1. Magnesium salts tend to increase the water in oil phase of oil and water emulsions more than do calcium salts.
2. This action is due to the much greater solubility of magnesium oleate in oil and in other organic solvents.
3. The injection of magnesium salts into the body therefor tends to diminish the oil in water phase of a balanced emulsion; and the injection of calcium salts tends to restore it to the normal physiological balance.
4. The oridinary soporific drugs and also the "coal tar" analgesics tend to produce water-in-oil emulsions and thus to diminish ionic interchange between the interior and exterior of the nerve cells. This seems to furnish an explanation of the analgesic action of these drugs.
5. The effects of alkaloids upon magnesium sulphate action cannot be explained upon this basis until more is known regarding the physical and chemical conditions under which they circulate in the blood and are adsorbed by the tissues.