ROUGET, CHARLES MARIE BENJAMIN

(b. Gisors, France, 19 August 1824; d. Paris, France, 1904)

physiology, histology.

The son of a surgeon in the armies of Napoleon, Rouget attended the Collège Sainte-Barbe and received medical training at the teaching hospitals of Paris. In 1860 he was appointed to the chair of physiology at the University of Montpellier, where, it is said, he was an efficient and inspiring teacher. In 1879 he was one of two candidates whose names were submitted by the Académie des Sciences for the vacant chair of physiology in the Muséum d’Histoire Naturelle. Although unsuccessful on this occasion, he was appointed to the professorship when it fell vacant again shortly afterward, and held it until his retirement in 1893. His colleagues specially remembered him as a brilliant histologist.

In summarizing Rouget’s achievement one is faced with the same difficulty that beset the Academy when they were preparing his citation for the La Caze Prize of 1887. On account of the extent and variety of his published writings it was almost impossible to decide what work was most representative of his contribution to science. There are few instances in which his research is not characterized by some degree of originality. His interest in animal starch, on which he first wrote in 1859, was obviously informed by Claude Bernard’s discovery that glycogen functions in the nutritive process by making sugar available; but the view that diabetes mellitus was caused by some internal nutritive disorder was largely Rouget’s own speculation.

Animal reproductive organs and functions were among Rouget’s recurring interests. Although not wholly original, one of his finest early papers, published in 1856, described the function of the gubernaculum testis in guiding the descent of the testes through the inguinal canal. He gave clear and tolerably accurate accounts of vascular engorgement of erectile tissue and of muscle contraction of the seminal glands in sexual phenomena. He also gave plausible explanations of ovulation and menstruation; of how the ovules, fertile or otherwise, find their way into the funnel of the oviduct; and of why menstrual hemorrhage occurs only in humans and other primates. His interest in sexual phenomena was partly an outgrowth of his speculation on the mechanism of erectility, and in 1868 he published “Erectile Movements,” in Archives de physiologie, in which he explained that erectility is not, like contraction, a “simple act of the tissue,” but the capacity of the tissue to hold unusual quantities of blood forced into its reservoirs by the constriction of blood vessels. As a result of his microscopic research on the female gonads, especially during 1879, he confirmed the presence of primordial egg cells in the ovaries of newly born mammals.

Rouget was especially interested in three topics: the eye, contractile tissue, and nerve endings. He wrote extensively on the eye, finally submitting a “new theory of vision.” One of his more original contributions concerned visual accommodation, which is the automatic adjustment of the curvature of the lens so that a distinct image will be formed on the retina. The nearer the object, the greater the convexity of the lens. The lens is suspended from a ring of thickened tissue (the ciliary process) whose circular contraction reduces the tension on the suspensory ligament and enables the lens, with its natural elasticity, to assume a more convex shape. Within the ciliary process are two sets of muscle fibers; one set runs meridionally and the other circularly. Rouget was not the first to discover the circular muscles, and he lost no time in refuting the suggestion that he had plagiarized some of the work of Johannes Müller. Rouget was more original in explaining how the circular fibers are responsible for reducing the diameter of the ciliary margin for visual accommodation, and on the whole his account is correct. Rather less plausibly, he also assigned a role to the blood vessels. As the circular muscles contract, he argued, the constriction of the veins, returning from the iris, induces an engorgement in the ciliary tissue, and the turgidity assists in the reduction of the diameter of the annular rim.¹ (Else where Rouget used the same explanation of engorgement as part of his explanation of glandular contraction.)

Rouget’s interest in the phenomenon of muscle contraction led him to put forward a strange theory. In 1861 he challenged Brücke’s finding that because the alternate bands of striped muscle fiber exhibit different optical properties, the cause of muscle contraction is probably chemical. Rouget suggested that these effects were due to the physical arrangement of the inner parts of the fiber. In 1863 Rouget wrote, “If smooth fibers can become striped in consequence of the foldings, which are the basis of their contraction, striped fibers can become completely smooth by forcible extension, and the mechanical conditions of their contraction are fulfilled by foldings similar to [those] seen in contracted smooth fibers.” Briefly, his developed theory of muscle contraction, first published in 1866, envisaged the striped fibrils—that is, the longitudinal myofibrils within voluntary muscle fibers—as resilient helices, the contraction of which was due to simple elasticity but the extension of which was a function of the energy derived ultimately from nutrition.² As a model for this physiological theory, he chose the mechanism of the coiled, ciliated process of the Vorticella.³ Obviously he was drawn into untenable views about muscle action in relation to nervous excitation.

Capillary contractility is phenomenon closely linked with Rouget. Although people were aware of the periodic changes in the caliber of blood capillaries, there was no evidence of any contractile apparatus, such as are found in the middle coat of arteries. Examining the capillaries of the hyaloid membrane of the eye of a frog. Rouget found on the outside, endothelial surface of the capillary, isolated nuclei surrounded by protoplasm, the ramifications of which extend like rings around the vessel.⁴ Having observed what he took to be constriction of these ramified extensions on the capillaries of newt larvae, he concluded that they are modified smooth muscle cells. Since then, there has been a continued controversy on the function of the “cells of Rouget,” and the topic was still a living issue in the 1960’s, the available information indicating that although they were prototypes of smooth muscle-fiber, it was very unlikely that they were actively contractile.

Rouget’s research on nerve endings has also been of permanent value. In 1866 and 1868 he published findings on the sensory receptors of the skin, particularly the receptors associated with Filippo Pacini and Wilhelm Krause, in which he adumbrated, though in terms that would be rejected today, that the capsule of the latter is not independent tissue, as Koelliker had maintained, but a development of the myelin sheath of the supplying sensory nerve.⁵ One of Rouget’s last papers was on the termination of sensory nerve fibers in skeletal muscle.⁶ Some of his finest microscopic research was more particularly concerned with end plates.⁷ His descriptions of motor plates are mainly elaborations of the histological research of Doyère, Quatrefages, and Kühne, although he added considerable detail to their accounts. Thus he described how the “nerve tube” (axon) with its contour (Schwann’s sheath) reaches the surface of the muscle, and then opens out, the nerve substance putting itself into contact with the contractile fibers of the muscle, and the contour of the “nerve-tube” mingling with the sarcolemma. He identified the end of the nerve plate as a disk of granular matter (cytoplasm), with several nuclei, which was extended on the surface of the muscle fibrils. He failed, however, to appreciate the significance of the synaptic cleft.

One outgrowth of Rouget’s interest in nerve endings is seen in his papers on the electric organs of certain fishes. Thus he recorded the resemblance between the pattern of nerve threads that supply the electroplates, and those seen in motor nerve endplates. While not going so far as to suggest that the electroplates of the Torpedo are modified muscle tissue, he maintained that the electrical discharge produced by the nerves was merely an outflow of the energy that normally would lead to muscle movement.

NOTES

1. “Recherches anatomiques et physiologiques sur les appareils érectiles, …” in Comptes rendus hebdomadaires des séances de l’ Académie des sciences, 42 (1856), 937–941.

2. “Note sur des photographies microscopiques relatives à la structure des muscles et aux phénomènes de la contraction musculaire,” ibid., 62 (1866), 1314–1317.

3. “Note sur les phénomènes de contraction musculaire chez les vorticelles,” ibid., 64 (1867), 1128–1132.

4. “Note sur le développement de la tunique contractile des vaisseaux,” ibid., 79 (1874), 559–562.

5. “Sur la structure intime des corpuscules nerveux de la conjonctive et des corpuscules du tact chez l’homme,” ibid., 66 (1868), 825–829.

6. “Terminaison des nerfs musculaire sur les faisceaux striés,” ibid., 123 (1896), 127–128.

7. “Note sur la terminaison des nerfs moteur dans les muscles,” ibid., 62 (1866), 1377–1381.

BIBLIOGRAPHY

Material on Rouget is remarkably scant. See the obituary, M. Nestor Gréhant, “Charles Rouget, notice necrologique,” in Nouvelles archives du Muséum d’histoire naturelle, 6 (1904), iii. Information on Rouget’s earlier career is in the autobiographical Notice à l’appui de la candidature de M. le Dr. Charles Rouget à la chaire dephysiologic vacante à la Faculté de Médecine de Montpellier (Paris, 1860). For an appraisal of Rouget’s contribution to medicine, see the citation “Prix L. La Caze,” in Comptes rendus hebdomadaires des séances de l’Académie des sciences, 105 (1887), 1372. A catalog of Rouget’s more important publications is “Liste des ouvrages et mémoires publiés par M. Ch. Rouget,” in Nouvelles archives du Muséum d’histoire naturelle, 6 (1904), viii–xiii.

A. E. Best