Driesch, Hans Adolf Eduard

views updated May 18 2018

Driesch, Hans Adolf Eduard

(b. Bad Kreuznach, Germany, 28 October 1867; d. Leipzig, Germany, 16 April 1941)

biology, philosophy.

Toward the end of the nineteenth century, when Hans Driesch entered upon his unique career, the German universities seemed to be in their prime and members of their scientific faculties were particularly preeminent in the natural sciences, including biology. Yet when Driesch chose his life style, he became an embryologist as an independent rather than as a professional investigator. He was a man of comfortable means, a cosmopolite, and a world traveler. He had no need, and at first no inclination, to join the academic hierarchy; he was not habilitated until twenty years after he had received his doctorate. While working as an amateur, he made numerous contributions of great originality and of far-reaching importance to the new science of experimental embryology. He was always theoretically inclined, and his experimental results turned him eventually toward philosophical explanations. He had already written, while still an experimental biologist, a number of metaphysical articles and books; and when he finally was habilitated, it was in natural philosophy. He became a professor of philosophy and, as such, the strongest proponent in our times of vitalism.

Driesch was the only child of Paul Driesch, a well-to-do Hamburg merchant who dealt in gold and silver wares, and the former Josefine Raudenkolb. He grew up in Hamburg, where he was first educated at a famous humanistic Gymnasium, Gelehrtenschule des Johanneums, founded by a friend of Martin Luther’s. In 1886 he spent two semesters at the University of Freiburg, studying with August Weismann in preparation for becoming a zoologist. He then became a student at the University of Jena, where he received his doctorate under Ernst Heinrich Haeckel in 1889; during the summer of 1888 he interrupted his zoological training to study physics and chemistry at Munich. For ten years after he received his degree he traveled extensively, usually with Curt Herbst, whom he had met at Jena in 1887; many of his scientific ideas were strongly influenced by Herbst’s. Driesch performed his most important experiments during these years; they were carried out principally, although not exclusively, at the internationally supported Zoological Station in Naples. He did his last experiments in 1909, the year in which he was habilitated in natural philosophy at the Faculty of Natural Sciences of Heidelberg, where he had settled in 1900. On 23 May 1899 he married Margarete Reifferscheidt; their children were Kurt (b. 1904) and Ingeborg (b. 1906), both of whom later became musicians.

Driesch became extraordinary professor at Heidelberg in 1912, accepted the ordinary professorship of systematic philosophy at Cologne in 1919, and became professor of philosophy at Leipzig in 1921. He was a visiting professor in China (Nanking and Peking) in 1922–1923, in the United States (University of Wisconsin) in 1926–1927, and in Buenos Aires in 1928. In 1933 he was prematurely placed in emeritus status by the National Socialists because of his lack of sympathy for their regime, but he continued to work until he died in 1941.

Driesch first became attracted to zoology through his mother’s collection of exotic birds and animals, maintained in an aviary and in vivaria in her home. He was inspired to specialize in embryology, as were many of his contemporaries, by Haeckel’s popular books. Driesch, however, lost interest in phylogeny by 1890. He himself chose the subject for his doctoral dissertation, which played down phylogenetic speculation in favor of an investigation of the laws governing the growth of hydroid colonies (1890, 1891). In the spring of 1891 he performed the experiment for which he is now best remembered, the separation of the blastomeres of the cleaving sea urchin egg.

Shortly before, in 1888, Wilhelm Roux had published the results of experiments showing that when one blastomere of the two-celled frog egg is killed, the remaining cell forms a half-embryo. Roux interpreted this as signifying that each cell is predestined, at the two-cell stage, to form only what it would have formed in the normally developing embryo. Richard and Oskar Hertwig, and later Theodor Boveri, had shaken sea urchin eggs to separate them into nucleated and nonnucleated fragments; Driesch adopted this method to separate the sea urchin blastomeres at the two-cell stage and found that in this egg, in contrast with that of the frog, each blastomere could form a whole, rather than a half, larva. Driesch interpreted these results as signifying that the fate of the cells is not fixed at the two-cell stage and that a cell can form parts that it does not normally form during development. The fate of a cell is a function of its position in the whole; its prospective potency, as Driesch was to put it a few years later (1894), is greater than its prospective significance. Furthermore, the cell not only forms parts that it would not have formed had the experiment not been performed; it also forms an organized, whole individual. It is, as Driesch was to call it, first in 1899, a harmonious equipotential system.

These interpretations were diametrically opposed to those of Roux, who considered that cells selfdifferentiate independently, forming a sort of mosaic that constitutes the embryo. Driesch’s discovery that the development of a cell is not fixed at the two-cell stage and that it can be altered confirmed experimentally that development is epigenetic and opened new paths for exploration by the developing science of experimental embryology. In particular, his emphasis on organic wholeness and his comparison of the prospective potency of a part with its prospective significance provided the conceptual framework for the organizer concept developed by Hans Spemann during the first third of the twentieth century.

Driesch eventually extended his original experiments on the sea urchin eggs by shaking them in calcium-free seawater, according to a method of Herbst’s, and separated the cells at later developmental stages. He also performed a corollary experiment, fusing two sea urchin embryos at the blastula stage to produce a single giant larva. He experimented also on eggs of other echinoderms and of ctenophores and ascidians, and he performed a number of experiments on regeneration in adult hydroids and ascidians. The philosophical implications of these experiments were later to influence Driesch’s thought profoundly; but in the meantime, during the latter part of the nineteenth century, he performed a number of other strictly embryological experiments of great import and influence in their time, although they are less frequently recalled than the blastomere separation.

Roux and Weismann had postulated that qualitatively unequal nuclear division and subsequent differential distribution of nuclear material to the cells are the prime factors responsible for the formation of particular embryonic parts by particular cells. If this explanation held true, Driesch reasoned, abnormal distribution of the nuclei in the cytoplasm should result in embryonic malformations. He tested this possibility (1892) by compressing sea urchin eggs between glass cover slips at the four-cell stage in order to alter the cleavage pattern. The third cleavage occurred under pressure. The cytoplasm was deformed, with the nuclei displaced and atypically distributed through it. Yet the larvae that developed from the compressed eggs were normal, and Driesch knew that this meant that all the nuclei were equivalent. As Herbst said, “Expressed in terms of modern genetics, this signifies that all the nuclei contain all the genes” (“Hans Driesch als experimenteller und theoretischer Biologe,” p. 115).

Driesch had great interest in the mode of nuclear function. He postulated (1894) that factors external to a cell influence its cytoplasm, which in turn influences the nucleus to produce substances that affect the cytoplasm. Furthermore, he postulated that the influence of the nucleus on the cell body is mediated through enzymes (ferments, in the terminology of his times); these concepts were widely disseminated and extremely influential in their day.

Another experiment performed by Driesch on sea urchin eggs, of equal theoretical importance and influence, was one in which he shook sea urchin larvae at the stage when the primary mesenchyme cells were organizing themselves into two clumps, preparatory to developing the larval skeleton. After their displacement by the shaking, the mesenchyme cells returned to their original positions. Driesch believed that they reaggregated there under the influence of the ectoderm and interpreted this in terms of the ability of the mesenchyme cells to react to tactile stimuli from the ectoderm (1896). This is very close to the concept of induction; in 1894 Driesch had written at great length about the possibilities of embryonic induction, including chemical induction and contact induction, in the widely read monograph Analytische Theorie der organischen Entwicklung.

Driesch published his first wholly theoretical pamphlet in 1891; in it he expressed his desire to explain development in terms of mechanics and mathematics. In the Analytische Theorie der organischen Entwicklung he was still mechanistic in outlook. As early as 1892, however, he had mentioned, in an experimental paper, the possibility that vitalistic interpretation might be compatible with scientific methodology; by 1895, according to his own testimony, he was a convinced vitalist. He despaired of explaining on a mechanistic basis the ability of half of a two-celled egg to form a whole larva, for he could not envisage a machine that could divide itself into two machines, each able to reconstitute itself into a whole. During the first decade of the new century he found himself obliged to invoke an agent-outside-the-machine (for which he borrowed Aristotle’s word “entelechy”) as a regulator of organic development. Although he believed the entelechy to be a vital agent indefinable in terms of physics and chemistry, he thought its action was somehow brought about by the formation or activation of enzymes (ferments), and he laid strong emphasis on the importance of enzymes as regulatory agents in development.

Driesch was invited to deliver the Gifford lectures in natural theology at the University of Aberdeen in 1907 and 1908. These lectures, first published in 1908 in Driesch’s own excellent English under the title Science and Philosophy of the Organism, summarized his experiments and the philosophical conclusions to which they led. Driesch later wrote many philosophical articles and books on organic form and organic wholeness, on the mind-body problem, and so forth. As a systematic philosopher he devoted considerable attention to both logic and metaphysics; as a metaphysician, he was strongly influenced by Kant. He also became interested in parapsychology; when he applied for permission to leave Germany to preside at a meeting of the International Society for Psychic Research in Oslo in 1935, he was deprived of his passport by the Nazis.

Driesch received many honors, including honorary degrees from Aberdeen, Hamburg, and Nanking. In honor of his sixtieth birthday, in 1927, eighteen years after he had performed his last experiment, two volumes of Wilhelm Roux Archiv für Entwicklungsmechanik der Organismen, including forty-eight articles, were dedicated to him. In his introduction to the Festschrift, Spemann wrote: “If Wilhelm Roux’s systematic mind discovered and staked out for us a new field of investigation, Driesch’s statements of its problems widened its horizons immeasurably” (p. 2). He placed Driesch’s work, to which he owed so much, in proper perspective.

Although Driesch’s experiments were ingeniously conceived, he was not particularly deft at carrying them out, a deficiency that he recognized and regretted. The biological interpretations of some of his experimental results, particularly those on later cleavage stages of the sea urchin, were subsequently shown to have been erroneous. Nevertheless, the principal conclusions drawn from his early experiments still hold. They made a positive contribution to the ongoing progress of experimental and analytical embryology that cannot be minimized, even though in his later days Driesch chose what was to him the vitalistic imperative.

BIBLIOGRAPHY

I. Original Works. The article by Herbst (below) includes a bibliography of 130 items by Driesch, classified into two categories (descriptive and experimental, and biotheoretical). The book edited by Wenzl (below) includes a bibliography of 289 items by Driesch, arranged chronologically. The articles and books listed below deal principally with Driesch’s experiments and their interpretations: “Tektonische Studien an Hydroidpolypen,” in Jenaische Zeitschrift für Naturwissenschaft, 24 (1890), 189–226; “Tektonische Studien an Hydroidpolypen. II. Plumularia und Aglaophenia. Die Tubulariden. Nebst allgemeinen Erörterungen über die Natur tierischer Stöcke,” ibid., 657–688; “Entwicklungsmechanische Studien. I. Der Werth der beiden ersten Furchungszellen in der Echinodermenentwicklung. Experimentelle Erzeugung von Theil-und Doppelbildungen. II. Ueber die Beziehungen des Lichtes zur ersten Etappe der thierischen Formbildung,” in Zeitschrift für wissenschaftliche Zoologie, 53 (1891), 160–184; “Heliotropismus bei Hydroidpolypen,” in Zoologische Jahrbücher, Abteilung für Systematik... 5 (1891), 147–156; Die mathematisch-mechanische Betrachtung morphologischer Probleme der Biologie. Eine kritische Studie (Jena, 1891); “Tektonische Studien an Hydroidpolypen. III (Schluss). Antennularia,” in Jenaische Zeitschrift für Naturwissenschaft, 25 (1891), 467–479; “Entwicklungsmechanische Studien. III. Die Verminderung des Furchungsmaterials und ihre Folgen (Weiteres über Theilbildungen). IV. Experimentelle Veränderungen des Typus der Furchung und ihre Folgen (Wirkungen von Wärmezufuhr und von Druck). V. Von der Furchung doppeltbefruchteter Eier. VI. Ueber einige allgemeine Fragen der theoretischen Morphologie,” in Zeitschrift für wissenschaftliche Zoologie, 55 (1892), 1–62; Die Biologie als selbstständige Wissenschaft (Leipzig, 1893); “Entwicklungsmechanische Studien. VII. Exogastrula und Anenteria (über die Wirkung von Wärmezufuhr auf die Larvenentwicklung der Echiniden). VIII. Ueber Variation der Mikromerenbildung (Wirkung von Verdünnung des Meereswassers). IX. Ueber die Vertretbarkeit der ‘Anlagen’ von Ektoderm und Entoderm. X. Ueber einige allgemeine entwicklungsmechanische Ergebnisse,” in Mitteilungen aus der Zoologischen Station zu Neapel, 11 (1893), 221–254; “Zur Theorie der tierischen Formbildung,” in Biologisches Zentralblatt, 13 (1893), 296–312; “Zur Verlagerung der Blastomeren des Echinideies,” in Anatomischer Anzeiger, 8 (1893), 348–357; Analytische Theorie der organischen Entwicklung (Leipzig, 1894); “Von der Entwickelung einzelner Ascidienblastomeren,” in Archiv für Entwicklungsmechanik der Organismen, 1 (1895), 398–413; “Zur Analyse der ersten Entwickelungsstadien des Ctenophoreies. I. Von der Entwickelung einzelner Ctenophorenblastomeren. II. Von der Entwickelung ungefurchter Eier mit Protoplasmadefekten,” ibid., 2 (1896), 204–224, in collaboration with T. H. Morgan; “Die taktische Reizbarkeit von Mesenchymzellen von Echinus microtuberculatus,” ibid., 3 (1896), 362–380; “Betrachtungen über die Organisation des Eies und ihre Genese,” ibid., 4 (1897), 75–124; “Studien über das Regulationsvermögen der Organismen. 1. Von den regulativen Wachstums- und Differenzirungsfähigkeiten der Tubularia,” ibid., 5 (1897), 389–418; “Ueber rein-mütterliche Charaktere an Bastardlarven von Echiniden,” ibid., 7 (1898), 65–102; Die Lokalisation morphogenetischer Vorgänge. Ein Beweis vitalistischen Geschehens (Leipzig, 1899), also in Archiv für Entwicklungsmechanik der Organismen, 8 (1899), 35–111; “Studien über das Regulationsvermögen der Organismen. 2. Quantitative Regulationen bei der Reparation der Tubularia. 3. Notizen über die Auflösung und Wiederbildung des Skelets der Echinidenlarven,” ibid., 9 (1899), 103–139; “Studien über das Regulationsvermögen der Organismen. 4. Die Verschmelzung der Individualität bei Echinidenkeimen,” ibid., 10 (1900), 411–434; “Studien über das Regulationsvermögen der Organismen. 5. Ergänzende Beobachtungen an Tubularia,” ibid., 11 (1901), 185–206; “Studien über das Regulationsvermögen der Organismen. 6. Die Restitutionen der Clavellina lepadiformis,” ibid., 14 (1902), 247–287; “Studien über das Regulationsvermögen der Organismen. 7. Zwei neue Regulationen bei Tubularia,” ibid., 532–538; “Ueber Aenderungen der Regulationsfähigkeit im Verlauf der Entwicklung bei Ascidien,” ibid., 17 (1903), 54–63; “Ueber das Mesenchym von unharmonisch zusammengesetzten Keimen des Echiniden,” ibid., 19 (1905), 658–679; Der Vitalismus als Geschichte und als Lehre (Leipzig, 1905); “Regenerierende Regenerate,” in Archiv für Entwicklungsmechanik der Organismen, 21 (1906), 754–755; The Science and Philosophy of the Organism. The Gifford Lectures Delivered Before the University of Aberdeen in the Year 1907 [and 1908], 2 vols. (London, 1908; 2nd ed., 1 vol., 1929); “Zwei Mitteilungen zur Restitution der Tubularia,” in Archiv für Entwicktungsmechanik der Organismen, 26 (1908), 119–129; “Neue Versuche über die Entwicklung verschmolzener Echinidenkeime,” ibid., 30 , pt. 1 (1910), 8–23; and Lebenserinnerungen. Aufzeichnungen eines Forschers und Denkers in entscheidender Zeit (Basel, 1951).

Later philosophical and theoretical articles are listed in the bibliographies by Herbst and Wenzl.

II. Secondary Literature. Selected writings about Hans Driesch, his work, and his thought are Margarete Driesch, “Das Leben von Hans Driesch,” in Hans Driesch, Persölichkeit und Bedeutung für Biologie und Philosophie von heute..., A. Wenzl, ed. (Basel, 1951), pp. 1–20; Curt Herbst, “Hans Driesch als experimenteller und theoretischer Biologe,” in Wilhelm Roux Archiv für Entwicklungsmechanik der Organismen, 141 (1941–1942), 111–153; and E. Ungerer, “Hans Driesch. Der Naturforscher und Naturphilosoph (1867–1941),” in Naturwissenschaften, 29 Jahrgang (1941), 457–462.

In addition, the work edited by Wenzl, cited above, includes a bibliography of other articles on Driesch and his work, p. 206. The Festschrift referred to in the text, dedicated to Driesch and containing 48 articles in his honor, is Wilhelm Roux Archiv für Entwicklungsmechanik der Organismen, 111–112 (1927).

Jane Oppenheimer

Complete Dictionary of Scientific Biography

Driesch, Hans (1867-1941)

views updated May 14 2018

Driesch, Hans (1867-1941)

Embryologist, professor of philosophy at the University of Leipzig, pioneer in many domains of science, and one of the most influential psychical investigators in Germany. Driesch was born in Bad Kreuznach, Germany, October 28, 1867, and had a distinguished academic and scientific career.

In his Philosophie des Organischen (1905) he expresses the opinion that behind psychic phenomena there may be a truth; and in his Wirklichkeitslehre (1917) he states, referring to the work of the Society for Psychical Research, that anyone who declares these things impossible has given up the right to be listened to by serious people.

He mainly meant mental phenomena, but he included physical phenomena as well after his sittings with Willi Schneider in 1922. In his report he saw no reason to deny the objectivity and the genuineness of the phenomena and in a lecture before the London University in 1924 he declared that "the actuality of psychical phenomena is doubted today only by the incorrigible dogmatist."

In the second edition of his Ordnungslehre (1926) a special part is devoted to parapsychology and parapsychophysics. In Grundprobleme der Psychologie, published in the same year, the problems also receive elaborate discussion. In answer to a questionnaire sent out by Oreste Parfumi, published in Luce e Ombra (1926), he states: 1. The mediumistic phenomena are not effects of simple hallucination; 2. It appears to me that they depend exclusively upon the organism of the medium; 3. The spirit theory does not seem to me proven; but spiritism, were it proven, would be a scientific theory. In acknowledgment of Driesch's contribution to psychical research the Society for Psychical Research elected him to the presidential chair for 1926-27, the first German so honored.

Driesch lectured widely on philosophy at universities throughout the world and associated with such pioneers of psychical research as Gustave Geley, Eugene Osty, Baron von Schrenck-Notzing, Sir Oliver Lodge, and Walter Franklin Prince. He also sat with such famous mediums as Willi and Rudi Schneider, "Margery" (Mina Crandon ), and Gladys Osborne Leonard.

Driesch retired from his position as lecturer at the University of Leipzig in 1933 under pressure from the Nazis following his support of Jewish scientists. Thereafter he devoted time to his writings, which include a translation into German of J. B. Rhine 's book New Frontiers of the Mind (1938). He died April 16, 1941, at Leipzig.