Linnæus was endowed with too sound a judgment, with a tact too exquisite, not to feel the defects of this artificial mode of classification. He detected by the force of his genius the existence of vegetable groups superior to genera, and connected them by a large number of characteristics. He called this group a _natural order_, and it has since his time been called a “natural family.” He also tried to distribute plants after a natural classification--that is to say, into families. After the death, and during the life, of Linnæus, botanists endeavored to discover upon what principle he had founded his _natural orders_--that is to say, they sought to find the key to the hidden principle of his orders; but no one has succeeded. Linnæus himself does not appear to have had very fixed views on the subject. He created his orders by a sort of instinct which belongs only to the man of genius; by that kind of semi-divination which the man of learning acquires who possesses vast and profound knowledge of the objects which he passes his life in observing. In a letter we find the following passage: “You ask me for the characters of my orders. My dear Giseke, I assure you that I know not how to give them.” Magnol, professor of botany to the School of Medicine, in his work entitled _Prodromus Historiæ Generalis Plantarum_ (1689), is the first author who uses the happy term “family” to designate natural groups of vegetable genera. M. Flourens speaks of the preface to this little book of a hundred pages as calculated to immortalize the author, as in it was first solved a very difficult problem. The following lines are taken from this much-admired preface: “Having examined the methods most in use,” says Magnol, “and found that of Morison insufficient and very defective, and that of Ray much too difficult, I think I can perceive in plants a certain affinity between them, so that they might be ranged in divers _families_, as we class animals. This apparent analogy between animals and plants has induced me to arrange them in certain families, and, as it appeared to me impossible to draw the characters of these families from the single organ of fructification, I have selected principally the most noted characteristics I have met with, such as the root, the stem, the flower, the seeds. There is also found among plants _a certain similitude_, a certain affinity, as it were, which does not exist in any of the parts considered separately, but only as a whole. I have no doubt, for instance, but that the characters of families might be taken from the first leaf of the germ as it issued from the seed. I have followed the order that the parts of plants follow in which are found the principal and distinctive characters of families, but without limiting myself to any one single part, for I have often considered many of them together.”