“…The mean and range of results for copper and magnesium per gram of cells are similar to those obtained by other workers (3,(49)(50)(51)(52) (14,59) the total cation concentration of plasma. Some of the discrepancy can be attributed to the inaccuracy of methods in which erythrocyte values are derived from analyses performed on whole blood and serum (5,40,44,56,58) and to a failure to express the plasma cation concentration on the basis of plasma water (14).…”