While Darwin effectively undermined the idea of any kind of genesis with the publication of On the Origin of Species in 1859, the damage to the medical reputation of black people generally, and black soldiers in particular, had been done. Attention in the 1860s and 1870s turned to the performance of the West India Regiments in West Africa in campaigns against the Asante people. Military surgeons, steeped in the now-established medical orthodoxy of black vulnerability to a variety of diseases (particularly lung complaints), constantly grumbled that the West India Regiments were no longer medically fit for purpose. After the 1850s most West India Regiment soldiers were born in the West Indies, rather than in Africa, reducing the rates of acquired immunity to yellow fever. And while the men of the West India Regiments had never been immune to all forms of malaria, surgeons only now began to notice how many of them succumbed to tropical fevers. By the 1870s there was a growing belief that white soldiers should be preferred for campaigns in West Africa, as West India Regiment troops were not thought physically capable of withstanding the climate. Blackness had been transformed from conferring a medical advantage to being a medical liability.