His professional success did not lead him aside from his favourite studies; and he kept his eye steadily on the great object of his ambition, the botanical chair at Upsal. In 1741 he was appointed medical professor. He soon entered into an agreement with Professor Rosen to allow him to perform the duties of the botanical chair, while his colleague lectured on physiology and other subjects. Before entering on the duties of his professorship, he pronounced a Latin oration before the University, “On the Necessity of Travelling in our own Country.”
Linnæus was now placed in the situation which of all things he had most coveted. The academical garden was soon laid out on a new plan. When he was appointed professor, it did not contain above fifty exotic plants. In 1748, six years afterwards, he published a catalogue, from which it appears that he had introduced eleven hundred; besides the vegetable productions of Sweden itself.
He now applied to all his correspondents for plants; and, writing to Albert Haller, he says, “Formerly I had plants, but no money; and now, of what use is my money without plants?” His exertions so much extended the fame of the University, that the number of students considerably increased, particularly during the time he held the office of rector. They came from Russia, Norway, Denmark, Great Britain, Holland, Germany, Switzerland, and even from America. He made summer excursions attended by his pupils, often to the number of two hundred. When some rare or remarkable plant, or other natural curiosity, was found, a signal was given by a horn, at which the whole party assembled round their leader.
Linnæus published his “Amœnitates Academicæ,” “Philosophia Botanica,” and “Species Plantarum,” respectively in 1749, 1751, and 1753. Of these, the first is a collection of treatises on various subjects; the second is the foundation of the Linnæan system of botany, and from it most of our popular introductions have been compiled; the third is termed, by Haller, “Maximum opus, et æternum!” In this work he first employed trivial words as specific names: thus, the species of every genus is designated by a single epithet, expressive of some obvious character, and the tiresome plan of quoting an entire description to distinguish the species was abandoned. His fame had now rapidly increased, and his scientific connexions and correspondence with foreign countries had become very extensive.
In 1753 he was elected a Fellow of the Royal Society of London; and in the same year his sovereign, Gustavus III., bestowed upon him a most flattering mark of his regard, by creating him a Knight of the Polar Star. This order had never before been conferred on any literary character; nor had any person below the rank of a nobleman been honoured with it. Foreign countries were not backward in testifying their sense of his merits; he was a member of the Royal Academy of Sciences of Paris, of St. Petersburgh, and of Berlin; and there was hardly a learned body in Europe but was anxious to enrol his name among their numbers. The most flattering compliment which he received was from the King of Spain, who invited him to settle at Madrid, with the offer of an annual pension for life of 2000 pistoles, letters of nobility, and the free exercise of his own religion. He, however, did not accept of this offer, but answered, that if he had any merit, his services were due to his own country.
The University of Upsal had now become an object of curiosity: strangers were attracted there, and prolonged their stay, solely with the view of becoming acquainted with Linnæus. Among other visitors, the Earl of Macartney, when he was English Minister at St. Petersburgh, went from that city on purpose to visit him. His writings were soon appreciated in foreign countries, and his system was first publicly taught in our own by Professor Martyn, in the University of Cambridge. His pupils spread themselves over the globe; they carried everywhere with them the spirit of their master, and diffused the love of natural history. When Captain Cook’s first voyage was undertaken, one of Linnæus’s most celebrated pupils, Dr. Solander, accompanied Mr. Banks in the capacity of naturalist. It was not, however, from his pupils alone that Linnæus received information; in every part of the world persons were found anxious to forward specimens to him, and his collections thus became unrivalled.
The introduction of the Linnæan system was attended with such great change, especially of nomenclature, that it experienced considerable opposition from the older naturalists; and the biographers of Linnæus have recorded several literary feuds with distinguished contemporaries, and especially with Albert Haller, a genius of equal merit with himself.
The latter years of Linnæus were spent in a state of ease, affluence, and honour, very different from the poverty and obscurity of his early life. He was one of those great men, who have shown by example how much the genius and activity of an individual are capable of accomplishing. He was the reformer of botany, and perhaps the greatest promoter of natural history that ever lived; and so much has never been done for that science, in so short a space of time, as at the period he flourished, and immediately after.
In 1773 the reigning King of Sweden appointed him, in conjunction with others, to make a new translation of the Bible into the Swedish language. In the month of May, 1774, whilst lecturing in the Botanical Garden, he was attacked by apoplexy, the debilitating effects of which obliged him to relinquish the more active parts of his professional duties, and to close his literary career. In 1776 a second apoplectic fit paralysed his right side and impaired his mental powers. Even in this painful and miserable state the study of nature remained his greatest pleasure, and he was constantly carried into his museum to survey the treasures there accumulated. He died January 10, 1778, in the seventy-first year of his age.
On his death a general mourning took place at Upsal. A medal was struck upon the occasion, and a monument erected to his memory in the cathedral church of Upsal. The King of Sweden himself pronounced a panegyric on his distinguished subject before the Royal Academy of Sweden.