There are three definite compounds of antimony and oxygen, of which one only is ranked as an oxide, and is capable of acting as a base; the others having acid properties. it is at present generally considered by chemists as a teroxide; but I prefer the simple name above given for a medicinal title, as it is sufficiently expressive, and not liable to be mistaken, and is, besides, recognized in our officinal code. The compounds with acid properties are denominated respectively antimo-nious and antimonic acids. Several preparations, at one time officinal, contain oxide of antimony as their prominent ingredient, of which the powder of Algaroth or oxychloride is one, and the antimonial powder or compound powder of antimony, of the former British Pharmacopoeias, is another. The pure oxide, with the name at the head of this article, is now recognized in the U. S. Pharmacopoeia, which directs it to be prepared in the following manner. A terchloride of antimony is first made by digesting the tersulphuret of antimony with muriatic acid The hydrogen of the acid and the sulphur of the antimony escape in the form of sulphuretted hydrogen, and the chlorine and antimony unite to produce the terchloride, which is held in very concentrated solution. A little nitric acid is added to improve the resulting preparation, but is not essential to the process. The strong solution of the chloride thus obtained is then thrown into water, by which a precipitate is produced. A portion of the water gives its oxygen to a portion of the antimony of the terchloride forming teroxide of antimony, and the separated hydrogen and chlorine combine to form muriatic acid. The oxide thus formed combines with the undecomposed chloride, and the two are thrown down thus combined, constituting the powder of Algaroth, or oxychloride of antimony. This is then washed with an alkaline solution, by which the portion of chloride is converted into oxide. When pure, the oxide of antimony is a white powder becoming yellowish by heat, inodorous, tasteless, and insoluble in water. Exposed to heat, with the access of air, it is converted into antimonious acid by the absorption of oxygen. But the preparation most employed is either the secret empirical compound sold in England under the name of James's powder, or the antimonial powder above referred to, which is made in imitation of it. The dose of the oxide of antimony is from one to three grains, repeated at intervals of from one to four hours. it is best, however, not to give more than one grain as a commencing dose, which may be increased, if necessary, until its effects are obtained.