De Bary, (Heinrich) Anton

(b. Frankfurt-am-Main, Germany, 26 January 1831; d. Strassburg, Germany [now Strasbourg, France], 19 January 1888)

botany.

Heinrich Anton de Bary’s extensive and careful observations of the life histories of the fungi and his contributions on the algae and higher plants were landmarks in the increase of knowledge. Recognized as the foremost mycologist of his day, he is regarded as the founder of that branch of botany.

De Bary was one of ten children born to August Theodor de Bary, a physician, and Emilie Meyer de Bary. His parents encouraged his early propensities toward the study of natural science, and as a youth in Frankfurt he frequently joined the excursions of the active group of naturalists who collected specimens in the nearby countryside. Georg Fresenius, a physician who taught botany at the Senckenberg Institute and was an expert on the thallophytes, guided de Bary’s youthful interest in plants and in the examination of fungi and algae. After graduating in 1848 from the Gymnasium in Frankfurt, de Bary began the study of medicine at Heidelberg, continued at Marburg, and from 1850 pursued his studies’ at Berlin. There he had the opportunity to study under the botanist Alexander Braun, who as teacher and longtime friend communicated to him his own enthusiasm for botany. De Bary was a pupil also of Christian Gottfried Ehrenberg, known for his work on the Infusoria, and of the physiologist and comparative anatomist Johannes Müller, who exercised great influence on the students in his laboratory; de Bary was, some years later, to found laboratories in botany himself and to guide his students in a broad range of investigations. When de Bary received his degree in medicine at Berlin (1853) his dissertation was on a botanical subject and was entitled, De plantarum generatione sexuali. The same year he published a book on the fungi that caused rusts and smuts in plants.

De Bary entered the practice of medicine in Frankfurt but soon found himself drawn back to botany. Giving up his medical practice, he became Privatdozent in botany at the University of Tübingen. Here Hugo von Mohl, the noted plant anatomist, taught, and de Bary was for a while his assistant. In 1855 de Bary succeeded the botanist Carl von Naegeli at Freiburg im Breisgau.

De Bary established a botanical laboratory at Freiburg; it was the first laboratory of botany and represented a new development in botanical teaching, although its facilities were simple. Here he received the first of the many students who were to gather about him.

De Bary married Antonie Einert in 1861, and four children were born to them. In 1867 he succeeded D.F. L. von Schlechtendal at the University of Halle, where he established another botanical laboratory. Upon the death of Schlechtendal, who with Mohl had founded the Botanische Zeitung, de Bary became coeditor of the publication, and he served at times as sole editor. His first paper had appeared in this journal when he was a medical student and through it—both editorially and as a contributor—he exercised an important influence upon the field of botany.

After the Franco-Prussian War, de Bary was appointed professor of botany at the rechartered University of Strassburg and was appointed its first rector by unanimous vote. The well-appointed botanical institute that he founded there attracted students from Europe and America, and he encouraged them to pursue a diversity of interests. He participated in the activities of various botanical societies while continuing in his editorial capacities. He remained at Strassburg until his death.

De Bary clarified the understanding of the life histories of various fungi at a time when they were still considered by some to arise through spontaneous generation. In 1853, in Untersuchungen über die Brandpilze, writing on the fungi that produced rusts and smuts in cereals and other plants, de Bary had already come to the conclusion that these fungi were not the products of the cell contents of the affected plants, nor did they arise from the secretions of sick cells. In his view, they were like other plants, and their developmental histories would bear examination. The question of the origin of plant diseases was most pressing at that time, since fungous diseases, particularly the potato blight, had recently caused sweeping crop devastation with severe economic consequences. Although it was generally acknowledged that plants had parents like themselves, the fungi nevertheless seemed to some observers to present exceptions, and it was noted that they often occurred in association with putrefaction and decay. Much as M. J. Berkeley had insisted in 1846 that the fungus found in potato blight was the cause of the disease, de Bary declared in this early work that the rust and smut fungi were the causes of the pathological changes in diseased plants, and not their results, and that the Uredinales and Ustilaginales were truly parasites.

Until this time the origins and relationships of the fungal stages that had been distinguished were poorly understood, and appearances had been confusing to taxonomists. The importance of following plant life histories was underscored by Louis and Charles Tulasne’s recognition of pleomorphism in the fungi; they showed that certain forms which had been classified as separate species actually represented successive stages of development and might even originate from the same mycelium. De Bary continued with a broad range of contributions to morphology.

From his studies of the developmental history of the Myxomycetes, which included the slime molds, de Bary concluded that they ought correctly to be classified among the lower animals and referred to them as the Mycetozoa. He realized the difficulties in classification that arbitrarily separated the animal and vegetable kingdoms, for the Myxomycetes produced flagellate amoeboid swarm spores without walls. Whatever the implications of de Bary’s writings on the Myxomycetes (1858) for classification, he pointed out that in one stage they were seen as little more than formless, motile masses of the substance that Dujardin had called sarcode. This was the substance of the plasmodium, and protoplasm was the substance of the amoeboid cells as well. De Bary’s work served as evidence to his contemporaries of the protoplasmic substratum of life.

Various of de Bary’s investigations demonstrated the sexuality of the fungi. He observed the conjugation of Spirogyra in 1858 and in 1861 described sexual reproduction Peronospora. He saw the necessity of observing life cycles in continuity and attempted to follow them in the living plant as far as possible. To this end he introduced methods for sowing spores and watching them as they developed.

De Bary’s first writing on the fungus that caused the potato blight appeared in 1861, and over the next fifteen or more years he engaged in research on the Peronosporeae, which included the potato fungus, then known as Peronospora infestans His researches on this fungus, on Cystopus (Albugo) and on the Uredinales (the rusts) led him to significant conclusions, which he related in answer to a prize question that the Académie des Sciences proposed in 1861. They were published in the paper “Recherches sur le développement de quelques champignons parasites,” in the Annales des sciences naturelles in 1863. His direct observations of these parasites of living plants had involved de Bary in the question of spontaneous generation. He had seen numerous methods by which these organisms penetrated healthy plants and developed within their tissues. They had always originated, however, from germs of the same parasitic species, never from the substance of the host plant and never through any predisposition of the host to disease; in fact, they prospered all the more, he claimed, the healthier the plant they invaded.

De Bary outlined the course of the potato blight. He had successfully sown spores of Peronospora infestans on healthy potato leaves, and he described the penetration of the leaf and the subsequent growth of the mycelium that affected the tissues, the ensuing formation of the conidia, and the appearance of the characteristic black spots of the potato blight. He had also sown Peronospora on potato stalks and tubers, and even had watered conidia into the soil to infect healthy tubers. He believed that the mycelium could survive the winter in the tubers. Certainly there was no spontaneous generation. Some observers might conclude that Peronospora arose from within the potato plant because traces of penetration had disappeared, but de Bary maintained that undoubtedly the contagion was due to the numerous germs of parasites and the exterior conditions that favored their invasion of the host plants.

Some years later the Royal Agricultural Society of England asked de Bary to continue his investigations of the potato blight. In 1876 he reported that although he had not yet been able to find the sexual organs of the fungus, which he now named Phytophthora infestans, he could account for the known facts of the potato blight, since he could produce the disease in healthy plants by inoculation and reconstruct the fungus’ life cycle by experiment and by analogy with others of the Peronosporeae.

To de Bary’s knowledge, the potato fungus had but a single host, but in his investigations Puccinia graminis, the rust affecting wheat and other grains, he found the phenomenon of heteroecism, for this parasite required two unrelated hosts in order to complete its development. The destruction caused by this rust had been familiar since ancient times, and it was established, but on empirical grounds only, that the occurrence and spread of the rust in wheat fields was somehow related to the presence nearby of the common barberry, Berberis vulgaris; in fact, the eradication of barberry plants had long been practiced, and in some instances even required by law, as a preventive measure.

De Bary’s observations and experiments extended the investigations of the Tulasne brothers, who had shown the pleomorphism of the Uredinales. He knew that Puccinia graminis, the rust of wheat, rye, and other grasses, developed reddish summer spores, the urediospores, and dark winter spores, which he called “trlrutodpotrd,” Carefully he distinguished the series of reproductive organs that appeared, and he proceeded to actual inoculation experiments. In 1865 de Bary wrote that he had sown sporidia from the winter spores of the wheat rust on the leaves of the common barberry. The sporidia had germinated, and through successive stages had led to the formation of the yellow aecium spores, a familiar sight on the barberry. The aeciospores, and the rest of the reproductive structures of the rust, could reach further development only on cereal plants. In his experiments de Bary had difficulty in obtaining germination of the aecidio-spores directly on cereal plants, but in 1866 he could report that he had succeeded in sowing aecidiospores on moisture-retaining slides, then inoculating the leaves of seedling rye plants. In time the reddish summer spores appeared on the leaves, and although his specimens wilted before the formation of the winter-hardy teleutospores, this succession was well known in fields subject to the ravages of the rust. The sporidia from the winter spores germinated, but only upon the barberry; the cycle was then complete.

De Bary thus demonstrated that Puccinia graminis required different hosts during the different stages of its development and termed such species heteroecious, as opposed to autoecious species, which passed through their entire development requiring but one host.

His researches clarified other complex relationships as well. He described the formation of the lichen through the associated vegetative processes of the fungus and alga. There were various modes by which parasites lived and affected their hosts; de Bary traced the stages through which they grew and reproduced and the adaptations that enabled them to survive drought and winter. He was careful with his inoculations and cultures, and as he remarked in a popular lecture, Umber Schimmel und Here (Berlin, 1869), the organisms termed molds, yeasts, and fungi, despite their peculiarities, exhibited structures and phenomena that were fundamentally those common to plants. To de Bary they were like other plants, only smaller, and were derived ultimately from forms like themselves.

De Bary coined the word “symbiosis” in 1879 in his monograph Die Erscheinung der Symbiose (Strasbourg, 1879), using it to mean “the living together of unlike organisms,” as a collective term to describe a broad range of relationships. Some organisms, he wrote, existed in conditions of “mutualism” there was lichenism; there were parasites that could live apart from their hosts at certain periods; there were other parasites completely dependent upon their hosts; between these associations there were infinite gradations.

In his major works on morphology, published between 1866 and 1884, de Bary included the latest botanical researches and the results of his own investigations. His books contain classic descriptions and illustrations, and they were signal contributions to classification and to the systematization of botanical knowledge, establishing mycology as a science.

De Bary’s methods and concepts had important applications in the growing field of bacteriology. His lectures on bacteria, Vorlesungen über Bacterien, which he published in 1885, presented what was then known of the bacteria. He wrote more than 100 papers on subjects ranging from apogamy in ferns to insect-killing plants. Meanwhile, as a teacher, he continued to encourage his students in their own researches and to accompany them on botanical excursions in the environs of Strasbourg.

At an early period de Bary’s views on the question of spontaneous generation were in agreement with those of Pasteur. He was therefore critical of culture procedures and aware of the ease with which “unbidden guests” might intrude into apparatus. His descriptive and experimental work had broad implications for bacteriology as well as for botany, and he was one of the most influential of the nineteenth-century botanists, both in his own time and in ours.

BIBLIOGRAPHY

I. Original Works. De Bary’s extensive writings range from comprehensive reference works to numerous contributions to the botanical periodicals. A more complete listing of his publications can be found in the articles by Jost, Reess, and Solms-Laubach (see below). De Bary’s Morphologie und Physiologie der Pilze, Flechten und Myxomyceten (Leipzig, 1866) was the second volume of Wilhelm Hofmeister’s Handbuch der physiologischen Botanik. The second edition, Vergleichende Morphologie und Biologie der Pilze, Mycetozoen und Bacterien (Leipzig, 1884), in many respects a new work, appeared in an English translation by Henry E. F. Garnsey and Isaac Bayley Balfour as the Comparative Morphology and Biology of the Fungi, Mycetozoa and Bacteria (Oxford, 1887). His Vergleichende Anatomie der Vegetationsorgane der Phanerogamen und Farne (Leipzig, 1877) constituted the third volume of Hofmeister’s handbook; its English edition, F. O. Bower and D. H. Scott, trans., was the Comparative Anatomy of the Vegetative Organs of the Phanerogams and Ferns (Oxford, 1884). The second edition of the Vorlesungenüber Bacterien (Leipzig, 1885, 1887) was translated and revised by Garnsey and Balfour as Lectures on Bacteria (Oxford, 1887). The early monograph on the rusts and smuts was Untersuchungen über die Brandpilze und die durch sie verursachten Krankheiten der Pflanzen (Berlin, 1853.

The many subjects of de Bary’s studies are only indicated by the papers he wrote, including: “Ueber die Myxomyceten,” in Botanische Zeitung, 16 (1858), 357–358, 361–364, 365–369; “Ueber die Geschlechtsorgane von Peronospora,” ibid., 19 (1861), 89–91; “Recherches sur le developpement de quelques champignons parasites,” in Annales des sciences naturelles, botanique, 4th ser., 20 (1863). 5–148; “Neue Untersuchungen uber die Uredineen, in besonders die Entwicklung der Puccinia graminis and den Zusammen–hang derselben mit Aecidium Berheridis,” in Monatsbericht der Koniglicher Preussischen Akademie der Wissenschaften zu Berlin (1865), 15–50, and “Neue Untersuchungen uber Uredineen,” ibid. (1866), 205–216; and “Researches Into the Nature of the Potato Fungus–Phytophthora infestans,” in Journal of the Royal Agricultural Society of England,. 2nd ser., 12 (1876), 239–269.

II. Secondary Literature. The place of de Bary in the history of mycology and the relation of his studies of the life histories of fungi to the problems and question of his day are discussed by E. C. Large in The Advance of the Fungi (New York, 1940, 1962); and aspects of his work by G. W. Martin in “The Contribution of de Bary to Our Knowledge of the Myxomycetes,” in Proceedings of the Iowa Academy of Science, 65 (1958), 122–127: and W. B. McDougall in “The Classification of Symbiotic Phenomena,” in Plant World, 21 (1918), 250–256. A contemporary assessment of de Bary’s contributions is that of Ferdinand Cohn, himself a noted botanist whose researches were basic to the science of bacteriology, in his obituary notice,” Anton de Bary, “in Deutsche medicinische Wochenschrift, 14 (1888), 98–99, 118–119. Further sources of biographical information are Ernst Almquist. Grosse Biologen (Munich, 1931), pp. 57–60; Ludwig jost, “Zum hundertsten Geburtstag Anton de Barys, “in Zeitschrift für Botanik, 24 (1930), 1–74; M. Reess, “Anton de Bary,” in Berichte der Deutschen botanischer Gesellschaft, 6 (1888), viii-xxvi; H. Grafzu Solms-Laubach, “Anton de Bary,” in Botanische Zeitung, 47 (1889), 33–49; Marshall Ward, “Anton de Bary, “in Nature, 37 (1888), 297–299; K. Wilhelm, “Anton de Bary,” in Botanisches Centralblatt, 34 (1888), 93–94, 156–159, 191–192, 221–224, 252–256; and C. Wunschmann, “Heinrich Anton de Bary,” in Allgemeine deutsche Biographie, XLVI (Leipzig, 1902), 225–228.

Gloria Robinson