WOLFF, CASPAR FRIEDRICH

(b. Berlin, Germany, 18 January 1734; d. St. Petersburg, Russia [now Leningrad, U.S.S.R.], 22 February 1794)

biology.

Wolff was the son of Johann Wolff, a tailor who moved to Berlin in the late seventeenth or early eighteenth century, and Anna Sofia Stiebeler. He studied medicine at the Medical-Surgical College in Berlin (1753– 1754) and in 1755 enrolled at the University of Halle; his dissertation, Theoria generations (1759), was criticized by Haller and Bonnet. On behalf of the Prussian Academy of Sciences, Euler attempted unsuccessfully in 1760– 1761 to obtain for Wolff a post at the St. Petersburg Academy of Sciences. In 1761 Wolff became a field doctor in the Prussian army, which was then at war with Russia; and he also lectured in anatomy at the Breslau Military Hospital. His attempts in 1762 and 1764 to obtain permission to lecture in Berlin were opposed by the professors of the Medical-Surgical College, who had guild privileges to teach medicine.

After returning to Berlin in 1763, Wolf gave private lectures in anatomy, physiology, and medicine. The following year he restated his theory of generation and replied to Haller’s and Bonnet’s criticism in Theorie von der Generation further decreasing his chances of obtaining a professorship. In 1766 he accepted an invitation from the St. Petersburg Academy of Sciences, extended at Euler’s initiative, to join the department of anatomy. He traveled to Russia with his wife in May 1767 and later that year presented to the Academy “De formatione intesti-norum praecipue.” During the next twenty-seven years he published thirty-one memoirs in the Academy’s Proceedings, including several that were devoted to anatomical research on the muscles of the heart and on connective tissue. He paid special attention to the study of human monstrosities, which were collected in the Academy’s anatomical cabinet (which Wolff directed) of the Kunstkammer. Surviving manuscripts indicate that Wolff prepared a major work on the “theory of monsters,” in which he attempted to systematize his epigenetic ideas. His sudden death from a brain hemorrhage prevented his completing this project.

Wolffs fundamental achievement was the refutation of the theory of preformation, which considered the development of an organism to be simply the expansion of an invisible, transparent, fully formed embryo. Wolff”s detailed studies of plants led him to establish that growth takes place at the apex of any axial organ, in the so-called growing point. In the cabbage and chestnut he observed the gradual formation of the leaf layers and the appearance of veins and petioles. In establishing that the blossom is a modified leaf, Wolff anticipated the theory of metamorphosis, formulated in 1790 by Goethe, according to which all the organs of a plant are the result of transformation of leaves.

In the chick embryo, Wolff followed the development of the heart and blood vessels, and studied the formation of the blood from “blood islets” and the development of the extremities, the mesonephros, and the intestines. He discovered only the embryonic (“primary”) kidneys, which become the final (“secondary”) metanephros. The primary kidneys which he discovered became known as Wolffian bodies and their ducts, Wolffian ducts. Using the example of the development of the intestine, Wolff established the principles of formation of organs from foliate layers, by means of such processes as proliferation, folding, and wrapping (for example, in tubes and cavities). He thus laid the foundations of the theory of embryonic layers.

Wolff also attempted to give a universal explanation of the developmental process of organs. Because sufficient knowledge of the cellular structure of organisms was lacking during his lifetime, Wolff believed that all growth originates in a liquid substance that is completely lacking in organic structure. In such an “inorganic substance,” he asserted, “bubbles” (vesicula), or “globules,” and vessels are formed. Of primary importance to Wolff was the search for that force which provides for the entry of juices into plants and “nutrient material” into the embryo, and that ensures its subsequent infiltration during the formation of the various parts. Early on Wolff asserted that the presence of an “essential force” (vis essentialis) and the “ability to solidify” (solidescibilitas) are sufficient to explain nutrition, growth, and development. By means of these two “capacities” he attempted to explain not only individual development but also the obvious differences between organisms —and even the distinction between the plant and animal kingdoms. Wolff later abandoned these ideas, postulating only that “the formation of organic bodies in general is caused by one natural force,” which inhabits the animal or plant substance (1768). In his last published treatise (1789), he concluded that the “essential force… consists in nothing other than in a certain special and definite kind of attractive and repulsive force.” However primitive these views, there is no basis for interpreting them either as vitalistic or animistic; and in his last treatise he spoke out categorically against identifying “essential force” with the anima of Stahl. He also vigorously denied Blumenbach’s concept of “formative tendency” ’(nisus formativus). In an unpublished treatise Wolff considered the soul to be “an extract of the brain and of the brain matter.” Asserting the material nature of the soul, Wolff held that it “is born together with the body, which it inhabits and with which it is connected, but which it does not preexist.”

Wolff’s works contributed to the development of embryology and especially to the work of Pander and Baer, both of whom repeated, confirmed, and continued his research.

BIBLIOGRAPHY

I. Original Works. Wolff’s dissertation. Theoria generationis (Halle, 1759), was followed by his polemical restatement, Theorie von der Generation in zwo Abhandlungen erklärt und bewiesen (Berlin, 1764); and a rev. and enl. Latin ed., by P. Meckel (Halle, 1774). Modern eds. include that of Paul Samassa, in German, Ostwalds Klassiker der Fxacten Wissenschaften nos. 84–85 (Leipzig, 1896); in Russian. Teroia zarozhdenia. A. E. Gaissinovitch, ed. (Moscow, 1950), with commentary, unpublished additions by Wolff, and complete bibliography of his writings; and a photo reprint of the 1759 and 1764 eds., in one vol. (Hildesheim, 1966).

Other works are “De formatione intesti—norum praecipue… Observationes, in ovis incubatis institutae,” in Novi commentarii academiae scientiarum imperialis Petropolitanae. 12 (1768), 403–507; and 13 (1769). 478–530 —a German ed., J. F. Meckel, trans., was published as Über die Bildung des Darmkanals im behrüteten Hühnchen (Halle. 1812); and Von der eigenthümlichen und wesentlichen Kraft der vegetabilischen, sowohl als auch der animalischen Substanz (St. Petersburg, 1789). The unfinished Objecta meditationum pro theoria monstrorum was published in Latin and Russian by T. A. Lukina (Leningrad, 1973).

A list of Wolff’s MSS at the Academy of Sciences in Leningrad was published by L. B. Modzalevsky, in Vestnik Akademii nauk SSSR, 3 , no. 3 (1933), 59–66.

II. Secondary Literature. Earlier sources on Wolff’s life and work include Alfred Kirchhonff, Die Idee der Pflanzen-Metamorphose bei Wolff und bei Göthe (Berlin, 1867); and “Caspar Friedrich Wolff. Sein Leben und seine Bedeutung für die Lehre von der organischen Entwicklung,” in Jenaische Zeitschrift für Naturwissenschaft, 4 (1868), 193–220; the excellent study by W. M. Wheeler, “Caspar Friedrich Wolff and the Theoria generationis,” in Biological Lectures. Marine Biological Laboratory, Woods Hole, Mass. for 1898 (Boston. 1899), 265–284; W. Waldeyer, “Festrede,” in Sitzungsberichte der Preussischen Akademie der Wissenschaften, 6 (1904). 209–226; J. Schuster, “Caspar Friedrich Wolff. Leben und Gestalt eines deutschen Biologen,” in Sitzungsberichte der Gesellschaft naturforschender Freunde zu Berlin (1937), 175–195; “Der Streit um die Erkenntnis des organischen Werdens im Lichte der Briefe C. F. Wolffs an A. von Haller,” in Sudhoffs Archiv für Geschichte der Medizin und der Naturwissenschaften, 34 (1941), 196–218; and L. Stieda, Biographisches Lexikon der hervorragenden Ärzte, V (Berlin-Vienna, 1934), 983–984, with brief bibliography of Secondary Literature.

More recent works are L. Y. Blyakher, Istoria embriologii v Rossii (“History of Embryology in Russia”: Moscow, 1955), 21–68; A. E. Gaissinovitch, C. F. Volf i uchenie o razvitii organizmov (“C. F. Wolff and the Theory of the Development of Organisms” Moscow, 1961), the most complete account of his life and work, with complete bibliography of his writings: B. E. Raykov, Ocherki po istorii evolyutsionnoy idei v Rossii do Darvina (“Sketches in the History of the Idea of Evolution in Russia Before Darwin”). I (Leningrad, 1947), 76–93; Russkie biologi-evolyutsionisty do Darvina (“Russian Evolutionary Biologists Before Darwin”), I (Leningrad, 1952), 165–193; and “Caspar Friedrich Wolff,” in Zoologische Jahrbücher, Systematik, ökologie und Geographie, 91 (1964), 555–626; and G. Uschmann, Caspar Friedrich Wolff. Ein Pionier der modernen Embryologie (Jena, 1955). Of the papers marking the 200th anniversary of the publication of Theoria generationis, the best is R. Herrlinger, “C. F. Wolffs Theoria generationis (1759). Die Geschichte einer epochemachenden Dissertation,” in Zeitschrift für Anatomie und Entwicklungsgeschichte, 121 (1959), 245–270.

A. E. Gaissinovitch

WOLFF, CASPAR FRIEDRICH

(b. Berlin, Germany, 18 January 1734; d. St. Petersburg, Russia [now Leningrad, U.S.S.R.], 22 February 1794)

biology.

For a detailed account of his life and work, see Supplement.