Question

Passage:
In the historiography of nineteenth-century epidemiology, the persistence of the miasma theory—which posited that diseases like cholera and yellow fever were caused by noxious emanations from decaying organic matter—is frequently framed as a mere scientific impediment, an archaic obstacle ultimately demolished by the advent of germ theory. However, this triumphalist narrative obscures the deeply intertwined political and economic motivations that sustained anti-contagionist paradigms, most notably articulated by the physician and political polemicist Charles Maclean. During the 1810s and 1820s, Maclean waged a relentless campaign against contagionism, arguing that the doctrine of person-to-person transmission was not only medically erroneous but also a deliberate instrument of state tyranny.

Central to Maclean’s thesis was the assertion that quarantine regulations, which were the primary public health manifestation of contagionist theory, were economically devastating and legally despotic. By restricting the movement of ships and merchants, quarantines obstructed the arteries of free trade—a burgeoning ideology in British political economy. Maclean contended that epidemic diseases were exclusively environmental phenomena, contingent upon local atmospheric and soil conditions rather than human contact. Consequently, he argued, quarantines were entirely useless in halting the spread of disease. To substantiate this, he pointed to the frequent outbreaks of yellow fever in port cities despite the strict enforcement of maritime quarantines, interpreting this as definitive proof that the pathogen was generated locally rather than imported.

Furthermore, Maclean’s anti-contagionism was intimately linked to his anti-imperialist and anti-monopoly political stances. He vigorously attacked the Levant Company, a British chartered monopoly that utilized the threat of plague and the necessity of quarantines to justify its exclusive control over Mediterranean trade. For Maclean, the medical establishment’s support of contagionism was merely a convenient intellectual veneer for protecting entrenched commercial monopolies and expanding unchecked executive power. While later sanitarians like Edwin Chadwick would also advocate for miasma theory primarily to champion domestic municipal engineering and sewage reform, Maclean’s earlier focus was almost entirely outward-looking, concerned with dismantling international trade barriers and the legal architecture of the quarantine system.

Ultimately, although Maclean’s medical conclusions regarding the etiology of infectious diseases were empirically incorrect, analyzing his arguments reveals that the mid-nineteenth-century medical establishment’s reluctance to embrace contagionism cannot be attributed solely to scientific conservatism. Rather, it was deeply enmeshed in a broader ideological conflict over the limits of state intervention in commerce and the ideological supremacy of free trade. By reducing the contagion debate to a binary of scientific progress versus ignorance, modern medical historians risk fundamentally misunderstanding the complex political economy that shaped nineteenth-century public health policy.

Based on the passage, which of the following claims about nineteenth-century epidemiological debates is explicitly supported?