JUSSIEU (BERNARD DE,) younger brother of the preceding, and like him a Physician, and a member of the Académie des Sciences, was still more devoted to the philosophical as well as practical study of botany, and ranks among the greatest names in that science, as having first attempted to form a system, according to the natural affinities of plants. He was born at Lyons in 1699, and appears to have accompanied, or followed, his brother to Paris, where he occupied, under him, the place of botanical demonstrator, in the Jardin du Roi, and at length succeeded him as Professor of Botany. If his communications to the Academy were less numerous than those of his brother, they were of a rather superior character. In one of them, published in the Mémoires of that body for 1742, he enters on the subject, then scarcely touched by any person, of the animal nature of certain marine productions, previously taken for plants; and we perceive, in his inquiries, dawns of that meridian light, which our countryman Ellis afterwards threw on these curious tribes. On other occasions he explained the flowers of the Littorella, and, with much acuteness, the more obscure fructification of the Pilularia. He wrote, in conjunction with the learned Comte de Caylus, on the Papyrus, and he gave an improved edition of Tournefort's History of the Plants about Paris, in 1725.
Linnaeus became personally acquainted with this ingenious man at Paris, in 1738, and maintained, for some years, an intimate correspondence with him. They could not be long in each other's company without discussing the natural affinities of plants, a study which seems to have been much advanced, if not first excited, in the mind of Linnaeus, by his correspondence with Haller. Bernard de Jussieu had, about the same time, by his own contemplations, probably, been led to consider it; for the system of Tournefort, in which he was educated, is too artificial in principle to have given him any such ideas. In its execution, indeed, that great author is led, by his own good sense, into some natural and philosophical views, in spite of his system; and these may possibly have caught the attention of Jussieu. However this may be, mutual satisfaction, and reciprocal instruction, could not but flow from the converse of Bernard de Jussieu and Linnaeus. They traced out together the characters and the limits of various natural assemblages, or orders. Every day produced, and every letter communicated, some new discovery. But as the multifarious hordes of the north appear originally to have used one common tongue, which, after they were dispersed, divided, and cultivated,
when it came to be written, assumed the form of various distinct languages; so these two botanical philosophers, when their more intimate intercourse had ceased, pursued different paths, and went far towards different conclusions. Linnaeus, after throwing the whole vegetable creation, more or less completely, into natural groups, became more and more persuaded, that it was not only impracticable to connect them by one synoptic clue, or system, but that not one of his assemblages, or orders, was capable of precise and unexceptionable definition. On the other hand, Bernard de Jussieu, to the last, aimed at a general scheme of classification, though he accomplished little more than throwing his several orders into larger assemblages, and disposing the whole, as indeed Linnaeus himself has done, in one series, according to their relationship to each other. The French botanist is recorded to have spoken with great diffidence of his own performance, and has written nothing of a general classification. But he often gave hints, in lectures or conversation, by which others perhaps have profited. This appears from the preface to the Genera Plantarum of his distinguished nephew, Antoine Laurent de Jussieu, the present Botanical Professor at Paris, who, following up the ideas of his uncle, and sacrificing something to technical convenience, at the expense of nature, has contrived to exhibit a tolerably natural system, founded on methodical principles.
It would be to little purpose to discuss, at the present day, the claims of Linnaeus or of Bernard de Jussieu to originality in the study of natural orders. Professor De Candolle has justly asserted, that they had the same object in view, and adopted, in the main, the same principles. B. de Jussieu, in a letter, dated February 15, 1742, congratulating Linnaeus on his appointment to the botanical chair at Upsal, says, "Floræ devotus omnino poteris viam quam monstrasti facilem ampliùs aperire, naturalemque methodum tandem perficere, quam desiderant et expectant botanophili omnes." In a subsequent letter of May 7, 1746, he tells his Swedish friend, "Scio quantum emolumentum receperint qui secundum tua principia student; memet experientia docuit." This is enough to settle the question, though great allowance is, perhaps, due to the modesty of Jussieu, who was less disposed to honour himself than his friend.
His biographer, the celebrated Marquis de Condorcet, records his singularly amiable and unaffected manners. These, during his occupation of arranging, according to natural classes, the garden of Trianon, attracted the notice and esteem of his sovereign, Louis XV. to whom any unsophisticated character, or object, could not but form an agreeable relaxation from the routine of a court. Jussieu obtained plants and seeds to be sent to his friend in the king's name. He pursued his innocent and useful studies till his death, which happened in 1777, in his 79th year.
A compendious view of his nephew's system, and a comparison of their Natural Orders with those of Linnaeus, may be seen under the article BOTANY, in the second volume of this Supplement. (J. J.)