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CYXG

pended. The acid thus formed, however, is only permanent for afew hours.

Cyanogen, or Prussine, a gas obtained by heating perfectly dry prussiateof mercury, in a glass retort, or a tube closed at one extremity. Itfirst blackens, then liquefies, and the cyanogen comes over, and mustbe collected over mercury. It forms compounds with the metalscalled cyanides, and with salifiable bases called cyanates, or hydro-eyanates, and cyanurets.

Cyanurktum Hydrargyri. D. Mix together six parts of cyanuretof iron, add five parts of the nitric oxide of mercury, and fortyparts of distilled water, hot. Boil for half an hour, stirring it thewhile, and then filter through blotting-paper. Wash the residuewith distilled water, evaporate the filtered solutions, and cool toobtain crystals.'Medicinally it is more convenient than the prussic acid for externalapplications.

Cyanuretum Potassii. New. Cyanuret of Potass is prepared by ex-posing to a long-continued heat a portion of ferro-cyanate (ferru-ginous prussiate) of potass, till the cyanuret of iron is decomposed,and the potassium remains, the residuum being impure cyanuret ofpotassium, which is dissolved in water, and the impurities subside.It is very pure, white, and transparent.Medicinally the dose is gr. \ to gr. j in scrofula, &c.

Cyanuretum Zinci. New. Cyanuret of zinc is prepared by precipi-tating the sulphate of zinc by the hydrocyanate of potass, when atriple hydrocyanate of zinc is formed; which, when well dried andcalcined to a dark red, is the cyanuret of zinc, but is also mixed withcyanuret of potass.Medicinally the dose gr. \, cautiously increased to gr. j, is a powerfulvermifuge, and a substitute for hydrocyanic acid.

Cyclamen Europium. P. Common Cyclamen, the fresh root ofWhich is aromatic, acrid, bitter, and drastieo-cathartic in doses of ^ssto 5J of the powder, as a vermifuge, and in schirrous tumours, gan-glions, &c.

Cydonme Semina. L. P. Quince Seeds, Fyrus cydonia. The fruitand seeds of the quince are mucilaginous, cooling, and astringent,given in cases of vomiting; in form of infusion as an injection ingonorrhoea; and externally in excoriations, being more viscid thangum arabic; but it does not keep.Enters into Decoct. Cydoniue. L.

Cynapia. This, inaccurately given Cynopia, is the alkaline base ofJEtiiusa Cynapium, or fool's parsley.

Cyngolossum Officinale. P. Hound's Tongue. A feeble are-