Epidemiorum et ephemeridum libri duo, Studio & operâ M. Iacobi Thevart Medici Parisiensis, digesti, Scholiis aliquot illustrati, & in lucem primùm editi

First posthumous edition of Guillaume de Baillou's Epidemiorum et ephemeridum libri duo, edited and annotated by Jacques Thévart, who dedicated the work to Charles Bouvard, chief physician to Louis XIII. Preceded by an address to the reader by Baillou. Title printed in red and black, with the printer's device. Collation: title, 9 unnumbered leaves, 273 pp., 9 unnumbered leaves (Krivatsy 588; Garrison-Morton 1673, 5047 and 5085).

Bound with three further treatises by Baillou, likewise published by Jacques Thévart through Quesnel, all in their first editions.

The first, Definitionum medicarum liber, deals with medical definitions and the interpretation of difficult passages in Hippocrates and Galen. Originally published in 1639, it is here furnished with a cancel title-page dated 1640 (title printed in red and black, 9 unnumbered leaves, 108 pp., 4 unnumbered leaves; Krivatsy 587; Garrison-Morton 6796). Through a binder's error, its title-page and preliminary leaves were placed immediately after the preliminaries of the Epidemiorum, while the main text follows the 273 pages of the first work.

The second, Commentarius in libellum Theophrasti De vertigine, presents the Greek and Latin texts of Theophrastus's treatise on vertigo, together with Baillou's commentary (title, 1 unnumbered dedication leaf, 41 pp., 1 unnumbered leaf; Krivatsy 582).

The third, De convulsionibus libellus, concerns convulsive disorders (title, 7 unnumbered leaves, 51 pp., 2 unnumbered leaves; Krivatsy 585).

Krivatsy records a volume comprising the same four works and suggests that they may have been issued together. Their presence in the present copy may therefore reflect an arrangement originally offered by the publisher, rather than a collection subsequently assembled by an individual owner.

Contemporary stiff ivory vellum, spine with four raised bands and the author's name lettered in black ink, blind-tooled rolls at the head and foot of the spine, gilt fillets outlining the bands and forming borders on the covers, edges sprinkled red. Damage to the fourth raised band, a few small losses of vellum to the covers, and losses to the corners of the first and last blank endpapers.

Guillaume de Baillou (1538–1616), a pupil of Jean Fernel and Dean of the Paris Faculty of Medicine in 1580, was among the foremost French clinicians of the Renaissance. In 1601 Henri IV offered him the position of chief physician to the Dauphin, the future Louis XIII, which he declined. Although a small number of his writings appeared during his lifetime, the greater part of his work remained unpublished at his death. From 1635 onwards, Jacques Thévart undertook the posthumous publication of these manuscripts, bringing several decades of clinical observation and medical reflection into print.

The Epidemiorum et ephemeridum libri duo occupies a particularly significant place within this undertaking. It records the diseases observed in Paris between 1570 and 1579, relating their occurrence to the seasons, changes in the weather and the circumstances in which they arose. Following the method of Hippocrates' Epidemics, Baillou studied disease not merely through the symptoms presented by individual patients, but also through its distribution across a population and its relationship with atmospheric conditions. His concern with the so-called 'epidemic constitutions', subsequently developed by Thomas Sydenham in the following century, established his reputation as one of the principal forerunners of modern epidemiology.

Among the cases recorded are an epidemic of diphtheria in Paris in 1576 and an account of tussis quintana, now identified as whooping cough. Garrison-Morton assigns the work three separate entries in recognition of its contribution to the doctrine of epidemic constitutions and its descriptions of these two diseases. Bariéty and Coury likewise rank Baillou among the leading authorities on infectious disease in his period, crediting him with the first recognition of tussis quintana as a distinct clinical condition, subsequently known in French as coqueluche.

The importance of these observations lies equally in the method employed. Rather than considering symptoms in isolation, Baillou followed diseases through their development, recurrence and seasonal variations; drawing on his Parisian medical practice, he thus constructed a history of epidemics attentive to their evolution over time. Long regarded as a landmark in observational medicine, the two books received a critical edition with French translation by Joël Coste and Hélène Maggiori, published by Les Belles Lettres in 2021.

Thévart's dedication to Charles Bouvard places the publication within the medical establishment of the court of Louis XIII. Chief physician to the king since 1628, Bouvard had also been appointed superintendent of the Jardin royal des plantes médicinales in 1635, an institution which opened to the public in 1640. The dedication to the head of this new establishment, devoted to the teaching and study of medicinal plants, thus accompanies the renewed circulation of a body of work rooted in the clinical tradition of the Paris Faculty of Medicine.

A collection of four posthumous first editions in a single contemporary vellum binding, its composition paralleled by the copy described by Krivatsy. The Epidemiorum, preserving Baillou's observations of diseases in sixteenth-century Paris and one of the earliest clinical accounts of whooping cough, is accompanied by three further treatises edited by Thévart; their association, extending to the 1640 cancel title-page of the Definitionum medicarum, preserves material evidence of this posthumous publishing enterprise.