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.