The data for observation, from which in Goethe's own fashion we shall
start, have been selected as best for our purpose, quite independently
of the data used by Goethe himself. Our choice was determined by the
material available when these pages were being written. The reader is
free to supplement our studies by his own observation of other plants.

*

Plates II and III show two series of leaves which are so arranged as to
represent definite stages in the growth-process of the plant concerned.
In each sequence shown the leaves have been taken from a single plant,
in which each leaf-form was repeated, perhaps several times, before it
passed over into the next stage. The leaves on Plate II come from a
Sidalcea (of the mallow family), those on Plate III from a Delphinium.
We will describe the forms in sequence, so that we may grasp as clearly
as possible the transition from one to another as presented to the eye.

Starting with the right-hand leaf at the bottom of Plate II, we let our
eye and mind be impressed by its characteristic form, seeking to take
hold of the pattern after which it is shaped. Its edge bears numerous
incisions of varying depths which, however, do not disturb the
roundness of the leaf as a whole. If we re-create in our imagination
the 'becoming' of such a leaf, that is, its gradual growth in all
directions, we receive an impression of these incisions as 'negative'
forms, because, at the points where they occur, the multiplication of
the cells resulting from the general growth has been retarded. We
observe that this holding back follows a certain order.

We now proceed to the next leaf on the same plate and observe that,
whilst the initial plan is faithfully maintained, the ratio between the