1. We have confirmed previous work which shows that the injection of bile increases the tone of the vagus nerve, and that this action can be abolished after the administration of atropine. 2. We have found that the amount of bile salts in a lethal dose of pig's bile for dog's will, if inejcted alone, produce neither a fall in blood pressure nor a slowing in rate. 3. We have found that the amount of pigment in a lethal dose of the bile will, if injected alone, cause death with slowing of the heart and lowering of blood pressure. 4. We have found that the bile pigment in combination with calcium or sodium is less toxic than uncombined pigment. 5. We have found that in experimentally produced jaundice the calcium content of the blood is increased, while that of the liver, muscle and brain are decreased. 6. We are of the opinion that increase in calcium in the blood is a protective mechanism against the circulating pigments of obstructive jaundice.