Vapour of Sulphurous Acid. Syn. Vapor acidi sulphurosi. (St Th. Hosp.) Sulphurous acid, 15 minims; water, 1 oz. For spray inhalation. Stimulant and antiseptic.
Vapour of Thymol. Syn. Vapor thymolis. Thymol, 6 gr.; rectified spirit, 1 dr.; light carbonate of magnesia, 3 gr.; water, 1 oz. 1 dr. to 1 pint of water at 140° F. for each inhalation. In pharyngitis and laryngitis when associated with exanthemata.
VARICOSE VEINS. See Varix.
VARIX. The permanent unequal dilation of a vein or veins, which are then said to be ‘varicose.’ It is known by the presence of a soft tumour, which does not pulsate, and often assumes a serpentine figure. Varicose veins of the groin and scrotum generally form a collection of knots. The treatment consists of cold applications, and pressure from bandages. Some cases are relieved by ligature. When occurring in the legs, much standing or walking should be avoided, and the use of the elastic stockings made for the purpose will be proper.
VAR′NISH. Syn. Vernis, Fr. Any liquid matter, which, when applied to the surface of a solid body, becomes dry, and forms a
hard glossy coating, impervious to air and moisture.
Varnishes are commonly divided into two classes—FAT or OIL VARNISHES and SPIRIT VARNISHES. The fixed or volatile oils, or mixtures of them, are used as vehicles or solvents in the former, and concentrated alcohol in the latter.[254] The sp. gr. of alcohol for the purpose of making varnishes should not be more than ·8156 (= 67 o. p.), and it should be preferably chosen of even greater strength. A little camphor is often dissolved in it, to increase its solvent power. The oil of turpentine, which is the essential oil chiefly employed for varnishes, should be pure and colourless. Pale drying linseed oil is the fixed oil generally used; but poppy oil and nut oil are also occasionally employed. Among the substances which are dissolved in the above menstrua are—amber, animé, copal, elemi, lac, mastic, and sandarach, to impart body and lustre; benzoin, on account of its agreeable odour; annotta, gamboge, saffron, socotrine aloes, and turmeric, to give a yellow colour; dragon’s blood and red sandal wood, to give a red tinge; asphaltum, to give a black colour and body; and caoutchouc to impart toughness and elasticity.
[254] Methylated spirit is now generally used for making spirit varnishes, in place of duty-paid alcohol.
In the preparation of spirit varnishes care should be taken to prevent the evaporation of the alcohol as much as possible, and also to preserve the portion that evaporates. On the large scale, a common still may be advantageously employed; the head being furnished with a stuffing-box, to permit of the passage of a vertical rod, connected with a stirrer at one end and a working handle at the other. The gum and spirit being introduced, the head of the still closely fitted on and luted, and the connection made with a proper refrigerator, heat (preferably that of steam or a water bath) should be applied, and the spirit brought to a gentle boil, after which it should be partially withdrawn, and agitation continued until the gum is dissolved. The spirit which has distilled over should be then added to the varnish, and after thorough admixture the whole should be run off, as rapidly as possible, through a silk-gauze sieve, into stone jars, which should be immediately corked down, and set aside to clarify. On the small scale, spirit varnishes are best made by maceration in closed bottles or tin cans, either in the cold or by the heat of a water bath. In order to prevent the agglutination of the resin, it is often advantageously mixed with clean siliceous sand or pounded glass, by which the surface is much increased, and the solvent power of the menstruum greatly promoted.
To ensure the excellence of oil varnishes, one of the most important points is the use of good drying oil. Linseed oil for this purpose should be very pale, perfectly limpid or transparent, scarcely odorous, and mellow and sweet to the