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tannin Chem.|ˈtænɪn|
[a. F. tanin, ‘le principe tannant’ (1798 Proust in Ann. de Chimie XXV. 225), f. tan tan n.1 + -in1.]
Any member of a group of astringent vegetable substances, the tannins, which possess the property of combining with animal hide and converting it into leather.
The first member of this group isolated and so named was the tannin of gall-nuts, subsequently also called tannic acid; and to this the names tannin and tannic acid are still often specifically applied. But the discovery that the astringent principles of other vegetable substances were not chemically identical with that of gall-nuts made it needful to distinguish the various tannins. The original or ‘ordinary tannin’ became distinctively gallotannin, other members of the group being named caffetannin, catechutannin, kinotannin, quercitannin, etc. (cf. tannic), or particularized as oak-bark tannin, alder, beech, hop, horse-chestnut, larch, rhatany tannin, according to their source.
1802Nicholson's Jrnl. II. 198 Abridgment of a Memoir of Mr. Proust on Tanin and its Species. 1804Phil. Trans. XCIV. 210 The effects which it produced on gelatin, also demonstrate the presence of tannin. 1836Brande Chem. (ed. 4) 928 note, The tannin of catechu is said to contain less oxygen than that of galls. 1838T. Thomson Chem. Org. Bodies 109 Pure tannin is colourless. 1867Baker Nile Tribut. viii. (1872) 123 It is rich in a hard gum, which appears to be almost pure tannin. 1895Muir & Morley Watts' Dict. Chem. V. 632/1 The origin of tannin in plants has given rise to much debate.
b. attrib. and Comb., as tannin drop, tannin pill, tannin treatment; tannin-like adj.; tannin-glycerol, glycerin of tannic acid; tannin-sac, a vessel in plants which secretes tannin.
1874Garrod & Baxter Mat. Med. (1880) 357 Tannin Lozenges. 1875Bennett & Dyer Sachs' Bot. 628 Tannin-like compounds are formed in particular cells. 1879St. George's Hosp. Rep. IX. 800 It soon passed off again with rest and the opium and digitalis and tannin pills. 1884Bower & Scott De Bary's Phaner. 153 We may here introduce these organs as Tannin-sacs. They occur as elongated sacs, especially near to the vascular bundles, in the parenchyma of the stem and petiole of many Ferns (Marsilia, Polypodiaceæ, Cyatheaceæ, Marattiaceæ, &c.). 1898P. Manson Trop. Diseases vi. 121 The tannin treatment..might also be tried.
Hence ˈtannined |-ɪnd| a., charged or impregnated with tannin; tanninˈgenic a., in tanningenic acid, a synonym of catechuic acid and catechin.
1898E. F. Spence in Westm. Gaz. 6 Sept. 3/3 For breakfast we had undrinkable coffee, which we exchanged for tannined tea. 1852C. Morfit Tanning & Currying (1853) 69 Catechuine or tanningenic acid. |