THE DISTRIBUTION OF ELECTROLYTES IN PHASCOLOSOMA MUSCLE

¹ From the Department of Zoölogy, Columbia University, and the Marine Biological Laboratory, Woods Hole, Mass.

An analysis is presented of the major inorganic constituents of Phascolosoma muscle and body fluid. As is usually found in muscle tissue, potassium is more concentrated in the tissue than in the body fluid or in sea water. Calcium is in about the same concentration while sodium and chloride are in the tissue in lower concentrations than they exist in the external medium.

Sodium and chloride appear to be extracellular in these muscles, most of the potassium and some calcium are intracellular. Parallel analyses of muscles for different elements show that the cells can take up considerably more potassium than they normally contain without an increase in chloride. Some calcium can also be taken up by the cells.

These findings are discussed briefly in connection with their bearing on problems of permeability to electrolytes of muscle cells.