In these circumstances it became necessary for him to think of some new occupation, and he seems not to have been long in forming a resolution to study medicine. His pecuniary circumstances, however, were so very limited, consisting of a pension of only 400 francs, that he was obliged in the mean time to employ himself as a clerk in the office of a banker in order to obtain the means of daily subsistence. The intervals he spent in study; and such were the buoyancy and activity of his mind, that even when his prospects were most discouraging, he never seems to have lost the expectation of rising to usefulness and distinction. He reverted with eagerness to the physical studies which he had commenced at college, and soon showed a preference for certain departments of natural history. He delighted to engage in controversial discussions on these subjects with his companions, and to indulge in speculations respecting the most abstruse points in physics and the phenomena of the natural world. It is not improbable that it was about this time, when the wide and varied fields of science were just beginning to open to his view, that he conceived some of those crude and fanciful notions which characterise so many of his theoretical views. It is less a matter of surprise that such ideas should suggest themselves, at the outset of his career, to one of his ardent temperament and lively imagination, than that he should have persisted in maintaining them when his knowledge was more extended and his judgment matured, although in the opinion of almost every other person their fallacy appeared demonstrable.
Botany and meteorology were the branches on which he first bestowed the greatest degree of attention. Even before he left the army, he had become attached to the former; and during his stay at Monaco, had examined the singular vegetation of that rocky country. During his illness, he was lodged, for the sake of economy, in an apartment at the top of a high house, from which the clouds formed almost the only spectacle; and to relieve the tedium of his long solitude, he was accustomed to watch their varying forms and aspects, and carefully to observe all the other atmospheric phenomena, indulging his fancy in forming conjectures about their nature and origin. This circumstance, he himself states, first inspired him with a desire to study meteorology; and we can perceive in these solitary meditations, one of the causes which tended to give their fanciful complexion to many of his subsequent speculations.
After continuing his physical studies with much ardour for several years, he at length appeared in the character of an author. His “French Flora, or a brief Description of all the Plants which grow naturally in France,” was published in 1778. The immediate occasion of this work was a desire to furnish his fellow-students with a system of arrangement which should lead with greater ease and certainty to the determination of plants than any then in use. For this purpose he adopted a modification of the binary or dichotomous method, the principle of which consists in arranging natural objects by their positive and negative characters, dividing and subdividing always by two, and allowing a choice only between two opposite characters. Although this plan is, of course, highly artificial, and ill calculated to throw light on the affinities and analogies of objects, yet it is much recommended by its extreme simplicity, which adapts it to the comprehension of those who have but little acquaintance with the technical and descriptive language of natural history. If judiciously applied, it affords an easy index to particular genera and species, and renders the subject at once accessible without any preparatory labour. Indeed, the principle on which it rests must to a certain extent be implied in every artificial system of arrangement.
This work soon acquired a considerable degree of popularity, not only by its intrinsic value, but from the seasonable time of its appearance. The study of botany, which had hitherto been confined almost exclusively to the members of the medical profession, was now becoming a popular and even fashionable pursuit; a distinction which it owed chiefly to the writings and example of J. J. Rousseau. Every work, therefore, calculated to facilitate the study, was likely to meet with a favourable reception among those who would probably have been repelled by dry technical details and rigorous scientific precision. Its publication had an important influence on Lamarck’s fortune and prospects. It secured for him the friendship and patronage of M. de Buffon, who was then in the height of his popularity, and possessed of much influence, not only from his rank, character, and celebrity, but also from his authority with the government. Even its want of a very philosophical and precise system was probably one of the circumstances that recommended it to Buffon’s attention, as it was thereby assimilated to his own writings, from which every thing of that nature was expressly excluded. Through his influence, an edition of the work was printed at the royal press, and its author introduced to the favourable notice of many of the leading savans of the day. He had soon an opportunity of turning his popularity to some profitable account, for a place happening to become vacant in the botanical department of the Academy of Sciences, Lamarck was presented with the appointment, in preference to others of older standing and much higher pretensions. He thus acquired a certain status among men of science, which encouraged him to prosecute the studies which he had so successfully begun, and at the same time afforded him the means of doing so in a more efficient manner.
Another important advantage was derived by Lamarck from the friendship of M. de Buffon. When the son of the latter had completed his studies, and was about to make a tour through various parts of Europe, Lamarck was invited to accompany him as tutor; and in order that he might enjoy greater privileges by appearing in a kind of official character, Buffon procured for him a commission as botanist to the king, for the purpose of visiting foreign gardens and cabinets, and opening a correspondence between them and similar establishments in Paris. In this double capacity he travelled through various countries in the year 1781 and 1782; visited Gleditsch at Berlin, Jacquin at Vienna, Murray at Gottingen, and many other celebrated naturalists; greatly extending his acquaintance, not only with botany, but with many other branches of natural history.
The extent and accuracy of his botanical knowledge was evinced by the important works in which he engaged shortly after his return, which have conferred on him a high reputation in this department. These consisted of voluminous contributions to the Encyclopédie Methodique, forming a Dictionary of Botany, and an extensive series of Illustrations of Genera. Of that portion of the Encyclopædia known by the former name, Lamarck wrote the whole of the two first volumes, and a part of the third, fourth, and fifth. The object of the work is to give a detailed history of plants, accompanied with descriptions, remarks on their synonymy, an account of their uses, and peculiarities of their structure. The Illustrations profess to afford “an exposition of the characters of all the plants established by botanists, arranged according to the sexual system of Linnæus, with figures displaying the characters of these genera, and a table of all the known species referable thereto, the description of which is found in the Botanical Dictionary of the Encyclopædia.” This laborious work contains no fewer than two thousand genera, illustrated by half that number of quarto plates, executed with great care, and generally representing one or two of the typical species, with