That the weight of the beaker glass and the water should be previously determined, goes without saying. As mentioned above, the yellow phosphorus, even under water, emits a faint, whitish light, which is supposed to be due to an evolution of minute quantities of phosphine, PH,, and the immediate decomposition of same with the evolution of a microscopic flame. The red phosphorus is prepared by heating the yellow variety to 300° C. in closed tubes, in an atmosphere of nitrogen. This product is a dark-red powder, perfectly stable in air, and comparatively non-toxic. Red phosphorus is largely used in place of yellow phosphorus in the manufacture of matches and the like, and its use has greatly lessened the dangers of this trade. Metallic phosphorus is made by heating the red to 530° C. in vacuo. It appears in steel-like scales, and has no interest in pharmacy. Medical Properties.-Powerful nervous stimulant; a violent poison. Dose.-0.5 milligramme (grain). Antidote.-Old (ozonized) oil of turpentine. Official Preparation.-Pills of phosphorus, each containing about To grain of phosphorus (p. 324). The pharmacopoeia of 1890 also recognized: Phosphorated oil (U. S. P. 1890)-1 minim represented about grain of phosphorus. Spirit of phosphorus (U. S. P. 1890) solution of phosphorus (1.2 Gm.) in absolute alcohol (1000 Cc.). Elixir of phosphorus (U. S. P.), made from the spirit and containing about grain of phosphorus to the fluidrachm. CARBON Symbol, C. Atomic weight, approximately 12 The name of this element is derived from the word carbo, which was the Latin name for coal. Carbon is found in the free form as diamond, graphite, and coal, while its combinations are very widely distributed. For example, all organic matter contains carbon. It is also found as carbonate in several well-known minerals; thus, marble and lime-stone are calcium. carbonate, while dolomite is a mixture of calcium and magnesium carbonates. Carbon, as such, is found in three allotropic forms, they being diamond, graphite, and coal. Diamond is the crystalline form of carbon, and is found in hard, transparent masses, possessing the specific gravity 3.5 to 3.6. The proof of its being carbon pure and simple is that when ignited in a stream of oxygen it is all consumed with the exception of a trace of ash (about of 1 per cent.), forming nothing but carbon dioxide gas. Its formation from the other varieties of carbon has already been explained on p. 146. Graphite is a gray-black, soft, amorphous solid, known to all as the so-called "lead" of the pencil. It has a specific gravity of about 2.25, and is of interest because of its resistance to heat. For this reason graphite is used for making crucibles-the so-called black-lead crucibles. (See p. 81.) Coal is the impure, non-crystalline form of carbon, and can be divided into two commercial varieties, anthracite, or hard coal, bituminous, or soft coal. Coal, on being heated in retorts, gives up its volatile portion, yielding illuminating gas, ammonia, and coal-tar, while the residue is the commercial coke, which contains about 91 per cent. carbon. The great value of coal and coke as a fuel has already been touched upon on p. 68. Charcoals are more or less pure forms of amorphous carbon. CARBO LIGNI. Charcoal. Charcoal prepared from soft wood, and very finely powdered. It should be kept in well-closed vessels. A black, odorless, and tasteless powder, free from gritty matter. If 1 Gm. of Charcoal be boiled with a mixture of 3 Cc. of potassium hydroxide T.S. and 5 Cc. of water for several minutes, the filtrate should be colorless or nearly so (evidence of complete carbonization). Remarks. This is to be prepared from soft wood, very finely powdered; that prepared from willow-wood being considered best. The pharmacopoeia directs that the wood-charcoal be kept in well-closed vessels, because it readily absorbs odors. In fact, the medical value of wood-charcoal depends very largely on this property of absorbing gases, and it is for this reason that charcoal is valuable in indigestion. The process of manufacture is given on p. 847. Dose.-1 Gm. (15 grains). CARBO ANIMALIS. Animal Charcoal. Charcoal prepared from bone. Dull black, granular fragments, or a dull black powder, odorless, nearly tasteless, and insoluble in water or alcohol. When ignited, it leaves a grayish or yellowish-white ash, amounting to about 85 per cent. of the original weight of the portion taken, which should have been previously dried at 120° to 125°C. (248° to 257° F.) to a constant weight. The ash should be soluble in hydrochloric acid with the aid of heat, leaving not more than a trifling residue. If 1 Gm. of Animal Charcoal be boiled for several minutes with a mixture of 3 Cc. of potassium hydroxide T.S. and 5 Cc. of water, the filtrate should be colorless or nearly so (evidence of complete carbonization). Remarks. This form, commercially called bone-black, is prepared by the carbonization of bones, the dried bones being placed in a castiron retort and carbonized (during the process a liquid distils over which is called bone oil), and the residue in the retort is then removed and reduced to powder. This animal charcoal contains the carbon from the organic matter of the bones plus all the bone-ash, and it therefore contains a large amount of calcium phosphate. Animal charcoal is used as a decolorizer, as explained on p. 137, and the presence of calcium phosphate in the animal charcoal renders its use inadvisable in removing color from liquids containing acids, as calcium phosphate will dissolve therein. Therefore the pharmacopoeia directs the use of the second form of animal charcoal, from which bone-ash has been removed. CARBO ANIMALIS PURIFICATUS. Purified Animal Charcoal. 100 Gm. 300 Gm. Recipe.-Animal Charcoal, in No. 60 powder, one hundred grammes... Hydrochloric Acid, three hundred grammes.. By Introduce the Animal Charcoal into a capacious vessel, add two hundred grammes of Hydrochloric Acid and four hundred cubic centimeters of Boiling Water. means of a sand-bath keep the mixture gently boiling during eight hours, adding water occasionally to maintain the original volume. Then add five hundred cubic centimeters of Boiling Water, transfer the mixture to a muslin strainer, and, when the liquid has run off, return the Charcoal to the vessel. Add to it one hundred grammes of Hydrochloric Acid and two hundred cubic centimeters of Boiling Water, boil for two hours, again add five hundred cubic centimeters of Boiling Water, transfer the whole to a plain filter, and when the liquid has passed through, wash the residue with Boiling Water until the washings produce only a faint cloudiness with silver nitrate T.S. Dry the powder in a drying oven, and immediately transfer it to wellstoppered vials. A dull black powder, odorless, tasteless, and insoluble in water, alcohol, or other solvents. If 2 Gm. of the powder be ignited at a red heat with free access of air in a broad, shallow, porcelain or platinum dish it should not leave a residue weighing more than 0.08 Gm., or 4 per cent., of the original weight (limit of silicates and other fixed inorganic matter). If 1 Gm. of the powder be boiled with a mixture of 3 Cc. of potassium hydroxide T.S. and 5 Cc. of water during three minutes, the filtrate should be colorless (evidence of complete carbonization). Remarks.—This is made by digesting animal charcoal with hydrochloric acid on a sand-bath for a period of eight hours, and, after straining the liquid, returning the charcoal to the vessel. The operation is repeated with a second amount of hydrochloric acid, and the digestion continued for two hours. Finally, the acid is drained off, the charcoal freed from all traces of acid by washing with water, and the product dried. The acid effects the solution of the bone-ash by converting it into soluble acid calcium phosphate, described in the manufacture of phosphorus (p. 404). Purified animal charcoal is an excellent decolorizer, and should always be used by the pharmacist in preference to the crude product. The removing of color by means of purified animal charcoal is done by macerating the liquid with the charcoal for several hours, and finally filtering. It is well to remember that animal charcoal not only absorbs the color from a solution, but also absorbs some active plant principles, such as alkaloids and glucosides. Therefore, care should be taken to avoid the loss of active ingredients by too long contact with the charcoal. Lamp-black is carbon produced by burning rosin, petroleum, or natural gas in a limited amount of air, and collecting the "soot" thus produced. BORON Symbol, B. Atomic weight, approximately 11 The word boron comes from boraq, which was the Arabic name for borax. The element was first isolated by Gay Lussac and Thenard in 1808. Boron occurs in nature in the form of boric acid, sodium borate, and boracite, the latter being a magnesium borate. It is found in two allotropic forms, crystalline and amorphous. Its compounds with hydrogen and oxygen yield several acids, such as boric, metaboric, and pyroboric acids. Boron is not official, but it is found in official bodies-boric acid and borax. It should contain not less than 99.8 per cent. of pure Boric Acid [B(OH),]. Transparent, colorless scales, of a somewhat pearly lustre, or six-sided, triclinic crystals, or a light, white, very fine powder, slightly unctuous to the touch; odorless, having a faintly bitter taste, and permanent in the air. Boric Acid is soluble in 18 parts of water, 15.3 parts of alcohol, and 4.6 parts of glycerin at 25° C. (77° F.); in 3 parts of boiling water and 4.3 parts of boiling alcohol. The addition of hydrochloric acid decreases its solubility in water. When heated to 100° C. (212° F.), Boric Acid loses water, forming metaboric acid (HBO), which slowly volatilizes at that temperature. Heated to 160° C. (320° F.), it fuses to a glassy mass of tetraboric (or pyroboric) acid (H,B,O,); at a higher temperature the fused mass swells up, loses all of its water, and becomes boron trioxide (B,O,), which fuses into a transparent, hygroscopic, non-volatile mass. Boric Acid readily volatilizes from a boiling aqueous solution. Tests for Identity.-Green flame. See Part V. Turns turmeric paper brown. See Part V. Impurities. Sulphates, chlorides, calcium, magnesium, heavy metals, arsenic, and not more than trace of iron. Details of each test in Part V. Assay.-Details in Part V. Remarks. The formula of this compound, commonly called boracic acid, has already been discussed (p. 373), so here it is only necessary to emphasize the fact that boric acid is only true official ortho-acid. Boric acid is found in the free form in lagoons in volcanic regions of Tuscany, the water being evaporated with the aid of the jets of steam emitted from the volcanic soil. It is now made in large quantities in this country from native borax (p. 459) by treating it with hydrochloric acid, the equation being: Na,B,0,0, + 2HCl = 2NaCl + 4H,BO2 + 5H2O. Boric acid is found in the form of crystalline micaceous scales, which possess a peculiar unctuous feeling. Boric acid is volatile, but more freely, however, in the vapor of water than if heated by itself. Boric acid is now popular in the form of an impalpable powder, and the preparation of this caused considerable annoyance on account of the slipperiness of the crystals, until it was found that trituration of boric acid in a warmed mortar or mill brings the desired results. The two tests of boric acid are, first, the fact that an alcoholic solution burns with a flame enveloped with a green mantle, and, secondly, its property of changing yellow tumeric paper to a reddish brown. SILICON Symbol, Si. Atomic weight, approximately 28 The word silicon is derived from silica, or sand, which in turn is derived from the Latin silex, which means flint. The element was isolated by Berzelius in 1810. Silicon is the most abundant element on the earth's surface. Thus, quartz, sand, opal, agate, and infusorial earth are more or less pure silicic oxide. Silicon is another element appearing in two allotropic forms, crystalline and amorphous. None of the forms of silicon is of sufficient pharmaceutic interest to merit more than passing notice. Silicon, as shown on p. 369, yields one oxide, SiO.. The hypothetic combinations of this, with water, are silicic acids, H.SiO, and HSiO, and the salts of these acids are the ordinary silicates. Silicates of complex formulas, such as orthoclas, K,AISO16 are known. Glass is a combination of the silicates of sodium or potassium with lead or cal The test for soluble silicates is that they yield with acids a white gelatinous precipitate of orthosilicic acid, H,SiO.. The silicates other than those of the alkalies are insoluble in all acids, even the strongest, except hydrofluoric acid. In order to obtain these silicates in soluble form it is necessary to fuse them with a mixture of sodium and potassium carbonates, whereby silicates of sodium and potassium are formed. The only official preparation of silicon in the present pharmacopoeia is kaolin. This will be considered among the compounds of aluminum (p. 539). Liquor sodii silicatis, which was official in the pharmacopoeia of 1890, is discussed on p. 474. CHAPTER XXIV THE ACIDS AN acid is a substance which changes blue litmus-paper red, and combines with bases to form salts. The substances answering this definition are both inorganic and organic, and among the inorganic acids, as already mentioned, are found both binary or ternary compounds. The binary compounds are the four bodies, hydrochloric acid, HCl, hydrobromic acid, HBr, hydriodic acid, HI, and hydrofluoric acid, HFl. These four are called haloid acids, because derived from the four halogen elements. Three of these haloid acid recognized by the pharmacopoeia either alone or in pharmaceutic preparations. are Organic acids consist of carbon radicals combined with the group carboxyl, COOH. These will be discussed under their proper grouping in Part IV. The inorganic acids are, with the exception of the haloid acids just mentioned, hydrates of the negative elements. Acids may be solids, liquids, or gases; in fact, all the members of this large group have little in common save their acid action on litmus-paper and their ability to form salts with the alkalies. In this chapter we will discuss all the official inorganic acids except boric acid, chromic acid, and arsenous acid, the three being considered under the elements from which derived. All those considered in this chapter are liquids, and are commercially called the heavy acids, because their specific gravity is greater than water. These acids are usually in the concentrated form, and decidedly caustic. Hence in handling them great care must be taken to avoid bringing them in contact with delicate substances. If, in handling, they are spattered on the skin, they should be immediately washed off; if the area of burn is considerable, it should be covered with emollients of mildly alkaline character, such as lime liniment or sodium bicarbonate. Their active character prevents their ordinary storage in wood or metal, although it might be of interest to mention that sulphuric acid in concentrated form can be safely stored in iron tanks, that acid attacking iron only when diluted. În pharmacy, however, such acids must be handled entirely in glass or porcelain, and in purchasing quantities of the same they are usually |