Abstract
Gudernatsch (1912) for the first time elucidated that thyroid substance acceleretes the metamorphosis of amphibia. Numerous works on the metamorphosis have been published. However, mechanism of the so-called metamorphotic phenomena, seen in mouth, muscle, respiratory organ, digestive tract, skin, tail, etc. during spontaneous metamorphosis or artificial one induced by the administration of thyroid substance still remains in perfect obscurity.
To obtaine the clue of the problem, we carried out investigations with larvae of Rana catesbiana on change in Cu+++ and Zn++ which are considered to have important bearing on physiological activity of tissue or cells, and muscular structure of the tail in stages of the tadpole and metamorphosis was examined polarographically and histochemically. As the sign of metamorphosis, the tail absorption, the most conspicuous metamorphotic phenomenon, was uesd. In the tadpole stage, a large, amount of Zn was found in the vascular wall, subcutaneous tissue, and muscle, while Cu was scarce. On the contrary, in the metamorphotic stage, a large amount of Cu was found in the muscle and Zn was relatively decreased. These were confirmed quantitatively by the results of polarography.
