Why would a person buy this medicine? What were they trying to treat? As a historical archaeologist who focuses on consumer medicine, I’m faced with this question more frequently than many historians of medicine. Archaeologists rarely have access to journals, letters, or other primary sources that mention specific products present in an archaeological assemblage—such as the one pictured below from my own research about the material culture of consumerism. Historians of business and economics who research drugstores or pharmacies, too, are frequently faced with daybooks that list the product being purchased and by whom, but without specific context or rationale for the purchase.

Despite differences in research methods and artifact access, archaeologists and historians frequently confront such uncertainties relating to medicine use and disease treatment. Such subjects are also often considered taboo and are therefore sometimes not as extensively discussed in the written record. These circumstances place a burden of speculation on the researcher that demands acknowledgement of personal bias and, importantly, the biases of information recorded in archives.

Many cultures and communities, for example, rely on oral traditions, which can sometimes limit a researcher’s ability to find archival sources that deal with specific folk traditions or beliefs. Historically, who has been allowed—or not been allowed—to write down knowledge can also influence possible interpretations. And the places researchers go to verify and fact check information can also have limitations. Books and manuscripts accessioned by archives or libraries and institutional collecting policies, themselves, often reflect the history and the values of the majority culture at the expense of other groups [1]. Current efforts to decolonize and diversify the archive are working to improve these issues, but such efforts are long processes.

As a small case study, this post will discuss how such biases and silences in archival sources may have led a popular 1984 article about Abraham Lincoln to arrive at incomplete and (unintentionally) biased conclusions about the Lincoln household’s use of pennyroyal, a common plant used in nineteenth-century pharmaceutical preparations, folk medicine, and herbals.

Despite the burden of speculation, archaeologists and historians can supplement traditional archival records by consulting alternate sources to better interpret material culture and craft richer and more complete interpretations of site studies and microhistories. Oral histories and cultural accounts recorded by folklorists, anthropologists, and local historians, for example, can be instrumental in helping researchers understand the sentiment of the public and discover the type of everyday “common knowledge” that rarely seems to get written down and deposited in archives.

Such accounts can also reveal information that has normally been tightly controlled by specific groups—particularly for information that surrounds taboo subjects such as sexual activity, menstruation, or supernatural beliefs and customs. Enslaved peoples’ oral histories collected by historians and folklorists through the Works Progress Administration during the Depression, for example, have proven invaluable for re-interpreting plant and patent medicine use from antebellum archaeology sites in the South [2]. By consulting information in these oral histories, researchers were able to improve their understanding of the material culture left behind by enslaved individuals and, later, sharecroppers.

This brings us to Abraham Lincoln and pennyroyal (Mentha Pulegium or European pennyroyal). In 1984, James T. Hickey, the curator of the Lincoln Collection at the Illinois State Library, published his article “Lincolniana: The Lincoln Account at the Corneau & Diller Drug Store, 1849-1861 a Springfield Tradition”[3]. Focusing on the daybooks from the Corneau and Diller Drug Store, the article analyzes the purchases made by the Lincoln family—with a particular focus on their medicinal applications—over the twelve years before they moved to Washington, DC. In the article, Hickey notes that the Lincoln family purchased the herb pennyroyal and suggests pennyroyal was probably used as a flea repellent, before quickly moving onto to discuss the other aliments that plagued the youngest Lincoln sons:

“Many items, of course, were purchased for the Lincoln children. Pennyroyal, purchased on April 14, 1852, was used to prevent flea and mosquito bites. Possibly, the Lincoln dog brought home a little problem for the boys.” (p. 62)

It is important here to emphasize that this pennyroyal might very well have been used as an insect repellent. This application of the herb is still commonly promoted in many published herbal guides today and was one of the earliest recorded uses for pennyroyal by Pliny the Elder in the first century CE [4] [5].

Oral histories and recorded folklore, however, indicate that consumers also used pennyroyal for a variety of other applications throughout history—and particularly in the nineteenth-century United States. A volume about folklore in neighboring Adams County, Illinois, by Harry Middleton Hyatt, for example, reports that, in addition to repelling insects, people used pennyroyal to treat colds, remove warts, and as an emmenagogue (an herb used to bring on menses) [6].  Oral histories and accounts from midwives also indicate that pennyroyal was occasionally used as an abortifacient when taken as a tea or powdered pill [7].  Though these other uses are mentioned less commonly today, modern purveyors of natural healing are reviving the use of pennyroyal to treat menstrual issues and to fight infections—while also warning about the potential toxic effects of the ingestion of pennyroyal oil [8].

So, why did Hickey not mention these potential alternative uses in his discussion of Lincoln’s purchases? He does not provide a citation for his assertion that pennyroyal was used as an insect repellant, but the answer to this question may bring us back to the biases of the archives and the written record.