TANNIC ACID, or TANNEY. Under these synonymous terms, chemists include a number of solid non-nitrogenous substances, consisting of carbon, hydrogen, and oxy gen, some of which are crystalline, and others amorphous, and possessing no smell, but a well-marked astringent taste. They are soluble in water and alcohol, the solutions being acid, and yielding precipitates with most metallic oxides. A solution of gelatine is also precipitated by a solution of any of the tannic acids, and the gelatinous tissue in raw hides is by an analogous process converted into leather. See GALLOTANNIC ACID. None of these acids are volatile; and when exposed to the action of heat, they decompose, and yield the so-called pyro.acids. The persalts of iron yield bluish-black or green precipitates with the tannic acids.
The members of this group are widely diffused throughout the vegetable kingdom. "The bark and leaves of most forest trees, such as the oak, the elm, the willow, the horse-chestnut, and the pine—and of many fruit trees, such as the pear and plum, con tain tannin in notable quantity. The wood and bark of many shrubs, such • as the sumach and whortleberry, and the roots of the tormentilla and bistort, are also power fully astringent, owing to the presence of One of the forms of tannin. Coffee and tea, as well as Paraguay tea, likewise contain a modification of this principle. All these bodies, except coffee, precipitate the persalts of iron of a bluish.black color; or, if a free acid be present, the solution assumes a dark-green color."—Miller's Organic Chem istry, 2d ed. p. 400. The variety of tannin, or tannic acid, occurring in catechu and kino, produces a green precipitate with the persalts of iron; while that occurring in matricaria, rhatany, and the common nettle, a gray precipitate. The princi pal members of this group are-1. Gallotannic acid, or tannic acid, C.411220.4 (in the ordi nary acceptation of the word), which is mainly obtained from the gall-nut, and has been described in a special article; 2. Moritannzc acid, 20, obtained from fustic (moms tinctoria); 3. Quinotannic acid, C2EniaCii, obtained from cinchona bark; 4. Quercitannic acid, from oak bark ; 5. Mimotannic acid, C6 II 0
4 24 24, from catechu; and 6. Kinotannic acid, from kino; to which some chemists add a variety occurring in coffeE.. and Paraguay tea, to which the term caffotannic acid is given.
TANSY, a genus of plants of the natural order c,ompositcs, sub-ordes corymbifcrce, allied to artemisia (q.v.), and having hemispherical heads of flowers, with the florets all tabular, the receptacle naked, the pappus a slight membranous border. The species are pretty numerous, and are natives of the temperate parts of the old world. COMNON TANSY (T. ruigare) is a native of Britain and of continental Europe, growing in fields and by roadsides, river-banks, etc. It has long been generally cul tivated in gardens. It is now naturalized, and pretty common in many parts of North America. It is a perennial, from two to four feet high, with great abundance of deep green, bipinnatifid, inciso-serrate leaves; the flowers in terminal corymbs, yellow, and rather small. The leaves and flowers have a strong aromatic smell and a bitter taste. The young leaves are used for flavoring puddings, cakes, omelets, etc. The plant it also tonic and anthelmintic, and tansy tea is an old popular medicine. Some curious old customs still linger in many parts of England connected with the use of tansy cakes and tansy puddings at Easter, which was originally intended to represent the use of bitter herbs at the paschal feast. In some parishes of the counties of Devon and Dorset the clerk carries round to every house a few white tansy cakes as an Easter offering after divine service on Good Friday, and receives a gratuity from each householder. In former times both ecclesiastics and lairs played at ball in the churches for tansy cake at Easter-tide. The highest dignitaries took part in this, and began the ball-playing, which went on during the antiphone, and was accompanied with dancing. After the ball-play ing was over, all retired for refreshments; and a gammon of bacon was a standard dish, to signify abhorrence of the Jews. A tansy pudding was an essential part of the feast. —See Chambers's Book of Days.