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ELEMENTS OF MATERIA MEDICA.
the present preparation has been introduced into the Pharmacopoeia as asuccedaneum for it. In preceding editions of the London Pharma-copoeia it was termed pulvis antimonialis (antimonial powder) ; but in theedition for 1830 this name was unnecessarily (as I conceive) altered topulvis antimonii compositus. In the Edinburgh Pharmacopoeia it isdenominated oocydum antimonii cum calcis phosphate; in the French Codex , pulvis cum stibio compositus.
Preparation.— In the London Pharmacopoeia it is directed to be pre-pared by throwing a mixture of one pound of sesquisulphuret of anti-mony in powder, and two pounds of hartshorn shavings, into a cruciblered hot in the fire, and stirring constantly until vapour no longer arises.Rub that which remains to powder, and put it into a proper crucible.Then apply fire, and increase it gradually, that it may be red hot for twohours. Rub the residue to a very fine powder.
The process of the Dublin Pharmacopoeia is analogous to the above,as are also those of the Edinburgh Pharmacopoeia and French Codex ,with the exception that in the two latter works equal parts of sesquisul-phuret and hartshorn shavings are used.
Manufacturers usually substitute bone sawdust for hartshornshavings.
The following is the theory of the process: the gelatinous matter ofthe horn (or bones) is decomposed and burned off, leaving behind theearthy matter (sub- or •§-, phosphate of lime, with a little calcareouscarbonate). The sulphur of the sesquisulphuret is expelled in the formof sulphurous acid, while the antimony attracts oxygen from the air,forming antimonious acid, and a variable quantity of sesquioxide of anti-mony. By the subsequent heating the sesquioxide is, for the most part,converted into antimonious acid ; but one portion is usually left unchanged,while another is volatilized. The carbonate of lime of the hom is decom-posed by the united agencies of heat and antimonious acid: carbonic acidis expelled, and a small quantity of antimonite of lime formed. The sidesof the crucible in which the second stage of the process has been con-ducted, is found, at the end of the operation, to be lined with a yellowglaze, and frequently with yellow crystals of sesquioxide.
Properties. —Antimonial powder is white, gritty, tasteless, and odour-less. Boiling water extracts the antimonite (and superphosphate, Dr.Maclagan) of lime: the liquid becomes cloudy on cooling. Hydrochloricacid, digested in the residue, dissolves the subphosphate of lime, all thesesquioxide of antimony, and a portion of the antimonious acid.
Characteristics. —The solution obtained by boiling antimonial pow-der in distilled water occasions white precipitates, soluble in nitric acid,with oxalate of ammonia, nitrate of silver, and acetate of lead: hydro-sulphuric acid gas transmitted through the solution, produces an orangered precipitate. If the portions of antimonial powder not dissolved bydistilled water be digested in boiling liquid hydrochloric acid, a solutionis obtained, which, on the addition of distilled water, becomes turbid,and deposits a white powder: at least 1 have found this to take placewith several samples of antimonial powder which I have examined, andthe same is noticed by Dr. Barker ( Observations on the Dublin Pharma-copoeia, 204); but neither Mr. Phillips {Ann. Phil. iv. N. S. 266) nor Dr.Maclagan ( Edinburgh Med . Sf Surg. Journ. No. 135) have observed it.Ilydrosulphuric acid gas, transmitted through the hydrochloric solution,