When about to depart from Leyden, Linnæus went to take leave of Boerhaave. The interview, which, however melancholy, was very flattering, is thus related by him: "That great man, who was affected with a dropsy of the chest which forced him to keep himself always sitting in his bed to prevent suffocation, would not receive visiters, but admitted me to bid him farewell. Summoning the little strength that remained in him, he raised my hand to his lips, and said: 'I have finished my career, and all that I have been permitted to do I have done; may God preserve you, who have yet a greater task to perform! What the learned world expected from me it has obtained; but it expects much more from you, my dear son. Farewell, farewell, my dear Linnæus!'"
Having gone with Cliffort to Amsterdam, and afterwards to Leyden, he visited among others his friend Van Royen, professor of botany, who having made proposals of marriage to Miss Boerhaave, the sole heiress of the great physician, had been rejected, and therefore vowed hostility to the family. The botanic garden there had been arranged and described agreeably to Boerhaave's method; but the other now resolved to alter the disposition, and adopt the system of Linnæus. He accordingly offered him a salary of eight hundred florins, if he would live with him, and assist in the execution of this scheme. Influenced by respect for his deceased friend, he would not countenance the alteration, although he devised a plan by which neither his benefactor nor himself should receive the honour. He remained with Van Royen, classed the plants after a principle of his own invention, and drew up a catalogue of them, which was published in the name of that teacher.
The next work which he printed was produced by the genius and industry of Artedi. When he resided at Leyden, previous to his going to Hartecamp, he had the pleasure of meeting this friend of his youth, who had left Sweden in 1734, and gone to England to prosecute his scientific labours. From thence he went to Holland for the purpose of obtaining his degree, which he was unable to accomplish on account of his extreme poverty. Linnæus recommended him to Seba, an apothecary at Amsterdam, and author of a large work on natural history, who received him as his assistant. But soon after, returning home in a dark night, he fell into a canal and was drowned. His countryman had the melancholy satisfaction of depositing his remains in the grave; and having induced Cliffort to purchase his manuscripts, which were detained for debt, he arranged and committed them to the press. This tract, in his opinion, was the best that had appeared on the subject of fishes. He also published his own Classes Plantarum, in which he presented a general view of all the botanical systems that had been previously proposed.
His ambition was now on the point of being attained. Not only were his works received with approbation, but his principles had been adopted by several teachers. He had also formed connexions in Holland which promised to be of the greatest advantage to him; and the Dutch, desirous of securing his services, proposed that he should make a botanical voyage to the Cape of Good Hope, with the promise of a professorship on his return.
But Linnæus about this time was seized with an ardent desire to revisit his native country, and fell into a state of extreme depression of spirits, succeeded by a violent fever, which lasted upwards of six weeks. His excessive application to study may be considered as the source of his complaints; and perhaps to this may be added his disquietude concerning the daughter of Moræus. But it does not, however, appear that his love for Elizabeth was equal to that for botany or even for his own renown; for though the stated period had elapsed, he still resolved to make a journey to Paris before returning to the place of his birth.
He reached that capital in the beginning of May 1738, and was kindly received by the two Jussieus, one of whom was the successor of Tournefort.—It is related by M. Fée, that on his arrival he went first to the Garden of Plants, where Bernard de Jussieu was describing some exotics in Latin. There was one which the demonstrator had not yet determined, and which seemed to puzzle him. The Swede looked on in silence, but, observing the hesitation of the learned professor, cried out,—"Hæc planta faciem Americanam habet,—It has the appearance of an American plant." Jussieu, surprised, turned about quickly and exclaimed,—"You are Linnæus."—"I am, sir," was the reply. The lecture was stopped, and Bernard gave the learned stranger an affectionate welcome. Through the kind offices of these amiable men and excellent botanists, he was introduced to many of the literati of Paris, and obtained access to the libraries, collections of natural objects, and public institutions. The French, however, were by no means disposed to adopt his views: "He is a young enthusiast," they said, "who confounds all, and whose only merit consists in having reduced botany to a state of anarchy." He was, notwithstanding, admitted a corresponding member of the Académie des Sciences. He then visited Versailles, accompanied by his two friends, who defrayed all his expenses, and showed him the public libraries, the museums, and the most celebrated private collections, especially that of Reaumur. "Linnæus," says he, in his autograph memoirs, "was now desirous of returning to Sweden without further delay, for time seemed to him too valuable to allow him to engage in studying the manners and language of the French. He never had a genius for languages, nor could he ever render himself familiar with the English, French, German, or even the Lapland tongues. He felt the same difficulties with respect to Dutch, although he had resided three years in Holland. This, however, fortunately did not prevent him from making himself sufficiently understood. After seeing all the curiosities at Paris, he went to Rouen in the dog-days. There he embarked for the Cattegat, with a favourable wind, and after crossing the Sound landed at Helsingburg. He immediately visited his old father at Stenbrohult, rested there a few days, and set out for Fahlun. After being formally betrothed to his bride, he proceeded to Stockholm, where he arrived in September."
He had left his native country in April 1734, and returned in the autumn of 1738, having been absent three years and a half. In the course of this period, he visited Holland, England, and France, formed acquaintance with many eminent naturalists, obtained his medical degree, published numerous works on botany, and extended his fame over all Europe.
With respect to the improvements which he made in that branch of natural history, it is unnecessary here to enter into any detail, as it is proposed to speak particularly of them in a subsequent volume. It may be sufficient to remark, that there had not previously been any good arrangement of plants; that the principles of the science had not been laid down in a satisfactory manner; that the nomenclature was barbarous and unsuitable; the mode of distinguishing species rude and inefficient; and that, in short, the works on this subject were little better than a chaos of names and unintelligible descriptions. Some writers maintain, indeed, that he did more harm than good, when he became the legislator of botany. But their opinion can deceive those only who, too idle or too weak to judge for themselves, adopt the sentiments of their teachers with a deference unworthy of the student of nature.