Fourcroy, Antoine François De

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Fourcroy, Antoine François De

(b. Paris Frabnce, 15 June 1755; d. Paris, 16 December 1809)

chemistry, medicine.

A member of a noble family that had declined, Fourcroy was the son of Jean Michel de Fourcroy, an apothecary, and Jeanne Laugier. He left the Collège d’Harcourt in Paris at the age of fifteen, and after studying for a year under a writing master, became a clerk in the office of the chancellory. There he would have remained but for his good fortune in meeting F. Vicq d’Azyr, the anatomist, who persuaded his father to let Fourcroy study at the Paris Faculty of Medicine. Aided financially by members of the Société Royale de Médecine, of which Vicq d’Azyr was secretary, Fourcroy graduated as a doctor in 1780, but he did not practice medicine.

As a student he had shown great ability in chemistry and had lectured in the private laboratory of J. B. M. Bucquet, his teacher. Every winter from Bucquet’s death in 1780 until 1791 or 1792 Fourcroy gave a course of seventy lectures in his own laboratory which was published as Leçons élémentaires d’histoire naturelle et de chimie (Paris, 1782), and from 1782 to 1784 he also gave a summer course in materia medica. In all his lectures Fourcroy emphasized the relations between chemistry and natural history and their application to medicine. Fieldwork in natural history led him to publish Entomologia parisiensis (Paris, 1785), a detailed account of the insects of the Paris region, and about this time he also did some research on the anatomy of muscles; but he soon decided to concentrate on chemistry.

In 1783 Fourcroy received his first public appointment as chemistry professor at the École Royale Vétérinaire, at Alfort, near Paris, but this ended in 1787 when plans to expand the school were abandoned. His career did not suffer, for in 1784 he had succeeded P. J. Macquer in the important chair of chemistry at the Jardin du Roi. Here he lectured every summer to very large audiences and achieved fame by his brilliant exposition of a rapidly changing subject. From 1787 he added to his reputation by lecturing at the Lycée, a private educational institution on rue de Valois founded by J. F. Pilatre de Rozier.

The Société Royale de Médecine allowed Fourcroy to take part in its work while he was still a student and elected him to membership as soon as he graduated; he subsequently became one of its leading members, and his talent was further recognized in 1785 by his election to the Académie Royale des Sciences. Here he was in contact with A. L. Lavoisier, whose antiphlogistic theory he adopted in 1786, after several years of hesitation during which he had given his students a comparative account of the phlogistic and antiphlogistic theories. Most of the second edition of his Leçons élémentaires, retitled Élémens d’histoire naturelle et de chimie (Paris, 1786), was printed before 1786, and he announced his conversion in a specially written introduction. His Principes de chimie (Paris, 1787) was the first textbook written entirely according to the antiphlogstic theory.

In 1787 Fourcroy collaborated with Lavoisier, L. B. Guyton de Morveau, and C. L. Berthollet in the revision of chemical nomenclature, and he undertook the great task of completing the chemical section of the Encyclopédie méthodique, which Guyton had to abandon after completing volume I (Paris, 1789). Fourcroy was a teacher who always tried to arrange the fundamental principles of chemistry in a systematic order, and in his article “Axiomes” in the second volume of Encyclopédie méthodique (1792) he classified the chief facts of chemistry under twelve headings. When published separately as a little book entitled Philosophic chimique (Paris, 1792), this proved to be a very popular summary of antiphlogistic chemistry and was translated into eleven languages. Fourcroy also helped to advance the new chemistry as one of the editors of Annales de chimie, the journal founded in 1789 by Lavoisier and his colleagues; but he was more active as the editor of his own periodical, La médecine éclairée par les sciences physiques, which appeared fortnightly during 1791 and 1792 and was intended for medical practitioners wishing to keep up to date in all relevant branches of science.

While establishing his reputation as a professor and author, Fourcroy was also busy in the laboratory. One of the duties of the Société Royale de Médecine was to analyze mineral waters and assess their medicinal value, and in 1782 Fourcroy published a valuable account of the qualitative analysis of mineral waters by means of reagents, a method that was replacing the older analysis by evaporation to dryness. He considered that many of the reagents recommended in 1778 by T. O. Bergman were unnecessary and reduced the number from about twenty-five to eleven. Further, Bergman had not suggested any particular order for the reagents, but Fourcroy described a systematic analysis, using reagents that had the least effect on mineral waters before those that caused more complicated changes. A separate sample of the water was used for each test.

Fourcroy noticed that ammonia did not always completely precipitate magnesia from a mineral water containing it in solution. This led him in 1790 to investigate the reactions between salts of ammonia and of magnesia, and to the discovery of the crystalline double sulfates and double phosphates of the two bases. Bergman had recognized the existence of such salts in 1783, but few had been characterized.

Fourcroy’s interest in the application of chemistry to medicine led him to study various solids and fluids of the human and animal body in health and sickness. In 1785 he found that both human and animal muscle fiber contained a substance chemically similar to the fibrous matter in coagulated blood. This fibrous matter must have been derived from the animal’s food, which was inanimate; Fourcroy seems to have thought that it was converted into living muscle fiber by the agency of a vital force. C. W. Scheele and Berthollet had found nitrogen in animal matter, and in 1788 Fourcroy showed that there was a greater proportion of nitrogen in muscle fiber than in any other part of the body, and that the proportion of nitrogen contained in these fibers was the same for carnivorous and herbivorous animals. By 1789 he had found nitrogen in many vegetables, and it was therefore possible to account for its presence in herbivores without necessarily assuming that the animal absorbed it from the atmosphere.

Some parts of the body putrefied to form a white, waxy material resembling spermaceti, but in 1786 Fourcroy showed that it had a lower melting point than spermaceti and was more soluble in alcohol. Gallstones contained another similar substance (now known as cholesterol) which was only slightly soluble in alcohol and melted at a higher temperature than the others. This use of measurable physical properties to distinguish substances was very unusual before the nineteenth century.

Vegetable chemistry also interested Fourcroy, but to a lesser extent. His most important contribution was a detailed analysis of cinchona bark, which he extracted in a systematic manner with water, alcohol, alkalies, and acids. He did not isolate the active principle, but his analysis prepared the way for techniques that led to the extraction of cinchonine and quinine by P. J. Pelletier and J. B. Caventou in 1820.

About 1790 Fourcroy gave his first course in animal chemistry at the Lycée. He was assisted by N. L. Vauquelin, who collaborated in much of his research, but this joint work was done later, for Fourcroy’s scientific activities were interrupted by his entry into politics.

Like most French scientists, Fourcroy held liberal opinions and supported the moves that led to the French Revolution. He was one of about 400 representatives of the Third Estate in Paris who met in April and May 1789 to elect twenty deputies to the Estates General, but he took no further part in politics until 1792. In the meantime he served on local committees of health, education, and public welfare and continued his scientific work.

The government called on scientists to assist in solving the country’s economic difficulties. In 1790 Fourcroy successfully applied his chemical knowledge to the problem of extracting copper (needed for coinage and later for cannon manufacture and shipbuilding) from its alloy with tin, which, with the closing of many churches, was available in the form of bells. He heated the molten metal in air until the gain in weight showed that enough oxygen had been absorbed to oxidize the tin but not the copper. But at this stage some oxygen was combined with copper and some tin was uncombined, so, knowing that oxygen had a greater affinity for tin than for copper, he continued the heating in the absence of air. This caused all the oxygen to be transferred to the tin, leaving tin oxide and pure copper. The process gave a good yield of copper and was employed on a large scale for at least ten years.

The suspension of the monarchy and dissolution of the National Assembly on 10 August 1792 were followed by the election of a new National Convention and the declaration of the republic. Fourcroy became a member of the electoral assembly of Paris, the body that elected the deputies, but he had no ambition to enter politics actively and wished only to serve his country by continuing his scientific work. He stated this clearly on 10 September 1792, when he wrote to the government declining the position of régisseur des poudres et salpêtres (an administrative position concerned with gunpowder manufacture); but he failed in his attempt to remain a private citizen and on 21 September was elected fourth substitute deputy for Paris. He was called to take his seat in the Convention on 22 July 1793, after J. P. Marat’s assassination. Fourcroy now showed some enthusiasm for politics. He joined the Jacobin Club and became a member of the Committee of Public Instruction of the Convention.

After 10 August 1792 Fourcroy supported the expulsion from the Société Royale de Médecine and the Académie Royale des Sciences of émigrés and counterrevolutionaries, but none of the active members still resident in France were affected. He also supported the decision of the Convention on 8 August 1793 to suppress these bodies and all other academies that had enjoyed privileges under the monarchy. This did not affect certain independent societies, such as the Lycée des Arts (not to be confused with the Lycée), which was particularly concerned with the applications of science and included among its members Fourcroy, Lavoisier, and other academicians.

The suppression of the academies was not intended to be an attack on their members, and as a member of the Committee of Public Instruction, Fourcroy became partly responsible for organizing commissions of scientists to continue the most important work in progress. But in fact, the political and military problems of the day made it possible to set up only the commission that developed the metric system of weights and measures. Lavoisier was a member of this commission until after his arrest, with the other farmers-general of taxes, in November 1793. His trial and execution on 8 May 1794 came as a great shock to his fellow scientists, and there is evidence that Fourcroy made an unsuccessful last-minute appeal on his behalf to Robespierre and the other members of the Committee of Public Safety.

Fourcroy served on the government committee that founded the École Polytechnique in Paris (called the École Centrale des Travaux Publics when it opened in 1794) and new medical schools in Paris, Strasbourg, and Montpellier, which opened in 1795. These were urgently needed to train engineers and doctors for the army, but the École Polytechnique and the École de Médecine at Paris also became important research centers. Fourcroy was a professor at each until his death, and he also retained his chairs at the Lycée and the Jardin du Roi, which was reorganized in 1793 as the Muséum National d’Histoire Naturelle.

On 1 September 1794 Fourcroy was elected to the Committee of Public Safety, which had diminished powers after Robespierre’s downfall, and for several months he was deeply involved in the organization of munitions manufacture. From July to October 1795 he was again on the Committee of Public Instruction and helped to prepare an ambitious plan for national education which was to include écoles centrales for boys aged eleven to eighteen. Much science was to be taught in them, but few were successful, largely because of the shortage of science teachers. Fourcroy was also one of the planners of the Institut National des Sciences et des Arts, which replaced the old learned societies, and he became a member soon after it opened in 1795.

Fourcroy was elected to the Conseil des Anciens, one of the two assemblies that succeeded the Convention in 1795, but he did not serve on any of its committees and was not reelected in 1797. His return to private life lasted only two years, for on 25 December 1799 Napoleon appointed him to the council of state. By this time he had resumed his scientific work, and he was able to continue it while a councillor. He published a new treatise on chemistry, Systême des connaissances chimiques (Paris, 1801) and many research papers, but most of these were joint publications, generally with Vauquelin.

A useful contribution to inorganic chemistry was made by Fourcroy and Vauquelin in 1796, when they gave clear descriptions of the preparation and properties of sulfites and phosphites, including some new salts. In 1803, independently of H. V. Collet-Descotils, they examined the residue left when crude platinum dissolved in aqua regia and showed that it contained a new metal (which they named iridium), but they missed the second metal (osmium) that was discovered in 1804 by J. Smithson Tennant. In 1801 L. J. Thenard was Fourcroy’s collaborator in a masterly study of the oxides and salts of mercury, which definitely established the existence of two series of compounds containing mercury in different degrees of oxidation.

The action of sulfuric acid on vegetable substances was studied by Fourcroy and Vauquelin in 1797, and they showed that it did not always act as an oxidizing agent, as was generally believed, but sometimes decomposed vegetable matter by removing water from it, even though the water was not originally present as such but only as its elements. The sulfuric acid was unaltered chemically, and the reaction ceased when it became too dilute. In the particular case of alcohol, which yielded ether when treated with sulfuric acid, they considered that hydrogen and oxygen were removed from the alcohol, forming water, but the liberation of carbon that they observed led them to believe that the reaction was more complicated. Later, chemists recognized that the carbon came from impurities in the alcohol, but Fourcroy and Vauquelin had made an important contribution to the development of the theory of etherification.

Animal chemistry was still of great interest to Fourcroy, and with Vauquelin he examined many solids and fluids, including brains, mucus, nasal humor, and bile, and tried to explain their formation and function in chemical terms and to find medicaments that would restore them to their original state when altered by disease. Like most animal chemists of the day, they did not characterize any organic constituents of these animal substances, which, unlike vegetables, rarely yield crystalline and easily purifiable compounds.

Fourcroy and Vauquelin achieved more when they examined the inorganic constituents of animal matter. They found, for example, that the phosphates of lime and magnesia were present in the same proportions in milk as in bones, and that phosphorus in the soft roe of a fish was combined in such a way that it did not give the usual reactions of a phosphate.

Hundreds of concretions from various parts of human and animal bodies were analyzed by Fourcroy and Vauquelin. Most were urinary calculi which, independently of W. H. Wollaston, they classified according to chemical composition from 1798 onward. They confirmed the frequent presence of uric acid and phosphate of lime (discovered in calculi by Scheele and George Pearson respectively) and also found urate of ammonia, the double phosphate of magnesia and ammonia, and occasionally other compounds. Fourcroy hoped that the analysis of urinary calculi would lead to the discovery of solvents suitable for dissolving them by injection into the bladder, but this was not achieved.

In an attempt to find why urinary calculi were formed, Fourcroy and Vauquelin investigated urine, and in 1799 they gave the first satisfactory account of urea, which they named. (H. Boerhaave and H. M. Rouelle had previously observed a crystalline substance in evaporated urine but had not examined its properties.) Fourcroy and Vauquelin isolated it by recrystallization from alcohol and, in 1808, achieved a purer state by adding alkali to the crystalline nitrate that they had discovered. They found that urea yielded carbonic and acetic acids and ammonia when its aqueous solution was boiled; these were also the products of putrefaction, and they thought that calculi containing ammonia might be formed by the partial fermentation of urea in the bladder. Such speculations provided a valuable stimulus to the next generation of animal chemists.

As councillor of state, Fourcroy played a large part in drafting a new educational system, from primary schools to advanced colleges, and in 1802 Napoleon appointed him director-general of public instruction, with the great task of implementing the proposals. He achieved considerable success, and it was a disappointment when, in March 1808, he was not made grand master of the Imperial University, the corporation that was to control the entire system. It is probable that Napoleon wanted a grand master who was completely acceptable to the Roman Catholic Church, and he knew that Fourcroy was a freethinker. The post was given to Louis de Fontanes, a man of letters with orthodox religious views.

The title of count of the empire was conferred on Fourcroy in 1808, and he remained a councillor of state. During 1809 he was occupied in drafting new mining legislation, and Napoleon may have intended to appoint him director-general of mines. But Fourcroy’s health had begun to decline in 1808 and he died, aged fifty-four, before the mining law was passed.

Fourcroy was married to Anne Claude Bettinger in 1780; they had a son, an army officer who was killed in action in 1813, and a daughter. This marriage was dissolved in 1799, and in 1800 Fourcroy married Adelaide Flore Belleville, the widow of Charles de Wailly, a well-known architect. There were no children from the second marriage.


I. Original Works. An extensive bibliography of Fourcroy’s scientific writings is given by W. A. Smeaton (see below), pp. 211-252, with supplementary information in “Some Unrecorded Editions of Fourcroy’s Philosophie Chimique,” in Annals of Science, 23 (1967), 295-298.

II. Secondary Literature. There are two comprehensive accounts of Fourcroy’s life and work: W. A. Smeaton, Fourcroy, Chemist and Revolutionary (London, 1962); and Georges Kersaint, Antoine François de Fourcroy, sa vie et son oeuvre (Paris, 1966). Both books contain many references to manuscripts and printed sources.

W. A. Smeaton