His, Wilhelm

(b. Basel, Switzerland, 9 July 1831; d. Leipzig, Germany, 1 May 1904)

anatomy, histology, embryology.

Wilhelm His was the son of Eduard His (whose name was Eduard Ochs until 1818, when he adopted his grandmother’s maiden name), a merchant in Basel and member of the court of appeals. His mother was the former Katharina La Roche. His grandfather, Peter Ochs, was a well-known Swiss politician and historian. His’s son, Wilhelm, Jr., who is occasionally confused with his father, was an internist in Berlin; he discovered the atrioventricular impulse-conducting system in the heart (bundle of His).

His began to study medicine at Basel in 1849 but transferred in the winter semester of 1849–1850 to the University of Bern and then, a year later, to the University of Berlin, where he studied under Johannes Müller and the embryologist Robert Remak. He attended the University of Würzburg in 1852–1853 for his clinical training, but the theoretical subjects taught there by Rudolf Virchow, Albert von Kölliker, and Franz Leydig attracted him far more than the clinical instruction. His also studied the writings of the physiologists Carl Ludwig and Hermann Lotze. He concluded his education with visits to Prague and Vienna, where he met Ernst von Brücke and the pathologist Karl Rokitansky. In the summer of 1854 he passed the physicians’ examination in Basel and thus had the right to practice medicine, but not until 1855 was he able to present his dissertation, which dealt with the normal and pathological histology of the cornea. In writing it His drew upon investigations that he had begun—at Virchow’s suggestion—while a student at Würzburg.

His spent the winter of 1855–1856 in Paris, where he was concerned primarily with chemistry. He attended the lectures given by Claude Bernard and met Berthelot and Brown-Sequard. Especially important for His at this time were the friendship and aid of two Swiss friends, the ophthalmologist Johann Friedrich Horner and the physicist Eduard Hagenbach. His returned to Basel, did research on his own, and in the winter semester of 1856–1857 qualified as a lecturer in anatomy and physiology. Hoping to become an assistant in the clinic of the Berlin ophthalmologist Albrecht von Graefe, His spent the summer of 1857 there as a visitor, working on the histology of the eye. During his stay he formed a close friendship with Theodor Billroth. In the fall of 1857 His was called to Basel to succeed Georg Meissner as professor of anatomy and physiology. Here, beginning in 1863, he was a member of the city parliament responsible for reorganizing the city following typhus and cholera epidemics; in 1865–1866 he was adviser on sewerage, cemeteries, and school hygiene.

In 1872 His succeeded Ernst Heinrich Weber in the chair of anatomy at the University of Leipzig. Like His in Basel, Weber had, until 1865, taught both anatomy and physiology; but in the latter year Carl Ludwig was named to the newly established chair of physiology. His’s first major task was to have a new anatomy laboratory built. When it opened in April 1875, it was one of the most modern laboratories for theoretical medicine.

His was vice-chancellor of University of the Basel in 1869–1870 and of the University of Leipzig in 1882–1883. He was a cofounder and several times president of the German Anatomical Society, perpetual secretary of the mathematics and physics section of the Royal Saxon Society of Sciences, and member of the brain research commission of the International Union of Academies. In addition, he played a major role in the reorganization of the Society of German Scientists and Physicians after 1889. In 1891, as president of this society, he settled—impartially—the disputes provoked by the new statutes that Virchow had proposed for it.

His’s scientific accomplishments lay in research and in the teaching of anatomy, histology, and embryology. In Basel he was at first concerned with histology and histochemistry, demonstrating, among other things, the existence of independent cornea cells. Other investigations dealt with the lymph vessels and the lymph glands and with the thymus. In 1863 he discovered the nerve plexus in the adventitia of the vessels. Toward the end of his life, when investigating embryological questions, he once again confronted histological and cytological problems. His contributed clearly formulated conceptions and doctrines to the vigorous debate over cell structure and cell division. He was especially concerned with the concept of amitosis, whose existence, in the literal sense of the word, he disputed.

In his investigations of the lymphatic system His arrived at certain ideas concerning the emergence of the body’s cavities and of their boundary layers. These ideas led to his first important embryological work, Die Häute und Höhlen des Körpers (1865). He began his account with Remak’s description of a third germ layer. Comparing it with the two others, His concluded that only those cavities formed of tissues arising from the mesoderm—vessels, serous cavities, joint cavities, synovial cavities, synovial cavities, and connective tissue interstices—should be designated “bodily cavities.” He contrasted the genuine epithelia of ectodermal and entodermal origin with the “nongenuine” epithelia, to which he gave the name they still bear, “endothelia.” The latter are most distinct in the blood vessels; they are totally absent in the interstices of the connective tissues. At this period the question of the structure and origin of the connective tissue was still unresolved. Studying it from the embryological point of view, His provided new insights. Henceforth he concentrated on embryology and in the following years produced numerous descriptive works on the development of individual organs or organ systems, especially of the vertebrate central nervous system and heart. On the basis of this work he was able to show (1883) that the nerve fibers are formed through the growth of the nerve cells, which he called “neuroblasts.”

His’s initial reflections on the mesoblast and connective tissue led, in addition, to the theory of the “parablast,” Through observations of embryonic ovaries he concluded that there is a genetic opposition between the primordial organ forms of the epithelia and the connective tissues. The latter, according to His, are formed by a distinct cell group, the “parablast,” and only later grow into the embryonic disk. This theory, published in 1866, produced a sensation and led to a series of investigations the results of which at first seemed to substantiate it. Finally, though, it was realized—not least through His’s own work—that the attempt to find a simple explanation of a differentiation process in early development again had to be abandoned. Following his Über die Bildung des Lachsembryos (1874), His furnished yet another interpretation of the processes occurring in the earliest stages of development of the vertebrate embryo: the concrescence theory. At first thought to be one of His’s important discoveries, it was later seen to be untenable. Nevertheless, it proved to be fruitful, for it stimulated a great many embryological investigations. The theory asserted that at first only the rudimentary form of the head lies in the middle of the embryonic disk; the rudimentary forms of the axial portions of the body emerge on the edge of the disk and are drawn into and fused in the middle only later.

Even before the formulation of the concrescence theory His had sought to develop simple explanations of developmental processes. For example, he had published a law of growth in Die erste Anlage des Wirbeltierleibes (1866–1868). According to the principle of the unequal growth of the embryonic disk, which can be considered as an imperfectly elastic body, purely mechanical convolution must occur. The first primitive organ thus to emerge, he contended, is the neural furrow, which finally closes to form the neural tube. In order to reduce embryonic development to a simple law of growth, His devoted considerable attention to mathematics. His friend Eduard Hagenbach contributed to His’s publication a mathematical analysis of the changes in shape that take place in an oval disk as a result of an oriented unevenness in its growth. On the basis of this conception of the general factors governing early development—according to which each organ arises at a specific location on the embryonic disk and, ultimately, on the unfertilized egg—His arrived at the principle of the embryo-forming regions.

His was thus the first scientist who sought to provide a causal explanation—in the modern sense—of embryonic development. Adolf Fick, the Swiss physiologist to whom His presented his theory of a law of growth, tried to persuade him to buttress his hypotheses with experiments; but His was reluctant to do so. Even later he clung to the method of analyzing and interpreting descriptive findings. Consequently it is not His, but Wilhelm Roux, who is considered the founder of the causal-analytic approach to embryology.

His presented his ideas on the development of the vertebrate embryo in a book dedicated to his Leipzig colleague Carl Ludwig; Unsere Körperform und das physiologische Problem ihrer Entstehung. Briefe an einen befreundeten Naturforscher (1874). The letters referred to in the subtitle were addressed to His’s nephew Johann Friedrich Miescher, the discoverer of nucleic acid. This publication faithfully characterizes the situation then existing in ontogenetic research and theory building. It was the period of controversy over the interpretation of developmental processes, a controversy between the new mechanistic-physiological approach and the phylogenetic point of view. The debate over the so-called “biogenetic law” was especially intense. Ernst Haeckel had declared that this law, recently discovered by Fritz Müller, was the unique foundation of embryology. The fourteenth letter in Unsere Körperform, a not completely unpolemical rebuttal of Haeckel’s theory, bore the title “Die Erklärung organischer Körperform durch das Descendenzprinzip, das ’biogenetische Grundgesetz’ und seine Begründung. Unmittelbare und mittelbare Erklärung.”

His was not alone in his rejection of Haeckel’s vies. The zoologist Alexander Goette also emphasized the difference between phylogenetic and physiological explanations of ontogeny. Unlike many of Haeckel’s other opponents, Goette and His were not anti-Drawinists, yet Haeckel presented them as such in his unusually harsh polemical reply to the findings and interpretations advanced—in a generally unpolemical manner—against his position (Zield und Wege der heutigen Entwicklungsgeschichte [1875]).

His’s work in embryology displayed new methodological conceptions. In 1866 he constructed the first microtome, which furnished an uninterrupted series of sections. He also built an embryograph, a prismatic drawing apparatus which permitted him to make exact drawings of the microscopic sections. In addition, His encouraged the introduction of photography into anatomy and the use of lantern slides in the classroom. His series of wax models of the development of fishes, chickens, and man became especially well-known. His’s use of topographical anatomy in his models also constituted an advance in anatomical instruction. And in connection with his presentation of human embryos (1880–1885) he introduced standardized charts into embryology.

His took his teaching duties very seriously; his address as vice-chancellor (1882) was entitled Über EntwicklungsverhäItnisse des akademischen Unterrichts. His’s efforts in anatomical nomenclature resulted in Nomina anatomica, which appeared in 1895, after many years’ work. Active in anthropology as well, he and Ludwig Rütimeyer wrote Crania Helvetica (1864). In 1895, under His’s supervision, the remains of Johann Sebastian Bach were identified and his burial place, hitherto lost and unknown, was rediscovered.

BIBLIOGRAPHY

I. Original Works. A complete list of His’s publications is in the obituary notice by Fick (see below). The most important are Die Häute und Höhlen des Körpers (Basel, 1865); Untersuchungen über die erste Anlage des Wirbeltierleibes (Leipzig, 1868); Unsere Körperform und das physiologische Problem ihrer Entstehung. Briefe an einen befreundeten Naturforscher (Leipzig, 1874); Anatomie menschlicher Embryonen, 3 vols. (Leipzig, 1880–1885); Die anatomische Nomenklatur (Leipzig, 1895); and Johann Sebastian Bach, Forschungen über dessen Grabstätte, Gebeine und Antlitz (Leipzig, 1895).

II. Secondary Literature See Rudolf Fick, “Wilhelm His,” in Anatomischer Anzeiger, 25 (1904), 161–208; Wilhelm His, Jr., Wilhelm His der Anatom. Ein Lebensbild (Berlin, 1931); Eugen Ludwig, ed., His der Ältere. Lebenserinnerungen und ausgewählte Schriften (Basel, 1965); and Unsere Körperform (see above), letters 2, 13, and 14.

Hans Querner