Feverish Bodies, Enlightened Minds: Science and the Yellow Fever Controversy in the Early American Republic by Thomas A. Apel (review)

"What is Enlightenment?" Kant famously asked in 1784. His answer: humankind's maturation into the adulthood of intellectual and moral self-determination. A decade later, on the other side of the Atlantic, Enlightenment ideals were on full display in a vituperative debate about the nature and causes of yellow fever, which had begun an epidemic reign of terror in Philadelphia, New York, and other U.S. port cities. In his short, incisive history of this debate, Thomas Apel argues that the intellectual environment of the early American republic shaped the understanding of yellow fever more powerfully than did the observed incidence of the disease on the ground. In doing so, he provides his own answer to Kant's question. Enlightenment, to Apel, was the appeal to "common sense," which he defines as the innate ability of ordinary people to discover the truth about the world, even without direct empirical observation.

In the flurry of polemical books and pamphlets published about yellow fever between 1793 and 1805, authors generally arrayed themselves in two camps: the contagionists, who believed that the disease was imported from the West Indies by ships and spread from person to person once it arrived, and the localists, who believed that epidemics arose from accumulations of filth and decaying organic matter under certain meteorological conditions. Apel rightly pays more attention to the localists, as there were more of them and they ended up either persuading, silencing, or outlasting nearly all of their opponents. (He repeatedly suggests that the contagionists were right all along, which they were not. Yellow fever was indeed imported, but it is not contagious.) Apel credits the localists' victory not to their superior understanding of the disease, but to their appeal to their readers' common sense and understanding of God's grand design.

This is intellectual history: readers will have to look elsewhere for stories of patients and treatments and relief efforts and panicked flight from stricken cities. However, those seeking a careful genealogy and unpacking of ideas—ideas about knowledge generation and ideas about the place of a new nation and of deadly epidemics in the great scheme of creation—will find much to appreciate here. Apel chronicles the emergence of the yellow fever debate out of a democratic culture dedicated to facts observable by anyone and independent of theory. Comprehensively detailed historical accounts of disease outbreaks served as the methodological cornerstones of most interventions. Apel also highlights an aspect of the debate previously underappreciated by historians: the fervor with which researchers sought the secrets of yellow fever in Lavoisier's new chemistry, minutely examining the composition of air and speculating exuberantly about the processes of decomposition and fermentation. He delves deeply into the religious association of filth with sin and of cleanliness with virtue, and into the paranoia about factionalism and conspiracy that pervaded the political culture of the early Republic, and the yellow fever debate in particular. As a guided tour of a bygone intellectual milieu in which life and death seemed at stake in the battle of ideas, the book is an impressive success.

Apel makes "common sense" do too much work in his interpretation of the localists' victory in the yellow fever debate. Its definition is slippery, both in this book and in the yellow fever texts. It often seems to have been used as an all-purpose claim of self-evident correctness. Other factors can explain the outcome just as well, or better. The localist perspective benefited from its flexibility, from the deep cultural resonances of filth and cleanliness that Apel highlights, and from the unpalatable political and economic implications of contagionism.

When localists denounced the idea of contagion, they frequently used words like "medieval" and "superstition." Belief in contagion was tightly linked to the history of the Black Death and subsequent centuries of...