THE STUDY OF PLANTS IN ANCIENT AND MODERN TIMES. 13 
continual struggle to become earth on the one hand and air on the other, unmixed 
metal at one end, and dual air at the other. A plant is a radius, which becomes 
single towards the centre, whilst it divides or unfolds towards the periphery; it is 
not therefore an entire circle or sphere, but only a segment of one of those figures. 
The individual animal, on the contrary, constitutes of itself a sphere, and is there- 
fore equivalent to all plants put together. Animals are entire worlds, satellites or 
moons, which circle independently round the earth; whereas plants are only equal 
to a heavenly body in their totality. An animal is an infinitude of plants. A 
blossom which, when severed from the stem, preserves by its own movement the 
galvanic process or life, is an animal. An animal is a flower-bubble set free from 
the earth and living alone in air and water by virtue of its own motion.” 
Page after page of the writings on Natwre-philosophy of Oken (1810) and 
other contemporary naturalists is filled with interminable statements of the same 
kind. At the present day it seems scarcely eredible that such propositions were 
then received with admiration as profound and ingenious utterances, and that they 
were even adopted as mottoes for botanical and geological treatises. For example, 
it is worthy of record that as late as the year 1843 the Austrian botanist Unger 
made use of the last of the flowers of rhetoric above quoted from Oken’s Nature- 
philosophy as a motto for one of his first works on the history of development, 
the title of which is Plants at the Moment of their becoming Animals. 
The general divisions or systems of the vegetable kingdom which were evolved 
by adherents of the school of Nature-philosophy were, as may be imagined, just as 
absurd as the speculations on which they were based. In his Philosophical Systems 
of Plants Oken develops in the first place the idea that the vegetable kingdom 
is a single plant taken to pieces. Inasmuch as the ideal highest plant is composed 
of five organs, there must likewise be five classes: root-plants, stem-plants, leaf- 
plants, flower-plants, and fruit-plants. The world is fashioned out of the elements: 
earth, water, air, and fire. Hereupon is founded a classification of root-plants into 
earth-plants or lichens, water-plants or fungi, air-plants or mosses, and light-plants 
or ferns. Proceeding from the assumption that all the groups are parallel and that 
the principle of classification for each group is always given by the one preceding 
it, we have next, to take one instance, the second elass—that of stem-plants— 
divided (in accordance with the subdivision of earth into earths, salts, bronzes, and 
ores) into earth-plants or grasses, salt-plants or lilies, bronze-plants or spices, and 
ore-plants or palms. 
SCIENTIFIC METHOD BASED ON THE HISTORY OF DEVELOPMENT. 
Though as we see the doctrine of metamorphosis, with its conception of a 
typical plant, degenerated thus into the most barren of fancies, still from it originated 
the line of research based on the history of development which has since borne 
fruit in every department of botany. Observers arrived at the conviction that 
every living plant undergoes a continuous transformation which follows a definite 
