Secret Cures of Slaves is a book about flux. Not so much the diarrhoea and dysentery which were an inevitable part of planation life, but the fluid nature of knowledge exchange in the Caribbean in the eighteenth century. The book presents a series of medical dramas involving the plants used to combat tropical pathogens. The effects of disease and attempted cures were played out on the bodies of the indigenous Caribbean inhabitants, the transported slaves and their descendants, white soldiers and sailors and, on occasion, members of the elite white population. Londa Schiebinger has written previously on the role of botany, materia medica and knowledge networks in the Atlantic world. She has investigated how knowledge did and did not pass between the free and the colonised and enslaved. Plants may have travelled across to the Old World, but understandings of their power to heal or work on the body could be held back, protecting the limited agency of the enslaved. Here Schiebinger combines these interests with concerns about human experimentation and the testing of cures and prophylactic interventions in the colonial Caribbean. Though parts of the book have appeared elsewhere as book chapters and journal papers, Secret Cures has a strong narrative to pull together what can (and cannot) be known of the flow of information within the Caribbean and across the Atlantic to Europe and West Africa, what she terms the ‘Atlantic World medical complex’ (p. 1).

In her analysis, the eighteenth-century Caribbean is turned into a laboratory for exploring how doctors independently, and at the behest of plantation owners, generated, researched and tested cures for diseases such as fevers, yaws and tetanus, and sought to prevent smallpox and yaws by inoculation. The division of the Caribbean between competing European powers who administered and paid their medics in differing ways provides a valuable source of contrast for the generation and circulation of knowledge. It reinforces how knowledge transfer could both follow patterns associated with language and national identity and move between colonial cultures when islands and plantations changed hands. This reinforces the sense of flux in a region made of large and small islands and the mainland colonies on the northern coast of South America. Schiebinger focuses on distinctions between Britain and France, but looks forward to future work involving other colonial powers in the region.

The example of the experimental testing of a European and a slave cure for yaws on the island of Grenada is particularly well worked. Schiebinger’s research throws into doubt the simple assumption that a slave cure was one generated in Africa and transferred along with the enslaved to the Caribbean. Yaws was perceived as a distinctly African affliction, so turning to ‘Negro Materia Medica’ (p. 9) made sense. This was particularly so in the eighteenth century when the now well-attested faith in local knowledge to combat tropical diseases was still respected. In the case of the Atlantic world medical complex, local knowledge was both African and Caribbean, as well as a blending of the two. Knowledge learned from Europeans was also added to this dynamic mix. Besides working as independent healers on single or multiple plantation complexes, plantation hospitals were also staffed by knowledgeable slaves who carried out the instructions of the formal plantation doctors. Such healers sometimes shared their knowledge, for a price. What comes to light in the yaws narrative is the importance of appreciating the identity and natural distribution of the plants used for a cure. If the chosen plants were indigenous to the Caribbean and not naturalised in Africa, the cure cannot have travelled across the Atlantic directly. However searching for similar plants with similar medicinal properties could still incorporate aspects of African medical knowledge. Knowledge could also have been shared between Amerindians of the Greater Antilles and slaves, or between Amerindians and early colonisers before they were overwhelmed by disease, killed or exiled to the Lesser Antilles. Knowledge could have passed to Europeans and back to slaves again. Schiebinger’s emphasis on the materiality of the plant cure is the key here: a point reinforced by negative attitudes to the spiritual realm of Obeah healing.

The materiality of slave bodies was also important, particularly the question of whether knowledge generated by tests on a passive black body could be applied elsewhere, including back in Europe on a white population. Schiebinger teases out the circumstances in which there was interchangeability across the races and genders and how this changes with time. She broadens the discussion of oppressed bodies and their use in the Caribbean to include the white soldiers and sailors who were stationed there. This illustrates her notion that there are conscious gradations of testing. Some tests involved patients who had much to gain from their enforced participation in the doctor’s work. In other cases ‘physicians took risks beyond what was reasonable to treat the individual patient’ (p. 11). She uses the example of smallpox and yaws inoculation to illustrate how doctors ‘took unusual liberties with human bodies’ (p. 11) but also points out that the doctor, though running the experiment, was not necessarily in control. Plantation owners had the final say over slave bodies, which represented capital invested in a commodity, and could call a halt as well as promote experimental medicine on slaves. Slaves’ ultimate designation as chattels left them disregarded by emerging ethical codes. She asks, perhaps a little optimistically, ‘might we have avoided the rampant exploitation of poor African Americans and other vulnerable populations in the centuries to come?’ (p. 90) had this not been the case? An excellent series of maps illustrates the direction, strength of flow and the blockages of the circulation of knowledge in the eighteenth-century Atlantic world. These visual aids reinforce the dynamic nature of the exchange probed in this fine study.