463
product is obtained when the calcination is performed in the same vesselin which the nitrate was formed, and without Stirling, as directed in theDublin Pharmacopoeia (Dr. Barker, Observ. on the Dubl. Pharm.)
When quicksilver and the diluted nitric acid are digested together, themetal is oxidized at the expense of part of the acid, while binoxide ofnitrogen escapes, and, combining with oxygen of the air, becomesnitrous acid. The oxidized metal unites to some undecomposed acid toform a nitrate. If no heat be applied, a nitrate of the protoxide onlyis procured; but when heat is employed, a portion of nitrate of theperoxide is also produced. The following diagram will explain theformation of the protonitrate :—
REAGENTS.
RESULTS.
30——--—1 eq. Binoxide Nitrog’. 30
606 \ 3 e 1* Oxide Merc. 630
162--- >--> 3 eq. Protonitr. Mercy 792
When nitrate of mercury is heated, decomposition takes place: thenitric acid is resolved into oxygen and nitrous acid, the first of whichcombines with the protoxide of mercury, forming therewith the binoxide,while the nitrous acid escapes.
REAGENTS.
{
Some pcrnitrate of mercury usually remains undecomposed, but thequantity is small. Mr. Braude states that 100 pounds of mercury with48 lbs. of nitric acid (sp. gr. T48) yielded 112 pounds of nitric-oxide ofmercury. Hence 3 pounds of nitric acid must have remained in com-bination with the oxide.
Properties.— It occurs in bright tile-red or scarlet crystalline grainsor scales. When quite free from nitrate of mercury, it is insoluble inwater; but owing to the presence of a small quantity of nitrate, thenitric-oxide of mercury of commerce is usually slightly soluble in water.Dr. Barker (op. cit.) found that 1000 parts of water took up 0'62 of thisoxide. The other properties and characteristics of this compound arethe same as those of the last-mentioned preparation (vide HydrargyriBinoxydum)
Purity.-— Thepresenceof some undecomposed nitrate mayberrecognisedby heating the suspected nitric-oxide of mercury, when nitrous vapours areevolved, and by boiling in water, when a solution is obtained, from whichlime-water and hydrosulphuric acid throw down precipitates. The nitric-oxide of mercury is completely dissipated by heat: hence the presenceof non-volatile matters (as red-lead) might be readily detected. Heatedbefore the blow-pipe on charcoal, the mercurial oxide is reduced anddissipated, but if red-lead be present, globules of metallic lead will be leftbehind.
Physiological Effects. —Its local action is that of a powerful irri-tant (vide Hydrargyri Binoxydum). When the nitric-oxide containsnitrate of mercury, its topical influence is rendered more energetic. Itsconstitutional effects are the same as those of other mercurials.
Fabricius Hildanus, Bartholinus, Langius, and Jacobs (quoted byWibmer, Wirkuny d. Arzneim. iii. 69), have reported cases in which theexternal use of this agent gave rise to salivation and other constitutional