Negro susceptibilities to diseases, perhaps even more than their immunities, were instrumental in branding blacks as an exotic breed in the eyes of physicians, planters, overseers, and others in intimate contact with them. Many of these susceptibilities first came fully to light on West Indian plantations where the climate, as in West Africa, was tropical, and a lively slave trade was able to supply fresh pathogens as well as fresh bodies for the cane, coffee, and tobacco fields.

If physicians in Africa were appalled by the loathsome “morbid afflictions of the skin” such as “lepra psoriasis,” “scabies,” and “frambesia” that blacks manifested, West Indian doctors were no less repulsed by them. Frambesia (yaws) blossomed on black bodies in the warm and humid islands becoming “one of the greatest evils to which negroes are subject.” Leprosy was another hideously disfiguring disease brought by the blacks from West Africa and another that physicians believed blacks were far more “subject thereto.” Called “cacabay” (coco bay) in some islands and the “joint evil” in others because the victim's toes and fingers tended to drop off at the site of the “evil,” the disease not infrequently deprived slaves of essential appendages which in turn deprived masters of their slaves' services.

Perhaps, however, the affliction that physicians and planters found most morbidly fascinating in the islands was the black propensity for consuming nonfoods, particularly earth. The habit of chewing small amounts of clay was not unusual in West Africa yesterday (nor is it today), but it frequently became transmuted in the slave quarters from a gentle habit to a raging compulsion.