VIREY Julien Joseph Éphémérides de la vie humaine, ou recherches sur la révolution journalière et la périodicité de ses phénomènes dans la santé et les maladies.

Reinberg (A.E.) and Lewy (H.), ‘Julien Joseph Virey and the Birth of Chronobiology’, *Rythmes* (Newsletter of the Francophone Society of Chronobiology, Faculty of Science and Technology, 23 rue du Dr Michelon, 42023 Saint-Étienne cedex), 2001, vol. 33, no. 1, pp. 3–9.

First edition, inscribed to “A Monsieur le docteur Petitot, médecin, de la part de son confrère, J.J. Virey, d.m.p.”

This is almost certainly P. Petitot, a Parisian doctor and author of a thesis defended at the Paris Faculty of Medicine in 1809, Essai sur le régime qui convient aux différens tempéramens, considéré en l’état de santé. This thematic similarity — diet, temperaments and hygiene — sheds light on Virey’s choice, as his research here focuses on physiological rhythms and their influence on health and illness. Petitot belonged to the same Parisian medical circle as Virey and was among the subscribers to the Dictionnaire des sciences médicales, a vast editorial project to which Virey was contributing. Virey’s use of the phrase ‘his colleague’ thus attests to a professional relationship between the two men and situates this copy within the Parisian medical network of which the author was a part.

A unique doctoral thesis in which the author seeks to establish a relationship between mortality from disease and the 24-hour cycle, otherwise known as the Nycthemeron.This pioneering work is considered the seminal text of chronobiology and chronotherapy.

Virey concludes his thesis with a statistical table of mortality compiled between May 1807 and May 1808. Analysis of this data leads him to identify periods when mortality is lower and others when it is higher: “The times when people die the least are from 10 pm to 3 am, or the hours of the first sleep, and also those from 8 am to 10 am, and from midday to 1 pm. Mealtimes at 10 am and 4 pm in hospitals are fairly healthy; the hour following is less so, no doubt due to the effects of difficult digestion”.

Presented in Paris in 1814, the author argues in his thesis that biological rhythms have a significant influence on patients’ state of health and on the likelihood of the time of death. He is the founder of chronobiology and its foremost exponent.

A fine copy with full margins, with a dedication to a colleague.