PHARMACY. 



submuriate of antimony and of phosphate 

 of lime in the smallest possible quantity 

 of muriatic acid, and then pouring this 

 solution gradually into water sufficient- 

 ly alkalized with ammonia. For the rea- 

 son mentioned in the preceding article, it 

 is absolutely necessary that the muriatic 

 solution be poured into the alkaline liquor. 

 By an opposite mode of procedure, the 

 precipitate would contain more antimony 

 at first, and towards the end the phos- 

 phate of lime would be predominant, and 

 the antimony would be partly in the state 

 of a submuriate. The phosphate of lime 

 is most conveniently obtained pure by 

 dissolving calcined bone in muriatic acid, 

 and by precipitating it by ammonia. If 

 the ammonia be quite free from carbonic 

 acid, no muriate of lime is decomposed. 

 M. Chenevix also found that his precipi- 

 tate is entirely soluble in every acid which 

 can dissolve either phosphate of lime or 

 oxide of antimony separately, and that 

 about 0.28 of James's powder, and at an 

 average 0.44 of the pulvis antimonialis of 

 the London Pharmacopoeia, resist the ac- 

 tion of every acid. 



CLASS VI. QleaFixata. FIXED OILS. 



These oils are improperly denominated 

 expressed, which is their usual characte- 

 ristic name, as in some instances they are 

 obtained without expression, and in other 

 instances expression is employed to ob- 

 tain volatile oils. The Edinburgh college 

 have therefore distinguished these differ- 

 ent classes of oils by the terms fixed and 

 volatile, which accurately characterize 

 them. 



Fixed oil is formed in no other part of 

 vegetables than in their seeds. Some- 

 times, although very rarely, it is contain- 

 ed in the parenchyma of the fruit. Of 

 this, the best known example is the olive. 

 But it is most commonly found in the 

 seeds of dicotyledonous vegetables, some- 

 times also in the fruit of monocotyledo- 

 nous plants, as the cocos butyracea. It 

 has various degrees of consistency, from 

 the tallow of the croton sebiferum of Chi- 

 na, and the butter of the butter-tree of 

 Africa, to the fluidity of olive oil. 



Fixed oils are either, 1. Fat, easily con- 

 gealed, and not inflammable by nitric 

 acid, oil of olives, almonds, rapeseed, 

 and ben. 2. Drying, not congealable, in- 

 flammable by nitric acid, oil of linseed, 

 nut, and poppy. 3. Concrete oils, palm 

 oil, Sec. 



Fixed oil is separated from fruits and 

 seds which contain it, either by expres- 



VOL, V, 



sion or decoction. Heit, by rendering tha 

 oil more limpid, incrc -s very much the 

 quantity obtained by expression ; but as 

 it renders it less bland, and more apt to 

 becomt rancid, heal is not used in the 

 preparation of oils which are to be em- 

 ployed in medicine. When obtained by 

 expression, oils often contain a mixture 

 of mucilage, starch, and colouring mat* 

 ter; but part of these separate in course 

 of time, and fall to the bottom. When 

 oils become rancid, they are no longer 

 fit for internal use, but are then said to 

 effect the killing of quick-silver, as it is 

 calltd, more quickly. Decoction is prin- 

 cipally used for the extraction of the 

 viscid and consistent oils, which are melt- 

 ed out by the heat of the boiling water^ 

 and rise to its surface. 



Those who prepare large quantities ot 

 the oil of almonds, blanch them, by steep- 

 ing them in very hot water, which causes 

 their epidermis to swell, and separate 

 easily. After they peel them, they dry 

 them in a stove, then grind them in a 

 mill like a coffee mill, and lastly, express 

 the oil from the paste inclosed in a hemp- 

 en bag. By blanching the almonds, the 

 paste which remains within the bag is sold 

 with greater advantage to the perfumers, 

 and the oil obtained is perfectly colour- 

 less. But the heat employed disposes 

 the oil to become rancid, and the colour 

 the oil acquires from the epidermis does 

 not injure its qualities. For pharmaceu- 

 tical use, therefore, the oil should not be 

 expressed from blanched almonds, but 

 merely rubbed in a piece of coarse linen, 

 to separate the brown powder adhering 

 to the epidermis as much as possible. 

 Sixteen ounces of sweet almonds com- 

 monly give five ounces and a half of oil, 

 Bitter almonds afford the same propor- 

 tions, but the oil has a pleasant bitter 

 taste. 



In this manner are to be expressed, 



Oleum amygdalae, almond oil, from the 

 kernel. 



Oleum lini, linseed oil from the bruised 

 seeds. 



Oleum ricini, castor oil, from the seedd 

 previously decorticated. 



Oleum sinapeos, oil of mustard, from 

 the bruised seeds. 



CLASS VII. Aqua Distillate. DISTILLED 

 WATERS. 



Substances which differ in volatility ^ 

 may be separated from each other by 

 applying a degree of heat capable of con- 

 verting the most volatile into vapour, and 



Dd 



