POURFOUR DU PETIT, FRANçOIS

(b. Paris, France, 24 June 1664; d. Paris, 18 June 1741)

physiology, surgery.

Although he is said to have shown a flair for science, it would appear that the early, conventionally classical education of Pourfour du Petit was something of a failure. On leaving school, therefore, he traveled and undertook private study before enrolling at the University of Montpellier, from which he received his medical degree in 1690. Before practicing, however, Pourfour du Petit continued his medical and scientific studies in Paris, and completed his surgical training at the Charité hospital. For extended periods until the Treaty of Utrecht (1713), he served as physician-surgeon in the armies of Louis XIV, and it was during this war service that he carried out some of his most important physiological investigations. On leaving the army, Pourfour du Petit returned to Paris and established himself as an eye specialist, although he was also esteemed for his more generally scientific pursuits; and in 1722 he was elected as a member of the Académie des Sciences.

Apart from skillfully removing cataracts and designing ophthalmic instruments, Pourfour du Petit is known for a number of important anatomical discoveries, including that of the canal between the anterior and posterior suspensory ligaments of the lens of the eye.

The physiological experiments with which Pourfour du Petit is especially associated were carried out at Namur between 1710 and 1712, and at Paris during the mid-1720’s. In Trois leitres d’un médecin (1710) he described the head wounds and symptoms of paralysis of soldiers brought to him as patients. After many observations and postmortem dissections, the results of which he confirmed on dogs, he concluded that the movements of a limb are effected by animal spirits supplied by the side of the brain opposite the limb and that paralysis is complete only after the destruction of the contralateral corpus striatum. Pourfour du Petit’s other experiments were concerned with the origin of the sympathetic—or, as it was called then, intercostal—nerve. Through an excusable misunderstanding, seventeenth-century anatomists, including Thomas Willis, the leading English authority on the anatomy of the brain and nervous system, conceived this nerve chain as an outflow of the fifth and sixth cranial nerves. Through brilliant experiments on dogs, Pourfour du Petit showed that whatever the site of superficial origin of the sympathetic chain, it was not in the cranium. It is remarkable that, although his results were definitive, they were largely ignored until the nineteenth century.

The experiments on the sympathetic nerve were carried out in Namur at the Hôpitaux du Roi in 1712 and at the Académie des Sciences in 1725. Pourfour du Petit’s method of investigation, which originated at the time of Galen, consisted of dividing or ligating the trunk of a nerve and observing the syndromes. In this case the nerve selected was the extension of the sympathetic nerve in the neck, and the observed syndromes were those of the eye and surrounding tissue.

In the Namur experiments Pourfour du Petit observed, after cutting the cervical extension of the sympathetic nerve, that the affected eye became filled with tears and that the nictitating membrane encroached upon the cornea. This effect showed that the supply of “animal spirits” normally controlling these phenomena passes upward into the head through the nerve in the neck. The second series of experiments revealed other syndromes that had escaped his notice: inflammation of the conjunctiva and contraction of the pupil. Hence Pourfour du Petit concluded that the control of the nictitating membrane, of the lacrimal points (which normally drain off liquid from the eye), of the expansion of the pupil, and of the supply of blood to the eyeball originates in that nerve in the neck now recognized as the uppermost trunk of the orthosym-pathetic system. Thus he demolished the erroneous view that the sympathetic system was an outflow of one of the cranial nerves.

BIBLIOGRAPHY

I. Original Works. The primary sources for Pourfour du Petit’s original research are: Trois lettres d’un médecin sur un nouveau système du cerveau (Namur, 1710); “Mémoire sur les yeux gelés, dans lequel on détermine lagrandeur des chambres qui renferment l’humeur aqueuse” (1723), in Mémoires de l’Académie Royale des Sciences(1753), 38-54; “Mémoires sur plusieurs découvertes faites dans les yeux de l’homme, des animaux à quatre pieds, des oiseaux et des poissons“(1726), ibid. (1753), 69-83; “Mémoire dans lequel on détermine 1’endroit ou il fautpiquer 1’oeil dans l’opération de la cataracte“(1726), ibid., 262-272; “Mémoire dans lequel il est démontré que lesnerfs intercostaux fournisscnt des rameaux qui portent des esprits dans les yeux“(1727), ibid. (1739), 1-19 (this describes the series of experiments of 1712 and 1725 respectively); “Pourquoi les enfants ne voyent pas clair ènvenant au monde, et quelque temps après qu’ils sont nés” (1727), ibid., 246-257; “Démontrer que l’uvée est plane dans Phommc” (1728), ibid. (1753), 206-224; and “Différentes manières de connoitre la grandeur deschambres de I’humeur aqueuse dans les yeux de rhomme” (1728), ibid., 289-300 (this describes Pourfour du Petit’s ophthalmometer).

II. Secondary Literature. Biographies of Pourfour du Petit are in Biographie Universelle, L. G. Michaud, ed., XXXIII (Paris, 1823), 500-501; Poggendorff, II, 415; Biographisches Lexikon der hervorragenden Ärzte, August Hirsch, ed., IV (Uerlin-Vienna, 1932), 567-568. For a longer biography see J. J. Dortous de Mairan, Éloges des académiciens de i’ Académie royale des sciences morts dansles années 1714, etc. (Paris, 1747). Most general histories of medicine make passing reference to Pourfour du Petit’s neurological research. For a fuller study of his research see A. E. Best, “Pourfour du Petit’s Experiments on the Origin of the Sympathetic Nerve,” in Medical History, 13 (1969), 154-174.

A. E. Best