PECQUET, JEAN

(b. Dieppe, France, 9 May 1622; d. Paris, France, February 1674)

anatomy.

Pecquet spent his youth in Normandy, first in Dieppe and then in Rouen, where he met Blaise Pascal. In 1642 he went to Paris, where he was a member of the various scientific circles that preceded the Academie des Sciences. He joined the entourage of the Fouquet brothers, Francois, bishop of Agde, and Nicolas, superintendent of finance. Pecquet enrolled at the Paris Faculty of Medicine around 1646, at the age of twenty-four. Finding the atmosphere unfavorable, he matricualted at Montpellier on 15 July 1651, received his licence on 16 February 1652, and defended his doctoral thesis on 23 March 1652.

Pecquet subsequently returned to Paries, where he had both worldly and scientific careers. He was physician to Nicolas Fouquet, as well as to the Marquise de Sévigné, her daughter, and her grandchildren; his name occasionally appears in the marquise’s correspondence. Pecquet was also friendly with the Paris scientists Jacques Mentel, Louis Gayant, Adrien Auzout, and Claude Perrault. He probably knew Steno from the time of the latter’s visit to Paris (1662–1665), as well as other, less notable foreign physician of Bern.

The quantity of Pecquet’s scientific production was slight. He participated in experiments on the transfusion of blood performed in 1666–1667 at the Académie des Sciences, as did his friends Gayant (provost of the communauté of the surgeons of Paris and consulting surgeon to the royal army) and Perrault.

The Mémoires de l’ Académie royale des sciences for 1666 to 1669 (10 [Paris, 1730], 476–477) mentions a note on live parasties. Pecquet also debated the question of the agent to viston with Mariotte (1669), who contended that it was in the choroid coat; Pecquet believed the retina to be the sensory membrane. Pecquet’s only important accomplishment was the discovery of the chyle reservoir, which he called the receptaculum chyli not cisterna, a word introduced into anatomical nomenclature by his friend Thomas Barholin.

To understand the genesis of Pecquet’s investigations, it is important to remember that when he began them, the great discovery dividing and preoccupying physicians was that of the circulation of the blood. Harvey had announced it in 1628 and returned to it in 1649 in his two letters to Jean Riolan, dean of the Paris Faculty of Medicine. Rejected by the Paris medical officials, Harvey’s discovery was taught at the Jardin du Roi and furnished dissenting physicians with subjects for study, such as the circulation of various body fluids, as well as methodology, anatomia animata, the ancestor of experimental physiology. The experimenting physician, who actively examined nature instead of passively contemplating it, was Pecquet’s ideal.

Pecquet was probably introduced to the study of the lymphatic system by Mentel, a Harveian physician who had received his doctorate at Paris in 1632. Tradition relates that Mentel had observed human lymphatics around 1629, but it was Aselli’s discovery in 1622 of the chyliferous vessels in the dog that drew the attention of researchers to the “white vessels” Aselli’s discovery had also propagated the erroneous idea—accepted by Vesling (1647), among others—that the chyliferous vessels terminate in the liver after traversing the pancreas. Aselli’s “panceras” included both the true pancreas and the groups of ganglia situated behind it in the mesentery.

Harvey believed that the resorpition of the chyle occurred in the mesenteric veins and liver was the site of hematopoiesis. His chief opponent, Jean Riolan, did not admit the existence of the “white vessels,” even though Falloppio had probably seen the lymphatics of the liver and Eustachi had observed the thoracic duct of the horse (vena alba thoracis) in 1564. In 1642, the year of Pecquet’s arrival in Paris, Johann Georg Wirsung discovered the duct that bears his name; but yet instead of indentifying it with the excretory canal of the pancreas, he considered it to be a chyliferous vessel, emerging from the intestine and ending in the pancreas.

It was in these circumstances that Pecquet, while still a student, defied the reigning conceptions and engaged not in the “mute and frozen science” of cadaver anatomy, but in anatomia animata on dogs, cattle, pigs, and sheep. Using a dog that was digesting, he showed the following:

1. If the heart has been resected, pressure on the mesenteric root causes the chyle to spurt into the superior vena cava.

2. The chyle is directed toward the subclavian veins by two paravertebral canals that swell when their distal extremities are ligatured.

3. The origin of the ascending chyliferous ducts is situated in a prevertebral and subdiapharagmatic ampulla—“this sought-after sanctuary of the chyle, this reservoir sough with so much difficulty.”

4. The posterior part of Aselli’s pancreas is composed of lymphatic ganglia.

5. No mesenteric chyliferous vessel goes to the liver (a fact confirmed by Glisson in 1654), and the inferior vena cava, incised above the liver, reveals no trace of chyle.

The human thoracic duct was rediscovered by Thomas Bartholin, Rudbeck, and Gayant. With Perrault and Gayant, Pecquet eventually observed the communications of the human thoracic duct with the lumbar veins.

Pecquet’s discovery was received with great interest and provoked sharp debate, particularly with Riolan. It was warmly welcomed by Bartholin, who distinguished the chylous vessels from the other “white vessels,” which he called lymphatics, and by Rudbeck. The latter saw the lymphatic system as a new type of vascular system, long unrecognized because it can be made visible only by special preparations. Neverthe-less, the significance of the lymphatic system was still far from clear. Lympho-nerual anastomoses were desribed in terms of Cartesian “nerve tubes.” Wharton and Glisson thought that the glands received juices excreted by the nerves and that glands received juices excreted by the nerves and that they eliminated them through the lymphatics. Pecquet, like Bartholin, belisved that communications existed between the cisterna chyli and the urinary tracts; these structures would short-circuit the renal tubule system and would explain the rapid filling of the bladder after a copious intake of liquid.

Pecquet’s friend Perrault likened the thoracic duct to a glandular canal, thus showing that he still believed in humors carried by special vessels and not in “juices” (sucs) synthesized by the glands from the blood.

BIBLIOGRAPHY

I. Original Works. Pecquet’s major writing, the Experimenta nova anatomica, went through several eds. and versions: Experimenta nova anatomica, quibus incognitum hactenus chyli receptaculum et ab eo per thoracem in ramos usque subclavios vasa lactea deteguntur. . . (Paris, 1651); a copy of this ed., with illustrations (Harderwijk, n. d.) Experimenta nova academica. . . Huic secundae editioni. . . accessit de thoracicis lacteis dissertatio in quq Jo. Riolani responsio ad eadem experimenta nova anatomica, reprrtatur . . . (Paris, 1654); Experinrenta nova anatomica, quibus incognitum hactenus chyli receptaculum et ab eo, per thoracem, in ramos usque subclavios vasa lactea deteguntur. . . . Accedunt clarissimorum virorum epistolae tres ad auctorem, in J. A. Munierus, De venis tam lacteis thoracicis quam lymphaticis. . . (Genoa, 1654); and Experimenta nova anatomica. . . chyli motu (Amsterdam, 1661). An English trans. is New Antaomical Experiments by Which the Hitherto Unknown Receptacle of the Chyle and the Transmission From Thence to the Subclavial Veines by the Now Discovered Lacteal Chanels of the Thorax Is Plainly Made Apear in Brutes . . . Being an Anatomical Historie Publickly Propos’d by Thomas Bartoline to Michael Lysere, Answering (London, 1653).

Other works are Brevis destructio, seu litura responsionis Riolani ad ejusdem Pecqueti esperimenta per Hyginum Thalassium (Paris 1655; Amesterdam, 1661), which is also found in Siboldus Hemsterhuys, ed., Messia aurea, seu collectanea anatomica. . . (Leiden, 1654; Heidelberg, 1659); in Daniel Le Clerc and J. J. Manget, eds., Bibliotheca anatomica (Geneva, 1685); and in Thomas Bartholin, Anatomia . . . tertium ad saguinis circulationem reformata . . . (Laon, 1651); “Lettre de M. Pecquet à M. de Carcavi touchant une nouvelle découverte de la communication du canal thoracique avec la veine émulgente,” in Journal des sçavans (4 Apr. 1667), 53–56; and Réponse . . . à la lettre de Mr.l’ Abbé Mariotte sur une nouvelle découverte touchant la uveü (Paris, 1668); and “Lettres écrites par MM. Mariotte, Pecqet et Perrault sur le sujet d’une nouvelle découverte touchant la vueüe faite par M. Mariotte,” in Recueil de plusieurs traitez de mathématuques de l’ Académie royale des sciences (Paris, 1676).

II. Secondary Literature. Three are unsigned aricles on Pecquet in A. L. Bayle and A. J. Thillaye, eds. Biographie médicale, II (Paris, 1855), 13–14; J. E. Dezeimeris, Dictionnaire historique de la médecube ancience et moderne,III (Paris, 1836). 689; Dictionnaire historique de la médecine ancienne et moderne, III (Mons, 1778), 507–508; Michaud, ed., Biographie universelle ancienne et moderne, XXXIII , 247–249; and Nouvelle bigraphie médicale depuis les temps les plus reculés jusqu’au nos jours,XXXIX (Paris, 1863), 443–444.

Bartholin’s fundamental investigations on the human lymphatics in 1652–1653 were completed by those made independently in 1651 by Olof Rudbeck. On this subject see V. Maar, “Thomas Bartholinus,” in Janus, 21 (1916), 273–301, and Axell Garböe, “Thomas Bartholin,” I-II . On Rudbeck see Annals of Medical History (1928).

See also Berchon, “Victor Hugo et la découverte de Pecquet,” in Chronique médicale, 21 (1914), 429–431; A. Chéreau, “Pecquet,” in Dictionnarie encyclopédique des sciences médicales, XXII (Paris, 1886), 202; J Delmas, “Pecquet,” in Médecins célébres (Paris, 1947), 94; R. Desgenettes, “Pecquet,” in Dictionnaire des sciences médicales—biographie médicale, VI (Paris, 1824), 384–385; P. Gilis, “Pecquet,” in Bulletin de la Société des sciences médicales et biologiques de Montpellier, 3 (1921–1922), 32–60, with portrait; in Montpellier médical,43 (1921), 627–628; and Normandie médicale, 32 (1922), 141–156, 177–191; E. Hintzsche, “Anatomia animata,” in Revue Ciba,64 (1948), 2398–2399; Georges Laux, “Tricentenaire de la thèse de J. Pecquet. L’oeuvre anatomique,” in Séance publique de la section, montpellieraine de la Société française d’histoire de la médecine, 31 Mars 1952 (Montpellier, 1952); and “Jean Pecquet. Son oeuvre anatomique,” in Monspelliensis Hippocrates, no. 37(1967), 7–12, with portraits and facsimiles; Jean Lucq, “Jean Pecquet. 1622–1674,” a thesis at the University of Paris (1925, no. 22); Pagel, “Pecquet,” in Biographisches Lexicon der hervorragenden Ärzte, IV (Berlin Vienna, 1932), 543; the anonymous “Jean Pecquet,” in Progrès médical, ill. supp. no. 5 (1926), 39–40; P. Rabier, “Le centenaire de Pecquet,” in Paris médical, 46 (supp.) (1922), 171–173; and C. Webster, “The Discovery of Boyle’s Law and the Concept of the Elasticity of Air in the Seventeenth Century,” in Archive for History of Exact Sciences,2 (1965), 441–502, with illustrations and references.

Pierre Huard
Marie-JosÉ Imbault-Huart