APPETITE, LOSS OF.--A frequent accompaniment of various digestive disturbances, especially of gastric complaints. It depends on a weakened or insufficient amount of the digestive fluids, particularly of the hydro chloric acid in the stomach. The tongue loses its normal moist appear ance ; it becomes dry, and is coated the accumulation of the cells cast off from its upper surface. As a general thing the condition of the tongue forms a fairly safe indication of the condition of the stomach, but in some cases even the most obstinate and serious gastric illness may cause little or no change in the appearance of the tongue. Loss of appetite alone does not constitute an absolute criterion of the extent or nature of a disease. It may he present in very slight digestive disturbances and absent in the most serious. In conclusion, attention must be called to the loss of appetite, which is a purely nervous condition and which may be recognised only with the greatest difficulty by the physician.
APRAXIA.—See SPEECH DISTURBANCES.
ARNICA.—The dried flower-heads and dried roots of Arnica monlana, a plant native to Europe, grown extensively in Germany and Switzerland, and sparingly found cultivated in the United States. It contains an active volatile oil which is largely responsible for its physical effects. The principle,
arnicine, is also described, but is imperfectly known. Applied to the skin, arnica causes irritation, and if the application is permitted to continue it may cause•inflamma.tion of the skin, with the formation of blisters. Taken internally it stimulates the mucous membrane of the mouth, (esophagus, and stomach, and may act as a bitter, improving the appetite. It acts like others of the volatile oils, causing a reflex stimulation of the heart-beat, dilatation of the blood-vessels of the surface of the body, increased flow of perspiration, and also increased flow of urine. In large doses it may cause symptoms of burning in the mouth and stomach, nausea, vomiting, intense prostra tion, with dilated pupils and rapid, feeble heart, cold extremities, occasional convulsions, irritation of the kidneys, and death from exhaustion. Lini ments containing arnica are in wide favour with the laity, hut it is highly improbable that they have any specific action beyond their mild counter irritant effects. The alcohol in many of these liniments is probably an important adjunct in explaining the therapeutic results obtained. Arnica is too dangerous a drug to be employed to any great extent for internal medication.