Abstract
1. The existence of vitamin A and fat in various parts of the lamprey was histochemically observed under a fluorescence microscope.
2. In the muscular tissue vitamin A was found to exist in the fat droplets in the subcutaneous adipose and the intermuscular tissues as fine granules independently of the fat in the boundary line between the muscular and connective tissues.
3. In the liver most of vitamin A was shown to be much dissolved in the droplets of the fat contained in the cells.
4. In the kidney most of vitamin A was found as minute fluorescent granules in the renal corpuscles and uriniferous tubules. They are seemingly free from fat droplets.
5. The milt showed the vitamin A existing in the fat droplets in the interstitium among the tubuli seminiferi. No vitamin was found in the tubli seminiferi itself.
6. Most of the vitamin A in the ovary was found in the adipose tissue among the follicles. The ovarian cyst had fine fluorescent granules of the vitamin, and the corpus luteum had a diffusive fluorescence. Both kinds of fluorescence disappeared in about the same length of time under ultraviolet-ray irradiation.
7. The alimentary canal showed a majority of vitamin A existing in fine fat droplets in the tela submucosa and lamina propria mucosae. It also had a small part of the vitamin independently of the fat in the cells of the mucous epithelium, serous membrane, and muscular layer. Under ultraviolet irradiation the vitamin in the fat disappeard more slowly than that free from fat.
