A commoner quality, called “block-gambier,” instead of being cut into cubes, is run into large oblong blocks of about 250 lb. weight, which are wrapped in matting and exported in a pasty condition. These contain 35-40 per cent. of tannin, as estimated by the hide-powder method, while the best cubes reach 50-65 per cent. Besides the forms named, various others are made, principally for native use in chewing with betel-nut in the form of small biscuits, or in thin discs (“wafer gambier”) by running the pasty mass into bamboos and cutting the cylinder so formed into thin slices. These forms are usually light in colour, and very rich in catechin. For details of the chemistry and employment of gambier, see pp. 228, 231, 239, etc. APOCYNACEÆ. _Aspidospermum quebracho_. Sp. _Quebracho blanco_. Brazil. Bark contains aspidospermin, an alkaloid used in medicine, but both bark and wood are poor in tannin. _Quebracho colorado_, see ANACARDIACEÆ, p. 269. ERICACEÆ, Heath Family. _Arctostaphylos_ (or _Arbutus_) _uva-ursi_, Bearberry. Used in Russia, Finland; twigs and leaves said to contain 14 per cent. tannin. Often adulterated with leaves of _Vaccinium vitis-idæ_ or Cowberry. _Arbutus unedo_, Common Arbutus. Leaves, fruit and bark used on Mediterranean coasts. VACCINIÆ. _Vaccinium Myrtillus_, Bilberry. Used in Piedmont. SAXIFRAGEÆ. _Weimannia glabra_ L., “Curtidor” bark. Venezuela. _Weimannia macrostachys_ D.C. Reunion. _Weimannia racemosa_, New Zealand Towai or Tawheri bark. These species contain 10-13 per cent. of iron-blueing tannin, and have been practically used, but are not of much importance. TAMARISCINIÆ. Most of the members of this group are poor in tannin, but several species have galls which are rich. _Tamarix africana_; Egypt, Algeria. Galls containing 26-56 per cent. tannin. The small twigs are collected in Tunis, and when dried and ground are imported into Sicily to be used for the adulteration of sumach under the name of “Brusca,” and contain about 9 per cent. of tannin. (Cp. p. 272.) _T. articulata_, Morocco, yields galls produced by aphides, called in Arabia _Takout_, and stated by Vogel to contain 43 per cent. of tannin. _Tamarix gallica_, used in Spain and Italy. OXALIDEÆ. _Oxalis gigantea_, source of _churco_ bark, Chili. A thin, brittle, dark red bark, mostly about 2 mm. thick, cork and ross entirely absent. The bark is brittle, and the cells thin. It contains about 25 per cent. of an easily extracted, dark red tannin, giving green-blacks with iron. The bark has been incorrectly attributed to _Fuchsia macrostemma_. (Cp. Von Höhnel, ‘Die Gerberinden,’ p. 125, and this book, p. 284.) COMBRETACEÆ. Several families of this genus contain trees rich in tannin, but most important are the Myrobalans (often, but incorrectly, written Myrabolams or Myrabolans), the unripe fruit of various species of Indian _Terminalia_. [Illustration: FIG. 57.--Myrobalan Tree (_Terminalia Chebula_).]