The idea which Linnæus made use of was not original with him, for it was hinted at by more than one old Greek, and had lain dormant in the minds of naturalists for centuries, but Linnæus was the first to think of using it as a basis for a system of classification, and it must thus be forever associated with his name.

This system is called the artificial system, because it merely furnished a convenient method of finding the name and place of a plant, without regard to its relationship.

The natural system, which is based upon the relationship of one family of plants with another, in time superseded the Linnæus system, which owes its chief interest now to the fact that it was the first classification which made it possible to reduce the study of botany to a science, and that its establishment led to the development of the natural system, which Linnæus himself declared to be the only true way of classifying, and which his system only embraced in part.

After his appointment as professor at other honors rapidly followed. The next year he was commissioned by the Royal Academy of Sciences to travel through Lapland and examine its natural curiosities and productions, and this trip was a source of great pleasure to him though travelling was often dangerous in those remote regions, where rocks and marshes obstructed the way, and roads were almost unknown. It was while on this trip that he found a little unknown plant growing in shady places which he immortalized by giving it his own name, the Linnæa borealis, and which, he said, typified his own "neglected fate and early maturity."

The journey was a success, and raised him still higher in the estimation of Upsala, but his honors could not shield him from the jealousy of enemies who prevented his obtaining the position at the university that he expected to receive, and, disappointed in this, Linnæus left Upsala and undertook a journey into Norway under a commission from the Governor of Dalecarlia; and with this trip he began those extensive travels which lasted through so many years and in which he gained the experience that enabled him to go on with his work and add more and more to his fame.

From Dalecarlia he proceeded to Holland, where he wished to obtain his degree, going by the way of Hamburg, whose honest burghers he insulted by revealing the fact that their wonderful hydra, or seven-headed serpent, was nothing more than a clever fraud, with its seven heads all made of the jaw-bones of weasels, and this made him so unpopular that some friends actually advised him to shorten his stay in the city.

He took his degree as Doctor of Medicine at Harderwyk (1735), and immediately after went to Leyden, where he formed the acquaintance of the celebrated naturalist Gronovius, who was so astonished when Linnæus showed him his Systema Naturæ that he offered to publish it at his own expense.

The publication of this work immediately brought Linnæus to the notice of all the eminent naturalists of Europe, and procured for him great attention wherever he appeared; and during the three years he spent in Holland, France, and England he received the most distinguished favors.

All this, however, could not prevent a longing for home, whither he returned in 1738, and four years after was appointed Professor of Botany at Upsala, a position he had long desired.

And now life, at last, seemed only pleasant to him. Occupying the proud position of the first naturalist in Europe, and with means at his hand to command whatever resources he desired, he devoted his time more diligently than ever to study, and gained new honors year by year. The number of students in the university increased from five hundred to fifteen hundred, all attracted by the fame of Linnæus, and the collection of plants in the botanical gardens soon became unrivalled.

Rare specimens were sent to him from the most distant places, and his pupils were soon scattered all over the globe, carrying his name and fame with them, and thinking themselves well repaid for all their trouble if they were able to bring some new or rare plant to their beloved master. Many important discoveries were made at this time by Linnæus, not the least interesting being that of the sleep of flowers, which was first brought to his notice by the closing of the petals of a lotos in the evening.

From this circumstance he formed the theory, and proved that flowers have regular periods of sleep, and he made a little calendar in which the hours of the day were marked off by the closing of the different blossoms.

In these congenial pursuits time passed pleasantly enough, and Linnæus almost forgot the hardships and struggles of his early youth. Sweden, ever ready to do him honor, offered him one mark of distinction after another, until there seemed nothing left to offer. In 1761 the king made him a noble, and the family was thenceforth called Von Linnæus, an honor little dreamed of by its peasant-founder. And thus, with the years full of content, life went happily on, and when old age came to Linnæus he could reflect on years that had been well spent and full of good to his fellow-men.

During the last years of his life he suffered much from disease and mental weakness, but still kept his serene and cheerful spirit, and never lost his keen interest in his beloved studies.

And when death came to him at last one day as he lay quietly sleeping, it seemed but as the folding of the perfect flower which closes its petals when its time of expansion is over, and becomes a fragrant memory, full of a sweetness and grace as enduring as the immortal beauty of which it was a part.