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How-To Manuals: Medicine, Botany, and Agriculture

Leonardo appreciated a good how-to manual for increasing his practical understanding of nature and the human body. Here he was a pragmatic rather than a critical or imaginative reader. While Renaissance publishers did not invent this genre of publication, they ensured the longevity and circulation of these works by putting them into print.

Renaissance readers interested in medicine knew that Rhazes (al-Rāzī) was one of the great medieval Islamic authorities. His tenth-century compendium synthesized vast amounts of medical learning about diet, drugs, and surgery in an easy-to-consult format. Copyists and printers, realizing that this book could easily be excerpted, transformed individual chapters into affordable medical pamphlets full of useful medical wisdom. This was probably how Leonardo read Rhazes. By definition, a practical manual did not have to be read in its entirety, since it was a book to consult on particular topics.

Herbals and agricultural treatises represent two distinct approaches to communicating practical knowledge of nature. If Leonardo wanted to know more about an individual plant, he consulted an herbal. Herbals described plants and their medicinal uses. They paid attention to details important to proper identification, including experiments in depicting plants, despite Pliny’s admonition that images often confused and conflated details best sorted out with verbal description. An agricultural manual focused instead on the cultivation of nature, discussing everything from crop rotation, viticulture, animal husbandry, and plant grafting, though Piero de’ Crescenzi also borrowed material from Albertus Magnus’s botanical studies. Reading across these manuals gave Leonardo a more complete portrait of the natural world, enriching his sense of naturalism.

[Paula Findlen]

Arnald of Villanova, 1240–1311, attributed author

Incipit tractatus de virtutibus herbarum

Venice: Alessandro Bindoni, 1520

Lane Medical Library V81H .A84 1520

Attributed to the medieval Spanish physician Arnald of Villanova, the popular De virtutibus herbarum belongs to a world of manuscript and printed herbals that increasingly featured images of plants alongside textual descriptions. Villanova was in the forefront of alchemy and medical education through his observations and experiences as a religious reformer and physician. The herbal emphasizes the important intersection between visual and verbal communication through its detailed drawings and descriptions. The Renaissance owner of this copy has chosen to color some of the plants in red, possibly in order to differentiate parts and species. Alessandro Bindoni’s Scales of Justice printer’s device adorns the title page, and the colophon attributes the printing of the volume to him.

Herbals played a vital role during the Renaissance for understanding nature and its potential remedies. Medieval Galenic medicine, which Leonardo challenged and studied, emphasized the hybridity of natural history and medicine. Leonardo’s fascination with nature and science suggests the importance of an herbal in his library collection. Through the use of an herbal, he was able to understand the different uses and features of plants and their visual representation and verbal description. Leonardo’s study of nature informed his extremely detailed backgrounds and depth in his paintings. His study of history, medicine, and nature allowed for revolutionary depictions of perspective, proportion, and anatomy, but if he wanted to know more about a single plant, he needed to read an herbal.

[Gracia Leydon Mahoney]

Piero de’ Crescenzi, ca. 1233–1320

De agricultura vulgare

Venice: Alessandro Bindoni, 1519

Rare Book Collection KB1519 C7

Piero de’ Crescenzi’s De agricultura vulgare is one of the most famous texts on the agricultural and natural world of the late Middle Ages and the Renaissance. The book, believed to have been completed sometime between 1304 and 1309, is based on Crescenzi’s experiences as a landowner in addition to classical and medieval sources. The text is divided into twelve parts, ranging from detailed mock-ups of an ideal irrigation system in a city to advice on cultivating vineyards and how to hunt and fish properly in various conditions. The work was dedicated to King Charles II of Naples, but was a popular text coveted by many more modest landowning families.

We can deduce the impact of Crescenzi’s text from the way in which readers of this copy interacted with the text in the margins, and the many translations from the Latin original. Its influence was felt in many Italian cities, including Leonardo’s Florence and Milan, as well as abroad. De agricultura vulgare became a guide for Mediterranean rituals of cultivation, addressing human interaction with the natural world. The text was referenced often throughout the early modern period, especially in Bologna, where its instructions on how to create a model farm made Bolognese agriculture famous. Leonardo owned a copy of Crescenzi’s book by the mid-1490s. He most likely took an interest in Crescenzi’s description of the construction of irrigation systems and granaries. This research informed his drawings of an ideal city plan for Milan.

[Mikey Diekroeger]

Abū Bakr Muhammad Ibn Zakariyya al-Rāzī (Rhazes), 865–925

Liber ad Almansorem

Venice: Boneto Locatelli, 1497

Lane Medical Library H128.9H .C76 1497

This book contains a Latin translation of one of the most famous medieval Arabic medical treatises, the Kitāb al-Manūrī, a ten-chapter textbook on general medicine dedicated in 903 to Abu Salih al-Mansur, the governor of Rayy (near Tehran in modern Iran). Known as the Liber ad Almansorem, it became one of the most widely read medieval medical manuals during the Renaissance. The ninth chapter of the book, which provided a detailed examination of medical pathologies of the body, became quite famous and circulated widely by itself as the Liber nonus. This printed edition also includes twenty widely read medical tracts of the time from authors such as Hippocrates.

The author, al-Rāzī, or Rhazes in Latin, was a famed medieval Islamic physician known for directing an important hospital in Baghdad during the Abbasid Caliphate and for his influence as a medical encyclopedist. As an author, he added his own considered judgment and medical experience as commentary, unafraid to critique figures such as Galen on specific teachings if his own observations presented different information. Such an approach resonated deeply with Leonardo, who believed in the necessity of experiencing the natural world and using it to inform his studies.

Included in Leonardo’s list of titles, this book is a prominent example of the medical texts he engaged with in his study of medicine and how it shapes the human body. The extensive marginalia provide insight into how he might have physically engaged with this book as a Renaissance reader.

[Steven Doan]