negro lies more in the research laboratory than in the schools.” As late as the 1960s, another researcher, reminiscing in a speech given at Tulane Medical School, said that it was “cheaper to use Niggers than cats because they were everywhere and cheap experimental animals.”
Medical knowledge slowly filtered out of the slave industry into broader communities, since slavers made no proprietary claims on the techniques or data that came from treating their slaves. For instance, an epidemic of blindness that broke out in 1819 on the French slaver Rôdeur, which had sailed from Bonny Island in the Niger Delta with about 72 slaves on board, helped eye doctors identify the causes, patterns, and symptoms of what is today known as trachoma.
The disease first appeared on the Rôdeur not long after it set sail, initially in the hold among the slaves and then on deck. In the end, it blinded all the voyagers except one member of the crew. According to a passenger’s account, sightless sailors worked under the direction of that single man “like machines” tied to the captain with a thick rope. “We were blind — stone blind, drifting like a wreck upon the ocean,” he recalled. Some of the sailors went mad and tried to drink themselves to death. Others retired to their hammocks, immobilized. Each “lived in a little dark world of his own, peopled by shadows and phantasms. We did not see the ship, nor the heavens, nor the sea, nor the faces of our comrades.”
But they could still hear the cries of the blinded slaves in the hold.
This went on for 10 days, through storms and calms, until the voyagers heard the sound of another ship. The Spanish slaver San León had drifted alongside the Rôdeur. But the entire crew and all the slaves of that ship, too, had been blinded. When the sailors of each vessel realized this “horrible coincidence,” they fell into a silence “like that of death.” Eventually, the San León drifted away and was never heard from again.