Ten years after the death of Africanus Horton, a white woman who was eventually to be called ‘the Prophet of Africa to her own people’ landed in Sierra Leone. This illustrious label was given to Mary Kingsley by Horton's fellow African nationalist, Edward Blyden (Blyden 1901: 15). The mutual respect between Kingsley and Blyden grew out of their shared belief that white British culture should not be imposed on Africans. Although Kingsley was idealised by Blyden and many of her contemporaries in African affairs for this seemingly progressive cultural relativism, her recommendations were undergirded by some troubling and complex theories of racial science. Kingsley was quite happy to study African practices such as fetish and polygamy without an eye to reforming them, because she felt that the less African social structures were changed by whites, the more economically productive would be Britain's colonialism. She accorded black Africans greater disease resistance and thought they should be used accordingly for labour in the service of empire. Most fundamentally, she asserted that the Christian mission to improve African culture and religion was deluded because of her polygenist conviction that the races were irrevocably separate.

Kingsley's travels to Africa occurred during a key historical period when much had been discovered about the transmission of disease, but a few key links were still missing. As the 1893 guide Hygiene & Diseases in Warm Climates demonstrates, ‘It is only within recent years that the rôle of parasitic diseases in tropical pathology has been fully understood’ (Davidson 1893: v). Andrew Davidson describes Laveran's 1880 discovery of the malarial parasite, and even cites the parasite's life cycle in the blood, but still believes that this parasite is ‘generated only in connection with the soil’ (1893: 130). Until and even after Ronald Ross documented the transmission of malaria through mosquito bites in 1897, writers drew freely upon a mixture of infectious and environmental metaphors, and many continued to invoke the fatal tropical climate as the source of disease. In order to block widespread European settlement of Africa, which she believed would be both inimical to the welfare of African subjects and counterproductive to England's economic interests, Kingsley depicted the West African climate as irredeemably fatal for most whites.

Both Blyden and Kingsley were aware of the ‘fatal climate's’ rhetorical potential.