Pursuing his deductions, Cesalpino next shows, that the most important divisions, those of woody plants and herbs, must be maintained in accordance with the most important function of vegetation, that of drawing up the food through root and shoot; this division passed from the first and later on up to the time of Jung for an unassailable dogma, to which science simply had to conform. The second great function of plants is the producing their like, and this is effected by the parts of fructification. Though these parts are only found in the more perfect forms, yet the subdivisions (‘posteriora genera’) must be derived in both trees and herbs from likeness and unlikeness in the fructification. And thus Cesalpino was led, not by induction but by the deductive path of pure Aristotelian philosophy, to the conclusion, that the principles of a natural classification are to be drawn from the organs of fructification; for which conclusion Linnaeus declared him to be the first of systematists, while he thought de l’Obel and Kaspar Bauhin, who founded their arrangements on the habit only, scarcely deserving of notice. It appears, then, that Cesalpino obtained the subdivisions which he founded on the organs of fructification from _a priori_ views of the comparative value of organs, such as run through all Aristotelian philosophy. Of much interesting matter in the remainder of his introduction we must mention only that he makes the highest product of plants to be the fructification, of animals sense and movement, of man the intellect; and because the latter stands in need of no special bodily instruments, there is no specific difference in men, and therefore only one species of man. In his 14th chapter he gives in broad outline a view of the system of plants which he founded on the fructification, beginning with the least perfect; no one who knows the botanical writers of the 17th and 18th centuries will be surprised to find that Cesalpino admits the doctrine of ‘generatio spontanea’ in the case of the lower plants, and in a somewhat crude form; this came from the teaching of Aristotle, and even a hundred years later Mariotte endeavoured to set up a plausible defence of spontaneous generation on physical grounds even in highly developed plants. ‘Some plants,’ says Cesalpino, ‘have no seed; these are the most imperfect, and spring from decaying substances; they have only therefore to feed themselves and grow, and are unable to produce their like; they are a sort of intermediate existences between plants and inanimate nature. In this respect Fungi resemble Zoophytes, which are intermediate between plants and animals, and of the same nature are the Lemnae, Lichenes, and many plants which grow in the sea.’