Abstract
The author has performed observations on the relation between elaboration of mucous substance and synthesis of nucleic acid, and on the alteration of intra-nuclear vesicle and growth of blood cell-like granule. The localization and identification of the two nucleic acids, ribonucleic and desoxyribonucleic, have been determined for the 5th instar larval prothoracic gland of Bombyx mori. The determinations were made by the use of pyronin-methyl green staining, POLLISTER and RIS' TCA method, and FEULGEN reaction. The result obtained is as follows:
1. Mucous substance of the prothoracic gland was produced during the period after the lapse of about a quarter of the age to the pre-pupal stage.
2. The intra-nuclear vesicle which is observed in the nucleus at the early stage of the 5th instar is released from the nuclei into the cytoplasm later. It seems that this is the same phenomena which is known as “Kern Secretion” in the parenchymal cell of the vertebrate.
3. In the secreted substances in the prothoracic gland mucous substance and blood cell-like granules are distinguished. And many blood cell-like granules are seen in the cytoplasm close to the trachea.
4. The relation between elaboration of secretion and synthesis of PNA is as intimate as in the 4th instar larva.
