GUA′IACIN. Syn. Guaiacic acid, Pure guaiacum resin. A substance having the nature of an acid, discovered by Trommsdorff in the wood and bark of Guaiacum officinale.
Prep. The tincture of guaiacum is treated with hydrate of lime, and the guaiacate of lime thus formed is decomposed with dilute sulphuric acid; it is purified by dissolving it in alcohol.
Prop., &c. Insoluble in water; soluble in alcohol and ether; it unites with the caustic alkalies, forming alkaline guaiacates (guaiacum soaps); air and light turn it green; gluten, mucilage of gum Arabic, &c., turn it blue; nitric acid and chlorine turn it successively green, blue, and brown; tincture of guaiacin, added to hydrocyanic acid and sulphate of copper, produces an intense blue colour. (Pagenstecher.) A delicate photographic paper may be formed by washing unsized paper with an alcoholic solution of guaiacum resin, and afterwards with one of neutral acetate of lead. (Johnston.)
GUA′IACUM. Syn. Guaiac, Gum guaiacum, Guaiacum resin; Guaiacum (Ph. L.), (Guaiac resin, Guaiaca resina, B. P.). The resin prepared by means of fire from the wood of Guaiacum officinale, by natural exudation, by incision, or by heat. (B. P.) This substance is often adulterated. When pure, its “fresh fracture is red, slowly passing to green; the tincture slowly strikes a lively blue colour on the inner surface of a thin paring of raw potato.” (B. P.) Adulteration with resin may be generally discovered by the odour evolved when the guaiacum is heated. An alcoholic tincture of guaiacum, rendered milky with water, recovers its transparency on the addition of caustic potassa in excess; but this is not the case when resin is present.
Guaiacum is stimulant, sudorific, and alterative.—Dose, 10 to 30 gr., either in powder or pills; in chronic rheumatism, gout, obstinate chronic skin disease, scrofula, syphilis, &c. It forms the active ingredient of the once celebrated ‘Chelsea Pensioner,’ and the ‘GOUT SPECIFIC’ of Mr Emerigon. The latter was made by digesting 2 oz. of guaiacum resin in 48 fl. oz. of rum, for seven or eight days. The dose of this was a table-spoonful every morning, fasting, for a twelvemonth. Its other properties are similar to those of GUAIACIN, but are less marked. Sp. gr. 1·20 to 1·22.
Guaiacum Wood. Syn. Lignum vitæ, Guaiaci lignum (Ph. L.), L. The wood of Guaiacum officinale. This is employed under the form of shavings, raspings, and sawdust, in decoctions only. See Decoction and Balsam.
GUA′NO. Syn. Huanho, Peruv. This substance, now so extensively used in agriculture, is the partially decomposed excrement of certain aquatic birds, chiefly the common penguin, which congregate in countless numbers on the barren and uninhabited islets and rocks on the western coasts of South America and the coasts of Africa. It abounds in ammonia and the phosphates, and is undoubtedly the richest natural manure known. Under judicious application the increase of the crops of grain, turnips, potatoes, and grass consequent upon its use is said to be about 33%. “Guano is peculiarly adapted to horticultural and floricultural improvement, by its relative cleanliness and facility of application.” (Ure.)
“According to Denham Smith,[339] South American guano, as imported, presents itself in three distinct states, the three varieties being not unfrequently mixed together in the same bag; the first variety is damp and pulverulent; the second exists as large concretions, presenting various aspects when broken; the third is heavy and crystalline, and is termed ‘stone’ by the labourers. These three varieties differ widely in composition, as the following comprehensive analysis, by Smith, will show:—
[339] ‘Proceedings of the Chem. Soc.,’ vol. ii.
| Soluble in Water. | |||
| I. Pulverulent. | II. Concrete. | III. Saline. | |
| Water | 222·00 | 250·00 | 97·00 |
| Chloride of ammonium | 25·50 | — | 30·30 |
| Sulphate of potash | 80·00 | — | — |
| Sulphate soda | traces | 258·44 | 191·77 |
| Oxalate of ammonia | 74·00 | 93·90 | — |
| Oxalate soda | — | — | 105·63 |
| Phosphate of ammonia | 63·30 | 61·24 | — |
| Phosphate potash | — | 77·32 | 49·47 |
| Phosphate soda | 1·20 | — | 3·60 |
| Chloride of sodium | — | 29·22 | 286·31 |
| Chloride of potassium | — | — | 41·63 |
| Organic matter | 15·00 | 6·68 | 25·53 |
| Urate of ammonia | 154·18 | — | — |
| Uric acid | 25·16 | — | — |
| Ammonia phosphate of magnesia | 5·64 | 7·84 | 1·33 |
| Animal matter | 11·80 | 8·60 | 7·56 |
| Insoluble in Water. | |||
| I. Pulverulent. | II. Concrete. | III. Saline. | |
| Oxalate of lime | 25·60 | 109·58 | — |
| Phosphate of lime | 199·30 | 62·70 | 132·23 |
| Phosphate of magnesia | 20·30 | 8·74 | 25·80 |
| Oxide of iron | — | — | 1·56 |
| Humus and organic matters | 60·92 | 8·00 | 18·36 |
| Sand | 15·60 | 7·20 | 4·20 |
| Loss | ·50 | 10·54 | 7·78 |
| ——— | ——— | ——— | |
| 1000·00 | 1000·00 | 1000·00 | |