Horváth Géza (szerk.): A Magyar Természettudományi Múzeum évkönyve 8. (Budapest 1910)

Soós, L.: A Helix arbustorum hím csirasejtjének fejlődése

33-2 D, L. SOÓS determined shape when the chromomere lines connecting the groups become drawn to one of the groups, we may say they become absorbed by it, and thus the groups separate from one another (Pl. VIII., Fig. 8). The formation of the chromosomes is completed when the chromomeres melt together into a homogeneous mass. The author is of the opinion that these facts cannot be brought into agreement with the hypothesis of the individuality. The dissolving of the crhomosomes into chromomeres can be observed quite distinctly, and thus it can be stated that the chromosomes undoubtedly lose their individuality. MARCUS (62) is of the opinion that the chromosomes retain their independence even in such cases, because it is not impossibly that at the time of union of the chromomeres these part unite again which formed, before dissolving, the same chromosome. But this suggestion cannot be supported by facts. On the contrary, I hold it more probable that the chromosomes after dissolving become restored anew by the process of chromomeres of different chromosomes being united to form a new chromosome. This suggestion is based upon the physiological process in sense of which substances ooze from the cytoplasm to the nucleus, and from the nucleus to the cytoplasm. In the first part of the growth period the nucleus increases considerably. The substances requisite to the growth must past through the cytoplasm, or perhaps formed parts of it, i. e. diosmotic processes take place between the cytoplasm and the nucleus. In the second part of the growth period, however, the amount of the cytoplasm increases, and synchronously the chromatin diminishes, which is shown by the fact that the nucleus is then less stainable (cf. Pl. VII.. Fig. 14., Pl. VIII., Figs. 3—4.). 1 have already mentioned this fact. There interests us now only the fact that some substances of the nucleus get into the cytoplasm, the futher fate of which can also be determined. It is shown by this fact that in the second part of the growth period diosmotic processes also takè place between the cytoplasm and the nucleus. The osmotic current holds the whole substance of the nucleus in constant motion, and it takes with itself the chromomeres as well, the adhesive matter of which has disappeared by the dissolving of the linin. As the last result the reciprocal position of the chromomeres changes, and it is quite impossible for the chromomeres of the former chromosomes to unite again, therefore after restoration of the chromosomes we have to do with «individuals» which are not identical with the former ones. Thus the author is of the opinion that the chromosomes cannot be regarded as individuals, but as «tactic groups» («taktische Verbindungen») which obtain their form in the