This becomes especially clear to Goethe in Rome as Councillor Reiffenstein, during a walk with him, broke off a twig here and there and asserted that this, if stuck in the ground, must grow, that it must develop to a complete plant. In other words, the plant is an entity which develops in a succession of time intervals certain organs all of which, in relation to one another and also to the whole, are formed according to the same idea. Every plant is a harmonious whole of plants. As this became clear to Goethe, what was still necessary was only to make the individual observations which would render it possible to lay bare in detail the various stages of evolution which the plant sets forth out of itself. For this also what was needed had already occurred. We have seen that, in the spring of 1785, Goethe had made a study of seeds. From Italy he reported to Herder on May 17, 1787, that he had found quite clearly and beyond doubt the point where the germ is concealed. With this he had provided for the first stage of the plant life. But the unity of structure of all the leaves was very soon clearly enough manifest. Along with numerous other examples, Goethe found most especially in the fresh fennel the difference in this regard between the lower and the upper leaves, which are, nevertheless, always the same organ. On March 25, he asked that Herder be informed that his theory of the cotyledons was so refined that it would scarcely be possible to go further. Only a short steps remained to be taken in order to recognize also the petals, the pistils, and the stamens as metamorphosed leaves. The researches of the English botanist Hill could lead to this, which were then generally known and which dealt with the transformation of indivdual flower organs into others.

As the forces which organize the nature of the plant come into actual existence, they take on a series of structural forms. What was now needed was the living concept which united these forms backwards and forwards.

When we consider Goethe's theory of metamorphosis, as it appears from the year 1790, we find that for him this living concept was that of alternate expansion and contraction. In the seed the plant formation is most intensely contracted (concentrated). With the forming of leaves, there follows the first unfolding expansion, of the formative forces. What is pressed together to a point in the seed becomes spatially expanded in the leaves. In the calyx, the forces are again concentrated around an axial point. The corolla is produced by the next expansion. Stamens and pistils come about from the next concentration, the fruit through the last (third) expansion, whereupon the total force of the plant life (this Principle of the entelechy) conceals itself again in the most intensely contracted state in the seed. Although we have thus been able to trace fairly well all the details of the idea of metamorphosis up to its final application in the paper which appeared in 1790, it is not to its final application in the paper which appeared in 1790, it is not as easy to do the same thing with the concept of expansion and contraction. Yet one will not be going astray in assuming that this idea, deeply rooted anyway in Goethe's mind, was also interwoven already in Italy with the concept of plant-formation. Since the content of this idea is the fact of the greater or lesser spatial unfolding determined by the formative forces—and thus exists in that which is directly manifest to the eye in the plant—the idea would surely most easily arise when one undertakes to draw the plant in accordance with the laws of its natural process of formation. Now, Goethe found in Rome a bush-like carnation plant which revealed metamorphosis especially clearly. About this he wrote: “Seeing at hand no means for preserving this wonder-form, I undertook to sketch it exactly, and while doing this I gained more and more insight into the fundamental concept of metamorphosis.” Such sketches were probably often made later and this could then lead to the concept in question.

In September 1787, during his second sojourn in Rome, Goethe expounded the matter to his friend Moriz, and discovered how full of life and how manifest it became through such a presentation. He was always writing down how far he had progressed. It seems probable from this passage and some other remarks of Goethe that even the writing down of the theory of metamorphosis, at least sketchily, occurred in Italy. He says further: “In this way [in the presentation to Moriz] I could get something of my thoughts on paper.” It is beyond question that the work in the form in which it now exists was written down at the end of 1789 and the beginning of 1790. But to what extent this final composition was only editorial in character and what was added will be difficult to say. A book announced for the next Easter season which might, perhaps, contain the same ideas, induced him in the autumn of 1789 to work at his ideas and to arrange for their publication.