ORIGIN AND FUNCTION OF THE PROTOPLASMIC CONSTITUENTS IN PELOMYXA CAROLINENSIS

¹ The Johns Hopkins University

1. Centrifugation causes the protoplasmic constituents of Pelomsyxa carolinensis to stratify into definite layers which, in order of decrease in weight, are as follows: refractive bodies, food-vacuoles, nuclei, crystals, beta granules, hyaloplasm, contractile vacuoles, and fat.

2. The presence of at least one nucleus is necessary for normal locomotion and digestion, but not for ingestion of food in Pelomyxa. The length of life of Pelomyxa during starvation varies directly with the number of nuclei present.

3. The contractile vacuoles arise de novo in the hyaline cytoplasm. Their formation and functioning is not dependent on the presence of nuclei or beta granules.

4. The beta granules (mitochondria) do not play an active role in cell functions but, probably, merely give visible evidence of submicroscopic changes taking place in the hyaloplasm.

5. The vacuole-refractive bodies and the crystals are formed from the food in the food-vacuoles of Pelomyxa and are used in the formation of the refractive bodies.

6. The refractive bodies function as food reserve in the cell. Their complete removal does not impair any of the cellular activities.