=*Myrrha (Myrrh.), Myrrh, U.S.P.= (Gum Myrrh).--A gum resin. ACTION AND USES: Protective and local stimulant to the mucous membranes. Internally, carminative. DOSAGE: 0.5 Gm. or 8 grains (U.S.P.). _*Tinctura Myrrhae (Tr. Myrrh.), Tincture of Myrrh, U.S.P._--Myrrh (20%) in alcohol. Absolute alcohol content about 87 per cent. DOSAGE: 1 Cc. or 15 minims (U.S.P.). =NEBULAE, SPRAYS.=--Spray solutions, intended for the application of medicaments in solution to the throat and nose by means of suitable atomizers. For Nebula Aromatica, see under =Petrolatum Liquidum=; for the various other sprays, see under =Eucalyptol=, =Menthol= and =Thymol=. =Nitrogenii Monoxidum (Nitrogen. Monox.), Nitrogen Monoxide, U.S.P.= (Nitrous Oxide, "Laughing Gas").--N{2}O. A colorless gas with a slight characteristic odor and a sweetish taste. ACTION AND USES: For inhalation anesthesia. =*Nux Vomica (Nux Vom.), Nux Vomica, U.S.P.= (Strychni Semen, P.I.).--Seeds yielding not less than 2.5 per cent. of alkaloids, chiefly strychnine and brucine. ACTION AND USES: Used as bitter stomachic and tonic, depending on its strychnine. DOSAGE: 0.06 Gm. or 1 grain (U.S.P.). _*Extractum Nucis Vomicae (Ext. Nuc. Vom.), Extract of Nux Vomica, U.S.P._ (Powdered Extract of Nux Vomica, Nucis Vomicae Extractum P.I.).--Yields about 16 per cent. of alkaloids. DOSAGE: 0.015 Gm. or 1/4 grain (U.S.P.). _Fluidextractum Nucis Vomicae (Fldext. Nuc. Vom.), Fluidextract of Nux Vomica, U.S.P._--Nux vomica (100%) yielding about 2.5 per cent. of alkaloids. Absolute alcohol content about 60 per cent. DOSAGE: 0.05 Cc. or 1 minim (U.S.P.). _*Tinctura Nucis Vomicae (Tr. Nuc. Vom.), Tincture of Nux Vomica, U.S.P._ (Strychni Tinctura, P.I.).--Nux vomica (10%) yielding about 0.25 per cent. of alkaloids. Absolute alcohol content about 71 per cent. DOSAGE: 0.5 Cc. or 8 minims (U.S.P.). =OLEA INFUSA (OL. INF.), INFUSED OILS, N.F.=--Liquid preparation made by extracting drugs by fixed oils. =OLEATA, OLEATES.=--Oleates are combinations of alkaloids or metallic oxids with oleic acid or with mixtures of oleic acid with a fixed oil. They have no real advantage over simpler ointments. For the official oleates see under the names of the respective drugs. =OLEORESINAE, OLEORESINS.=--Oleoresins are thick liquid preparations made by extracting the drug with ether, alcohol or acetone. For the official oleoresins see under the names of the respective drugs. =OLEOSACCHARA (OLEOSACCHARA), OIL-SUGARS, N.F.= (Elaeosacchara).--Mixtures of volatile oil (2%) with sugar in fine powder. =Oleum Aethereum (Ol. Aether.), Ethereal Oil, N.F.=--A volatile liquid consisting of equal volumes of heavy oil of wine (chiefly ethyl esters of sulphuric acid) and ether. An indefinite and obsolete ingredient of the medieval "Hoffmann's anodyne."