Page:Popular Science Monthly Volume 71.djvu/509

Rh briefly the earlier history of the ideas involved in each of these three reforms.

First, then, concerning classification. Linnæus's great precursors in this field were Cesalpino, Ray and Tournefort. Cesalpino was a sixteenth-century enthusiast of the revival of the Peripatetic philosophy; and it was largely the influence of a fresh study of Aristotle's logic and metaphysics which led him to condemn all the then customary ways of classifying and naming plants—by their medicinal or other practical properties, the localities in which they are found, and the like—as being based upon mere "accidentia" and to insist upon the necessity of an orderly arrangement by genera and species founded upon the presence of common visible characters. In his selection of the characters by reference to which the primary division into genera is to be made, he is guided by considerations drawn from the Peripatetic metaphysics. The essential character of any "substance" consists in its "end" or "function" (opus). The distinctive function of the vegetative soul is twofold, nutrition and "the generating of its own like"; the latter is the higher, and it also presents more numerous and sensible points of variation in different plants. It follows that plants should be divided into genera according to the differences in form and arrangement of their "fruit-producing" organs (ex modo fructificandi, ex propriis quae fructificationis gratia data sunt). "With this as a starting-point, Cesalpino proceeds to a series of successive divisions in which 840 species find place. Ray's contributions to taxonomy had less success and influence than those of Cesalpino and of Tournefort, and are therefore historically less significant; but concerning their intrinsic merit it is worth while quoting the recently expressed opinion of a living botanist of high authority, who places Ray as a taxonomist above Linnæus himself. It was the English naturalist, says M. Bonnier, who must be regarded as "the true founder of the natural method"; "he it was who first enunciated the essential principles on which the classification of plants ought to be founded, who made clear the difference between phanerogams and cryptogams, who discovered the distinction between monocotyledons and dicotyledons, who established in a rational manner the main divisions of the vegetable kingdom."