Biii = 11.

The element boron (L. bor(ax) + on, fr. Ar. baraqa, shine, glisten, substance from which the element first was obtained) resembles carbon very closely. It is infusible, non-volatile, insoluble, and is found sparingly in nature. Occurs as either boric (boracic) acid or sodium borate (borax). Chiefly in Italy and California.

Acidum Boricum. Boric Acid, H3BO3. - (Syn., Acid. Bor., Boracic Acid, Acidum Boracicum; Fr. Acide borique (crystallise); Ger. Bor-saure.)

Manufacture: Occurs in nature free and combined, but for medicine is prepared usually by dissolving sodium borate (borax) 10 parts in water 24, filtering while hot and adding hydrochloric acid 6; crystallize in a cool place, wash crystals with little cold water to remove adhering acid - Na2B4O7.10H2O + 2HC1 = 4H3BO3 + 2NaCl + 5H2O; yield 5-6 parts. Sulphuric acid may be used for hydrochloric, but adheres more persistently to the boric acid, necessitating two or three recrys-tallizatlons. It is in transparent, colorless scales (pearly lustre), 6sided, triclinic crystals, white, bulky powder, slightly unctuous to touch; odorless; faintly bitter taste; permanent, soluble in water (18), boiling water (4), alcohol (18), boiling alcohol (6), glycerin (4); aqueous solution (1 in 50) slightly acid; contains 99.5 p. c. of H3BO3. Tests: 1. Volatilizes from boiling aqueous or alcoholic solution; dissolve in alcohol, glycerin - green flame. 2. Aqueous solution + little hydrochloric acid T. S. - turns turmeric paper reddish-brown on drying, changed to greenish-black by ammonia water. 3. At 100° C. (212° F.) loses H2O, forming metaboric acid (hydrogen metaborate, HBO2), which slowly volatilizes; at 160° C. (320° F.) fuses to glassy mass (tetraboric, pyroboric acid, hydrogen tetraborate, H2B4O7); at higher temperature fused mass swells, loses all water and becomes boron trioxide, B2O3, which fuses into transparent, non-volatile, hygroscopic mass. Impurities: Heavy metals, arsenic, etc. Dose, gr. 5-30 (.3-2 Gm.).

Preparations. - 1. Glyceritum Boroglycerini. Glycerite of Boro-glycerin. (Syn., Glycer. Boroglyc, Glycerite of Glyceryl Borate, Solution of Boroglyceride; Br. Glycerinum Acidi Borici; Fr. Glycere (Solute) de Boroglyceride; Ger. Boroglyceridlosung.)

Manufacture: 50 p. c. (glyceryl borate). Heat glycerin 46 Gm. to 150° C. (302° F.), add in portions, constantly stirring, boric acid 31 Gm., when dissolved, evaporate to 50 Gm., frequently stirring and breaking surface film, add glycerin 50 Gm., mix thoroughly - antiseptic. Should be kept in tightly-stoppered bottles.

2. Unguentum Acidi Borici. Ointment of Boric Acid. (Syn., Ung. Acid. Bor.; Fr. Onguent d'Acide borique; Ger. Borsalbe.)

Manufacture: 10 p. c. Melt paraffin 5 Gm., add white petrolatum 85 Gm., heat gently until liquefied, add hot liquid to boric acid 10 Gm., contained in a warm mortar, triturating thoroughly, stir until congealed.

Unoff. Preps.: Solutions, 1-5 p. c. Suppositoria Boroglycerini, each - glycerite of boroglycerin 1.25 Gm., glycerinated gelatin 1.67, glycerin 1.25.

Properties. - Antiseptic, poisonous.

Uses. - Dyspepsia, restores acidity to ammoniacal urine; externally - conjunctivitis, aphthous ulcers of mouth, diphtheria, vaginitis, otor-rhoea, pharyngitis, burns, ulcers, boils, pruritus, urticaria, eczema, psoriasis, catarrhs, cystitis, gonorrhoea, erysipelas, tinea, fetid feet. Trituration with ether facilitates its powdering.

Fig. 443.   Boric acid crystal.

Fig. 443. - Boric acid crystal.