Immunities of Empire: Race, Disease, and the New Tropical Medicine, 1900-1920

In 1900, Nathaniel Southgate Shaler, the dean of Harvard’s Lawrence ScientiÞc School, proposed that the “troops which are required for Federal service in tropical lands might well be recruited from the negroes”; with their families, these soldiers would soon “become permanently and contentedly established in Luzon and elsewhere in the colonies.” ¹ Shaler was convinced that such “children of the tropics” would “make excellent soldiers—at least as infantry men”—because the African-American constitution was preadapted to the tropical disease environment. ² But in the Philippines, Shaler’s distinguished advice was already redundant: during the previous two years, the United States had been using African-American and Filipino scouts to suppress the resistance to its occupation of the archipelago. To Capt. R. L. Bullard, one of the “white men of good standing” who commanded the “30th Alabama Volunteer Infantry (Negroes),” it had long been plain that “negro volunteers” were less liable to succumb to the regional ailments than white soldiers; indeed, the differences in health and labor power between the two groups were “so great that they almost require the naturalist and do require the military commander to treat the negro as a different species.” ³ But while black troops “could accomplish the most amazing amount of work” in such trying circumstances, they unfortunately showed a tendency to “go in parties, they herd,” and “in the lonely duty of the sentinel this herding peculiarity becomes a positive fault.” ⁴ Filipino scouts proved more abundant and somewhat more independent, though similarly resistant to the tropical diseases and climate of their ancestral realm. Capt. Charles D. Rhodes observed that local troops were “able to drink all kinds of water with impunity, and the common intestinal disorders are unknown”; they were susceptible perhaps only to “calentura or break-bone fever.” ⁵ As the Filipino soldier “stands in the rice-Þelds, knee-deep in mud and water, during the working hours of day after day, one almost believes that years of exposure have made him amphibious. The factor of sickness among soldiers made of such material will not cause the surgeons much uneasiness.” ⁶ And indeed, for the Þrst few years of the American occupation, it did not.

Assumptions of racial immunity to disease pervade nineteenth-century medical and social theory. For colonial physicians in particular, racial endowment provided a potent, if somewhat inchoate, means of understanding observed differences in disease susceptibility. It was a truism, in the tropics as elsewhere, that contact with the exciting cause of disease—whatever its nature—did not always produce the same pattern of illness among individuals. Disease manifestation seemed to depend on the condition of the body at the time, which was the sum total of hereditary endowment, life history, and environmental inþuence. Whether this aggregate was called constitution, immunity, or “vital machine,” ⁷ the importance of predisposition seemed, for most of the century, beyond doubt. And in colonial circumstances, racial difference was undoubtedly the most prominent of all the possible inþuences on a population’s immunity or liability to disease. The principle that a race was best Þtted to resist the diseases of its ancestral realm—and, as a corollary, was especially susceptible to ailments encountered in a foreign land—was a remarkably resilient element in the general understanding of disease susceptibility. Such assumptions form a large part of the texture of contemporary hereditarian thought. ⁸ An enormous amount of colonial epidemiological research and diverse clinical experience could be built into this framework of meaning.

The supposition that manifold racial difference would somehow shape disease expression was itself relatively immune to etiological and therapeutic change. To an extent, it did not matter much whether the cause of the ailment was miasma or microbe. Even during a period when such speculation about the seed of disease regularly obscured the old, surer, pieties of the soil, the standard assumptions of predisposition were never entirely displaced. ⁹ But if this interest in patterns of natural immunity was surprisingly long-lasting, the form it assumed was never immutable. Although “race” remained an organizing principle...