JUSSIEU, ANTOINE LAURENT DE, an eminent French botanist, was born at Lyon in 1748, and arrived at Paris in 1765 for the purpose of completing his education as a medical practitioner. He was then placed under the care of his uncle, Bernard de Jussieu, at that time one of the demonstrators of botany in the Jardin du Rai, at man possessing a profound knowledge of plants, and who probably gave his nepliew.the filet interest in the science which he subsequently illustrated with so much success. In the year 1770, his medical studies having been completed, ho took the degree of Doctor of Medicine, on which occasion the title of his thesis was, 'An mconomiam vitalem inter et vegetalem analogic; a subject which sufficiently marks the turn his studies had already taken. In the same year he was nomi nated botanical demonstrator in the Jardin du Roi, as a substitute for Lemonnier, whose duties as chief physician to the king prevented his executing that office in person. Thus at the early age of twenty two years Jussieu found himself under the necessity of undertaking the duty of teaching students the essential characters of the plants cultivated in the Paris Garden—a task for which experience in details and practical knowledge were required, rather than that general acquaintance with botany which a young man just released from his medical curriculum might be expected to possess. This obliged him to study one day the subjects to be demonstrated the next, and to occupy himself incessantly with acquiring a correct practical acquaint ance with plants. At that time the collection of plants in the Janlin du Roi was arranged according to the method of Tournefort ; but shortly afterwards it became necessary to rearrange it. Of this oppor tunity Jussieu took advantage ; he drew up a memoir upon a new teethed of arrangement, which w as read before the Academy of Sciences, and afterwards carried into effect in the garden. The idea of this method was undoubtedly taken from a classification of the plants in the Royal Garden of Trianon, executed under the direction of his uncle; but it was different in much of the details, and was prepared without consultation with Bernard do Jussieu, who in fact was at that time old, nearly blind, ill, and incapable of taking part in any mental exertion. Previously to this, young De Juseieu had studied
the natural order 1?antinculacece with so much attention, that he made it the subject of a communication to the Academy of Sciences, in whose ' Transactions' it was printed. In after-years he used to say that it was the composition of this memoir which had opened his eyes to the real principles of botanical classification and made him a botanist. It is here that is found the first distinct trace of those clear ideas concerning the relative importance and subordination of characters which the author subsequently applied to the whole veget able kingdom. In reality there is no natural order of plants altogether so well suited for this purpose as that which happened to be selected.
From this time, that is, from the year 1774 to 1769, De Juesien was constantly occupied in demonstrating to his class of botany; and as his new method was thus brought perpetually before hint, with all its advantages and disadvantages in practice, he was able to alter and improve it yearly. 'The distinctions of genera, their mutual relation, the natural sequence of his orders, and in addition all that was Ivritte by other botanists during this period, became so familiar to him, that his son records his having actually commenced his great work, the ' Genera Plantarnm,' in 1766, without having prepared more then the commencement of the manuscript ; and he adds that he was seldom, during the printing, above two sheets in advance of the compositors ; a very remarkable circumstance, if the extreme attention to clearness and arrangement conspicuous iu this work are borne in mind. It is however always to be remembered that in those days botany was very different to what it now is, several thousand genera being now included in general works which were unknown to Juseieu.