Sigaud De Lafond, Joseph-Aignan

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(b. Bourges, France, 5 January 1730; d, Bourges, 26 January 1810)

experimental physics, chemistry, medicine.

Sigaud de Lafond was the son of a clockmaker who was an artisan and man of letters. He began his education by studying for the priesthood with the Jesuits in Bourges, but later he decided to become a physician instead. He went to Paris and enrolled as a medical student at the school of Saint-Côme;.

While preparing for his medical degree, Sigaud attended the famous course of public lectures given by the Abbé Nollet, who aroused in him such a lively interest in experimental science that Sigaud became first a tutor in philosophy and mathematics and then a demonstrator in experimental science at the Collége Louis-le-Grand. In 1760 he succeeded the Abbé Nollet in his chair at Louis-le-Grand, where he taught courses in anatomy, physiology, and also those courses in experimental physics that had been taught by his famous predecessor.

In 1770 Sigaud became a professor of surgery at the school of Saint-Côme. In 1782 he returned to Bourges, where, after four years, he obtained a chair in physics at the local collège. The Revolution closed the collège, making his position temporarily difficult; but with the reorganization of public instruction under the National Convention and Directory, he became in 1795 professor of physics and chemistry at Bourges at the École Centrale, which replaced the old collège. With the creation of the lycées, Fourcroy, a former student of Sigaud’s and a member of the Council of State. appointed him proviseur (headmaster) of the school at Bourges. He resigned this position in 1808, two years before his death.

On 28 February 1796 Sigaud was elected a nonresident associate of the section of experimental physics of the National Institute. He belonged also to the academies of Montpellier, Florence, and St. Petersburg. In 1795 the Convention included him on a list of savants who were to receive a subsidy of 3,000 francs in gratitude for their services.

Sigaud was a prolific writer in the fields of experimental physics, chemistry, medicine, and (apparently as a consequence of his early Jesuit training) theology. Experimental science was a fashionable pursuit among the leisured classes in eighteenth-century France, and Sigaud was one of several illustrious popularizers who satisfied the intellectual appetites and curiosities of an ever-in-creasing number of amateurs of science. Popular interest tended toward the more spectacular examples of natural phenomean: and lectures accompanied by demonstrations, especially on electricity and on the newly discovered gases, always attracted large and enthusiastic crowds. As a follower of the Abbé Nollet, Sigaud was apparently quite successful in appealing to this group of virtuosi, and most of his publications were written for the enlightened layman rather than the professional researcher. As a result, his work was generally not profound, creative, or original. He avoided theoretical explanations and instead emphasized phenomenological aspects. There is something, too, in his writing of the vulgar catering to the “guût des merveilles”—the popular fascination with the strange, the unusual, the bizarre. He devoted an entire two-volume work to the “marvels of nature,” which went through at least two French editions and was translated into German. His positive contributions to science were in the area of experimental technique. He is sometimes attributed with the invention of the glass insulator and the circular glass plate (to replace the glass globe) in electrical machines. (. Wolf [see Bibliography] attributes the latter invention to Ingenhousz and Ramsden. and perhaps also to Planta.)

In the 1770’s Sigaud collaborated with Macquer in investigating the aeriform fluids or “airs,” newly discovered by Priestley. In 1776 they burned a quantity of the so-called “inflammable air” (hydrogen), and by holding a porcelain saucer over the flame they managed to collect a few drops of a colorless liquid that both researchers agreed was water. The experiment is often cited as an anticipation of some of the work later done by Cavendish, Lavoisier, and Monge on the synthesis of water, but neither Macquer nor Sigaud de Lafond fully recognized the significance of their observation.

In medicine, Sigaud achieved a certain notoriety for proposing, in a communication to the Royal Academy of Surgery, that section of the public symphysis could, in certain cases, be substituted for cesarean section. The Academy rejected the idea, but Sigaud was resolved to try it anyway. Specializing in midwifery, he established his medical practice in Paris, and finally in October 1777, he found an opportunity to put his new operation into practice. A pregnant woman, about forty years of age and deformed from rickets, came to him for help. She had already lost four babies, and the consensus of medical opinion was that she had no chance of bearing live children without a cesarean section. Sigaud, assisted by Alphonse Le Roy, performed instead a section of the pubic symphysis, and mother and child both survived the operation. Before the faculty of medicine in Paris. Sigaud read a memoir describing his procedure. The faculty ordered that the memoir be published in Latin and French and had a silver medal struck in honor of Sigaud and his assistant.


I. Original Works. Sigaud’s works include Le–ons de physique expérimentale, 2 vols. (Paris, 1767); Traité de l’électricité ... (Paris, 1771); Description et usage d’un cabinet de physique expérimentale, 2 vols. (Paris, 1775); Elémens de physique théorique et expérimentale .... 4 vols. (Paris, 1777); Essai sur différentes espèces d’air, qu’on désigne sous le nom d’air fixe ... (Paris, 1779); Dictionnaire des merveilles de la nature, 2 vols. (Paris, 1781); Dictionnaire de physique, 5 vols. (1781 – 1782); Précis historique et expérimental des phénomènes électriques ... (Paris, 1781); Physique générale, 5 vols. (Paris, 1788 – 1792); Examen de quelques principes erronés en électricité (Paris. 1796); and De l’électricité médicale (Paris, 1803).

II. Secondary Literature. On Sigaud and his work, see Biographie universelle, XLII (Paris, 1825), 316 – 318: H. Boyer, in Nouvelle biographie générale, XLIII (Paris, 1864), 966 – 967: Mechin-Desquins, Notice historique sur Sigaud de Lafond (Bourges, 1841); and A. Wolf, History of Science, Technology, and Philosophy in the Eighteenth Century, I (New York, 1961), 220. For details concerning Sigaud’s course of public demonstrations, see Jean Torlais, “La physique expérimentale,” in R. Taton, ed., Enseignement et diffusion des sciences en France au XVIIIé siècle (Paris, 1964), 619 – 645.

J. B. Gough