INCOMPATIBLES.--Caustic alkalies; antagonize physiologically by pilocarpine and physostigma throughout almost whole range of its influence, and opium within a certain limitation, prevents the respiratory failure, which is the cause of death. ACTION.--Belladonna is an irritant narcotic, a mydriatic, an antispasmodic and anodyne. In small doses a cardiac, respiratory and spinal stimulant; in large doses a paralyzer of the sensory and motor nerve endings and a stimulator of the entire sympathetic system. It produces dryness of the mucous membrane of the throat, mouth, nose and pharynx, and at first lessens the gastric and intestinal secretions, but soon produces them in large quantities. It is anti-galactogogue, that is, it arrests secretion of milk. The heart rate is at first slowed, but soon becomes very rapid and vigorous, the pulse being doubled in rapidity; arterial tension is raised and the circulation greatly increased. The pupils are dilated by the local or systemic use of the drug. The brain is congested by belladonna, a busy delirium being produced, and hallucinations with mental disorder, due to a selective action on the cell of the gray matter. The spinal cord is stimulated from the second cervical vertebrae to the tenth dorsal, resulting in paralysis of the motor nerves, both central and peripheral, power being lost in hind extremities first. The respiration is increased and the temperature is raised by the increased circulation; metamorphosis is greatly promoted. Belladonna and atrophine are rapidly diffused and quickly eliminated by the kidneys. By its paralyzing effect on the terminal nerve filaments, it relaxes the bronchial tubes and checks the secretion of the bronchial mucous membrane; it checks secretion of saliva and milk in the same way and causes dryness of the skin. USES.--Belladonna and atrophine is indicated anywhere that an antispasmodic and anodyne is needed. Is serviceable in catarrh, pharyngitis and bronchitis to check secretion in second stage; heaves, especially asthmatic heaves, combined with gelsemium and lobelia, followed by Fowler’s Solution; in influenza, it stimulates the weakened heart, besides having other good effects. In the first stage of respiratory diseases, belladonna alone, or combined with aconite or other febrifuges and expectorants; in cough, especially spasmodic or when due to irritation of the throat; in heart failure or heart weakness, hypodermic injections of atrophine are beneficial; in spasmodic colic one to two drachms of the fluid extract to a dose, but one drachm is usually sufficient; as a powerful antispasmodic and anodyne, atropine and morphine combined; small doses are given in constipation of the bowels, combined with nux vomica; small doses with purgatives are said to aid their action.