We are not, however, studying these things for cytological, but for morphogenetical purposes, and for these the cleavage phenomenon itself is less important than the organogenetic result of it: all our subjects resulted in *absolutely normal* organisms. Now, it is clear, that the spatial relations of the different nuclear divisions to each other are anything but normal, in the eggs subjected to the pressure experiments; that, so to say, every nucleus has got quite different neighbours if compared with the “normal” case. If that makes no difference, then there *cannot* exist any close relation between the single nuclear divisions and organogenesis at all, and the conclusion we have drawn more provisionally from the whole development of isolated blastomeres has been extended and proved in the most perfect manner. There ought to result a morphogenetic chaos according to the theory of real “evolutio” carried out by nuclear division, if the positions of the single nuclei were fundamentally changed with regard to one another (Fig. 6). But now there resulted not chaos, but the normal organisation: therefore it was disproved in the strictest way that nuclear divisions have any bearing on the origin of organisation; at least as far as the divisions during cleavage come into account. [Illustration: Fig. 6.--Pressure-experiments on Echinus. *a*_1 and *b*_1. Two normal cleavage stages, consisting of eight and sixteen cells. *a*_2 and *b*_2. Corresponding stages modified by exerting pressure until the eight-cell stage was finished. See text.] On the egg of the frog (O. Hertwig), and on the egg of annelids (E. B. Wilson), my pressure experiments have been carried out with the same result.[17] [17] In the pressure experiments I had altered the relative position of the nuclei *in origine*. In later years I succeeded in disturbing the arrangement of the fully formed cells of the eight-cell stage, and in getting normal larvæ in spite of that in many cases. But as this series of experiments is not free from certain complications--which in part will be understood later on (see page 73)--it must suffice here to have mentioned them. (For further information see my paper in *Archiv. f. Entwickelungsmechanik*, xiv., 1902, page 500.) ON THE INTIMATE STRUCTURE OF THE PROTOPLASM OF THE GERM Nuclear division, as we have seen, cannot be the basis of organogenesis, and all we know about the whole development of isolated blastomeres seems to show that there exists nothing responsible for differentiation in the protoplasm either.