Conclusions from the First Main Part of these Lectures
In finishing our chapter on inheritance, we at the same time have finished the first main part of our lectures; that part of them which has been devoted exclusively to the study of the morphogenesis of the individual, including the functioning of the adult individual form. We now turn to our second part, which is to deal with the problems of the diversities of individual forms, with morphological systematics. The end of our chapter on inheritance has already led us to the threshold of this branch of biological science.
The chief result of the first main part of our lectures has been to prove that an autonomy of life phenomena exists at least in some departments of individual morphogenesis, and probably in all of them; the real starting-point of all morphogenesis cannot be regarded as a machine, nor can the real process of differentiation, in all cases where it is based upon systems of the harmonious equipotential type. There cannot be any sort of machine in the cell from which the individual originates, because this cell, including both its protoplasm and its nucleus, has undergone a long series of divisions, all resulting in equal products, and because a machine cannot be divided and in spite of that remain what it was. There cannot be, on the other hand, any sort of machine as the real foundation of the whole of an harmonious system, including many cells and many nuclei, because the development of this system goes on normally, even if its parts are rearranged or partly removed, and because a machine would never remain what it had been in such cases.
If our analytical discussions have thus led us to establish a typical kind of vitalism, it follows that we can by no means agree with Wilhelm Roux in his denomination of the analytical science of the individual form and form-production as “Entwickelungsmechanik,” “developmental mechanics,” a title, which, of course, might easily be transformed into that of “morphogenetic mechanics,” to embrace not only normal development, but restitution and adaptation too. We feel unable to speak of “mechanics” where just the contrary of mechanics, in the proper meaning of the word, has been proved to exist.
Names of course are of comparatively small importance, but they should never be allowed to be directly misleading, as indeed the term “Entwickelungsmechanik” has already proved to be. Let us rather say, therefore, that we have finished with this lecture that part of our studies in biology which has had to deal with morphogenetic physiology or physiological morphogenesis.
Once more we repeat, at this resting-point in our discussions, that both of our proofs of life-autonomy have been based upon a careful analysis of certain facts about the distribution of morphogenetic potencies in two classes of morphogenetic systems, and upon nothing else. To recall only one point, we have not said that regeneration, merely because it is a kind of restitution of the disturbed whole, compels us to admit that biological events happen in a specific and elemental manner, but, indeed, regeneration does prove vitalism, because it is founded upon the existence of certain complex-equipotential systems, the analysis of the genesis of which leads to the understanding of life-autonomy. This distinction, in fact, is of the greatest logical importance.