=Opium.=—This is the dried juice of a species of poppy growing in Asia. It contains several alkaloids, the chief of which are _morphin_ and _codein_. From morphin are prepared artificially two alkaloids—_apomorphin_ and _heroin_. Opium depresses the brain, depresses the respiration, stimulates the heart slightly, lessens the peristaltic movements of the bowel, and diminishes all secretions, except the sweat. It is employed to induce sleep, to relieve pain, to allay cough, to check diarrhea, and to promote perspiration. _Opium-poisoning_ is marked by three stages: the _first_ stage is short and characterized by mental exhilaration; in the _second_ stage the pupils are greatly contracted (pin-point), the respirations are slow, the pulse is slow and full, and there is deep stupor. In the _third_ stage the patient can no longer be aroused (coma), the respiration becomes shallow and irregular, the pulse becomes rapid and weak, the pupils finally dilate, and the patient dies from failure of the respiration. Even after small doses of opium many patients suffer from headache and nausea. Children are much more sensitive to its action than adults. Morphin resembles opium in action, but is more powerful, less nauseating, and less constipating. Codein is less powerful as a hypnotic and less depressing than morphin. The _dose_ of _opium_ is from ½ to 1 grain (0.03-0.65 gm.); of the _Extract of Opium_ (Extractum Opii), ⅛ to ½ grain (0.008-0.03 gm.); of the _Tincture of Opium_ or _Laudanum_ (Tinctura Opii), 10 to 20 minims (0.6-1.2 c.c.); of the _Camphorated Tincture of Opium_ or _Paregoric_ (Tinctura Opii Camphorata), ½ to 4 drams (2-15 c.c.); of _Dover’s Powder_ (Pulvis Ipecacuanhæ et opii), 5 to 10 grains (0.3-0.6 gm.); of _morphin_ and its salts (sulphate, hydrochlorate, etc.), ⅛ to ½ grain (0.008-0.03 gm.), and of _codein_, ½ to 1 grain (0.03-0.06 gm.). _Heroin_ is chiefly used to allay cough. The _dose_ is from ¹/₁₂ to ⅛ of a grain (0.005-0.008 gm.). _Apomorphin_ is employed as an emetic and as an expectorant in bronchitis. The _dose_ as an emetic is from ⅒ to ⅙ of a grain (0.006-0.01 gm.), always hypodermically; the _dose_ as an expectorant is from ¹/₂₀ to ¹/₁₀of a grain (0.003-0.006 gm.), always by the mouth. =Paraldehyd.=—This is an oily liquid, having a peculiar unpleasant odor and taste. It is used chiefly as a hypnotic. While comparatively safe and reliable, its disagreeable taste and persistent odor on the breath detract from its usefulness. The _dose_ is from ½ to 1 dram (2-4 c.c.), in some pleasant vehicle.