Addison's disease Caused by partial or total failure of adrenocortical function; characterized by a bronze-like skin color and mucous membranes, anemia, weakness, and low blood pressure. ad libitum At the discretion of the performer. Giving license to alter or omit a part. affusion Pouring on of liquid, as in baptism. ague Alternating periods of chills, fever, and sweating. Used in reference to the fevers associated with malaria. aletris farinosa (Colicroot, star grass, blackroot, blazing star, and unicorn root ) Bitter American herb of the Bloodwort family, with small yellow or white flowers in a long spike (Aletris farinosa and A. aurea). algid Cold; chilly. alkanet European perennial herb (Alkanna tinctoria) having cymes of blue flowers and red roots. The red dye extracted from the root. Plants of the Eurasian genus Anchusa, having blue or violet flowers grouped on elongated cymes. allyl Univalent, unsaturated organic radical C3H5. aloin Bitter, yellow crystalline compound from aloe, used as a laxative. alum Double sulfates of a trivalent metal such as aluminum, chromium, or iron and a univalent metal such as potassium or sodium, especially aluminum potassium sulfate, AlK(SO4)2 12H2O, widely used in industry as clarifiers, hardeners, and purifiers and medicinally as topical astringents and styptics. anemonin Acrid poisonous compound containing two lactone groups; obtained from plants of the genus Anemone and genus Ranunculus, containing the buttercups. aneurysm (aneurism) Localized, blood-filled dilatation of a blood vessel caused by disease or weakening of the vessel wall. animadversion Strong criticism. Critical or censorious remark: anise Aromatic Mediterranean herb (Pimpinella anisum) in the parsley family, cultivated for its seed-like fruits and the oil; used to flavor foods, liqueurs, and candies. anodyne Relieves pain. antipyrine (antipyrin, phenazone) Analgesic and antipyretic (reduces fever) C11H12N2O formerly used, but now largely replaced by less toxic drugs such as aspirin. antrum Cavity or chamber, especially in a bone. Sinus in the bones of the upper jaw, opening into the nasal cavity. apomorphine Poisonous white crystalline alkaloid, C17H17NO2, derived from morphine and used to induce vomiting. arnica Perennial herbs of the genus Arnica. Tincture of the dried flower heads of the European species A. montana, applied externally to relieve the pain and inflammation of bruises and sprains. articular Relating to joints: the articular surfaces of bones. asafetida (asafoetida) Fetid (offensive odor) gum resin of Asian plants of the genus Ferula (especially F. assafoetida, F. foetida, or F. narthex). It has a strong odor and taste, and was formerly used as an antispasmodic and a general prophylactic against disease.