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ammonia produces with it a similar bluisli-white precipitate, but an exccss redjs-solves it, forming a deep blue liquid (cuprate of ammonia:) ferrocyanide of po-tassium occasions in it a reddish-brown precipitate (ferrocyanide of copper;) thehydrosulphurets throw down a precipitate (mlphuret of copper;) and, lastly,a polished iron plate plunged, into the liquid, becomes coated with metalliccopper.

Physiological Effects. «. °* Mctainc copper.—Metallic copper appears toproduce no pernicious effects when taken internally, so long as it retains its me-tallic State, as many cases are recorded where coins of this metal have been swal-lowed, and retained for a considerable time, without any ill effects arising; andDrouard [Exper. et Observ. sur FEmpoisonnern. par POxide de Cuivre. Paris,1802.) gave as much as an ounce of finely-powdered copper to dogs of differentages and sizes, but none of them experienced any inconvenience therefrom.

Notwithstanding these facts, however, various effects have been attributed toit. Thus, Cothenius (Voigtel, Mrzniemittellehre.) says, copper filings operateby stool, urine, and saliva; and the l'ate Professor Barton (Chapman, Eiern, ofTherup. ii. 457.) was accustomed to relate an instance of a child, who, havingswallowed a cent, continued for some time to discharge several pints of saliva.Lastly, Portal (Orfila, Toxicol. Gen.) mentions a case in which copper filings,incorporated with crumb of bread, acted powerfully on the System. I have nodoubt but that the effects here mentioncd arose from the oxidation of the metalby the acids of the alimentary canal.

ß. of tue Cupreows Compounds.—Most, if not all, the preparations of copperare poisonous in large doses. The sulphuret and ferrocyanide are doubtful ex-ceptions to this Statement. If the cupreous preparations be used in vcry smalldoses, they sometimes give relief in certain diseases (principnlly of the nervousSystem,) without obviously disordering the functions; in other words, in theseinstances the only apparent effect is the modification observed in the morbid con-dition. These are cases in which these preparations have been termed lonic,anlispasmodic, or aiterative, according to the nature of the disease; thus, in aguethey have been termed tonic, in epilepsy antispasmodic, in dropsy aiterative.The beneficial Operation is presumed to be owing to some influence exerted bythe remedy over the nervous System. The effects produccd by the long-con-tinued use of small doses of the preparations of copper have not been satisfactorilydetermined; they are Said to be various affections of the nervous System (such ascramps or paralysis,) alteration of the colour of the skin, chronic inflammation ofthe respiratory and digestive apparatus, slow fever, and wasting of the body.These Symptoms constitute what has been termed slow, or chronic poisoning bycopper. The smelters and workers in copper do not suffer from the vapour oremanation of this metal, as the workmen employed in the preparation of mer-cury, of arsenic, or of lead do, from the vapours of these metals: this, indeed,might be expected, when we considcr how much more volatile the latter and theirpreparations are, than copper and its Compounds. In larger, or füll medicinaldoses, these remedies act as emetics, exciting specdy vomiting, with less nauseathan tartar emetic produces. In still larger quantities, these bodies act as poi-sons, giving rise to gastro-intestinal inflammation, and disordering the functionsof the nervous System (especially the cerebro-spinal portion,) constituting acute,poisonin^ by copper. The usual Symptoms are, a coppery taste, eructations,violent vomiting and purging, griping pains, cramps in the legs and thighs, head-ach, giddiness, convulsions, and insensibility: jaundice is occasionally observed.In some cases the cerebro-spinal Symptoms precede those which indicalc inflam-mation of the alimentary canal. In experiments made on animals, it has beenobserved that death was sometimes produced without any marks of local irri-tation; the Symptoms being those indicative of a disordered condition of the ner-vous System. By some toxicologists these preparations are ranked amoiig the