JUSSIEU, ANTOINE LAURENT DE

JUSSIEU, ANTOINE LAURENT DE, the most illustrious member of a family which has given several great names to science and was long known as the dynastie botanique of France, was born at Lyon, April 12, 1748. At the age of seventeen he left his native town to study medicine in Paris. He took up his abode with his uncle Bernard de Jussieu, one of the lecturers on botany in the Jardin du Roi, and a man of immense scientific learning and skill. The teaching and example of this relative first gave the young student a taste for the science which he may be said in a great measure to have created, or at least re-modelled. He did not, however, wholly abandon medicine; but the thesis which he defended on taking his degree in 1770—"An Oeconomum Animalem inter et Vegetalem Analogia"—indicates

clearly enough the bent that his thoughts and studies had already taken. In this same year he was made professor of botany in the Jardin du Roi, in room of Lemonnier, whose duties as first physician to the king prevented him from lecturing regularly in person. This rapid and sudden promotion took him by surprise. He was only twenty-two years of age, and his knowledge was so far from being adequate to the duties of his chair, that he had to prepare carefully the evening before the prelections of the following day. His indefatigable zeal and industry soon brought him abreast of the science as then taught; and his Memoir on the family of the Ranunculaceæ procured his admission into the Academy of Sciences, and was incorporated in the Transactions of that body. In this memoir one sees the germs of that system of classification according to characters which he afterwards extended and applied to the whole vegetable kingdom. To illustrate the new method he could not have fixed upon a more safe or convenient order than that which he selected; and he used to say in after life that it was while engaged in preparing this memoir that he first felt himself truly a botanist. A wider field was presently opened up to him. The Jardin du Roi was at this time arranged according to the system of Tournefort. In 1774 the number of specimens had so greatly increased, that by the advice of Buffon it was determined to replant the garden. Jussieu profited by this occasion to send in to the authorities a scheme of his method, which was finally adopted. The general idea of it was undoubtedly borrowed from what was called the Catalogue of Trianon, which had been drawn up by his uncle Bernard. Many of the details, however, were so different, and the scheme itself was applied on such a large scale, that the credit of the whole fell to the younger Jussieu, especially as his uncle, now aged and infirm, and imbecile, had become a victim to the hereditary scourge of blindness. The new views were given to the world in a Memoir, entitled "Exposition d'un Nouvel Ordre de Plantes adopté dans la Démonstration du Jardin Royal," and embodied in the Transactions of the Academy of Sciences for 1774. Great as were the merits of the "Natural" system, Jussieu was himself well aware that as first evolved by him it was merely provisional. Accordingly, the next twelve years of his life, that is from 1775 to 1787, were entirely spent in testing it in his class lectures, and modifying it according to the new genera which were brought to him by travellers from every quarter of the globe. When at length, in 1778, he began to publish, so thoroughly had he matured his plan in its minutest details as well as its general outline, that he did not find it necessary to transcribe the whole work before consigning it to the press. Leaf by leaf his MS. was put in type as soon as it was written. The printing of the work lasted fifteen months, during all which time Jussieu, according to the testimony of his son, was never more than two sheets a-head of the compositors. The difficulty experienced in wringing either "copy" or "revises" out of his hands, and the elaborate care with which he corrected and often re-cast the proof-sheets, are dwelt upon by his biographers as sufficient evidence that he was really the author of his own work, and was not merely transcribing or translating into Latin his uncle's MS. notes, as was at one time alleged against him. Making due allowance for all this care, however, we are still surprised that the composition of the Genera Plantarum should have taken so long as it did. It only comprises some 2700 genera; and in the then state of botanical science could hardly have contained more. The botanical text-books of the present day contain from 9,000 to 10,000 genera. When at length the work appeared, it was at first very coldly received, and nowhere more so than in the author's native country. The artificial or sexual system of Linnaeus had been adopted in all the schools, and had taken root so firmly that it was impossible at once to eradicate it. The

Jussieu. hurricane of revolution was likewise sweeping over France, and men were too busy with politics to spare time for deciding between rival systems of botany. In England and Germany it began, though slowly, to find favour with the learned few; and when order was at length restored in France, its merits secured its adoption as the text-book in most of the scientific schools. It was not, however, till about the year 1820 that the Jussieuan system came to be recognised and publicly taught everywhere in England and America as well as on the Continent. The leading feature of this, as of every other natural system is, that it brings together all those plants which are allied in all essential points of structure, and takes into account the true affinities of plants on a comparison of all their organs. Assuming that as the lowest species which has no cotyledon in its embryo, that as next higher in the scale which has one, and that as highest of all which has two, Jussieu divided plants into the three primary groups of Acotyledones, Monocotyledones, and Dicotyledones, under which he included fifteen classes. Of these classes one is Acotyledonous, three are Monocotyledonous, and eleven Dicotyledonous. The three Monocotyledonous classes are distinguished by the position of the stamens, whether inserted on the thalamus (hypogynous), attached to the calyx (perigynous), or to the ovary (epigynous). Dicotyledonous plants are divided into Apetalous (monochlamydeous)—plants having a calyx only; Monopetalous (gamopetalous)—plants having united petals; Polypetalous—plants having separate petals; and Diclinous—plants which are unisexual and incomplete: the last constitutes the fifteenth class, while the other ten classes of Dicotyledons, included in the three other divisions, are determined chiefly by the position of the stamens and the corolla in relation to the ovary. Under these classes he included 100 orders. A tabular view of Jussieu's "Natural" system is given in art. BOTANY, part ii., chap. 2.

When the Revolution broke out, Jussieu, very much against his own wishes, was drawn into its vortex. In 1790 he was made a member of the municipality of Paris, and was entrusted with the supervision of the hospitals and charities,—an office which he held for two years. In 1793, when the Jardin du Roi was re-organised as the Museum of Natural History, Jussieu succeeded Daubenton as director and treasurer, and signalized his year of office by laying the foundation of what has since become one of the best, if not actually the best scientific library in Europe. From this time till 1820 he continued to enrich the Annales and Mémoires of the museum with contributions, bearing chiefly on the orders, genera, and species of his own system. After that year the infirmities of old age and blindness disabled him from keeping abreast with the progress of the science to which he had himself given the strongest impulse. In 1826 he resigned his chair at the museum in favour of his son Adrian, to whom he transmitted the virtues as well as the talents of his family. The next ten years of his life were spent in dictating a new edition of the Genera Plantarum, in which all the recent discoveries were to be embodied. But his strength was not equal to the task, and he never got beyond the introduction, which, however, is itself sufficient to show that to the last he retained that union of knowledge and philosophy which places him at the head of all the botanists of France. While lingering over this last effort of his mind he was carried off after a short illness, September 17, 1836, in the eighty-ninth year of his age. Jussieu's life, long as it was, and embracing the stormiest era of French history, was a happy and a peaceful one. His temper, less austere than that of his uncle, was singularly equable; and the fierce attacks that were often levelled against him never drew from him an angry or even a harsh retort. To the last he retained undiminished the affection of his family and the respect of his friends.