Sedatives are medicinal substances employed to diminish the frequency of the action of the circulation, their therapeutic influence being due, it is thought, to a stimulant character. They reduce vascular excitement, and while relieving irritability and irregularity of the heart's action, their first effect is to restore its tone and force when it is in a morbidly depressed condition. Substances known as refrigerants, which possess the power of diminishing febrile heat, allaying thirst, restoring the secretions, and which comprise almost all of the neutral alkaline salts, are also included with sedatives. Among the class known as sedatives are digitalis, American hellebore (veratrum viride), white hellebore (veratrum album), yellow jasmine (gelsemium), tartar emetic, nitrate of potassium, etc., etc. Among the class known as refrigerants are borate of soda, citrate of potassium, acetate of ammonia, spirit nitrous ether, and vegetable acids.