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THE NATURAL SCIENCES. 445
diligently worked at, and afforded material for the solution
of many questions of geology and anthropology.
In botany various attempts were made to discover a
natural system of plants. ADANSON declared that " nature
everywhere exhibits to us natural groupings," and was of
opinion that classification should not certainly be based
upon the similarities and differences of one particular
organ, but only upon the collective phenomena and
characteristics of the organism. In order to reveal this
system he compared individual plants in respect of their
various organs and arranged them into classes of varying
degrees of affinity according to the greater or less correspondence
between them. His method of classification was,
above all things, wanting in lucidity, and could not, therefore,
gain for itself any approval.
A more correct method was introduced by A. L. DE
JUSSIEU, A. PYRAMUS DE CANDOLLE, ROBERT BROWN and
others: they insisted first of all upon an accurate definition
and delimitation of the families of plants, and did a quantity
of valuable preparatory work in this direction. A. P DE
CANDOLLE, who himself described with great care more than
one hundred families, founded the doctrine of the symmetry
of the plant-form. The investigations of J. GAERTNER
upon the fruits and seeds of plants and R. BROWN'S monographs
were of fundamental importance for morphology.
GOETHE'S doctrine of metamorphosis excited the attention
of philosophers of nature rather than that of men of
science. It was of a confused and indefinite character, and
was first explained scientifically by ALEXANDER BRAUN
who brought forward valuable information upon the form
of the leaf and the development of the plant.* The
anatomy of plants was diligently worked at by BRISSEAU-
MIRBEL, the younger MOLDENHAWER, LINK, MEYEN, HUGO
MOHL and others, who succeeded in giving definiteness to
men's views upon the structure of plants. Their micro-
* WIGAND: Geschichte und Kritik der Lehre von der Metamorphose der
Pflanzen, Leipzig 1846.