during its solution, in which case it should be applied as soon as the salt is dissolved, or for the stimulus of the salt, on which principle it acts as a powerful discutient in indolent tumours (_Form. 146._) It is also an ingredient in a very useful plaster, in which it undergoes chemical decomposition; this plaster consists of _Soap_ ℥j, _lead plaster_, ʒij, liquified together, to which, when nearly cold, are added of _muriate of ammonia_ finely powdered ʒss. The alkali of the soap enters into combination with the muriatic acid of the muriate of ammonia, and forms thereby muriate of potass, or soda, and ammoniacal gas (on which the virtue of the plaster depends) is slowly but abundantly liberated, acting as a powerful stimulant and rubefacient: it should be applied immediately after it is formed, and be renewed every twenty-four hours, otherwise the intention is lost; (_Pharmacopœia Chirurgica._) I have often applied this plaster with evident advantage to the chest in pulmonary affections, and I wish to recommend it to the attention of practitioners. It is very useful also in that rheumatic affection of the muscles of the chest, which is so frequently met with in persons in advanced life; during the last winter I was consulted in two cases where the distress after exercise was so considerable as to resemble angina pectoris. OFFICINAL PREPARATIONS. _Ammoniæ Sub-carbonas_ (=I=). L.E.D. _Liquor: Ammoniæ_ (=K=). L. _Aqua Ammoniæ._ E.D. _Hydrarg: præcip: alb:_ (=I=). L. _Alcohol Ammoniatum_, (=I=). E.D. _Ferrum Ammoniat:_ (=G=). L.E.D. ADULTERATIONS. This salt, if pure, may be entirely volatilized by a low heat; the _sulphate of ammonia_ however, as it is also volatile, cannot be discovered except by the muriate of baryta, which will indicate its presence by a copious precipitate. AMYGDALÆ DULCES. {Varieties of “Amygdalus Communis.” AMYGDALÆ AMARÆ. {Sweet and Bitter Almonds.