ACACIA.

1147

^ A. Senegal, Wilklenow ; A. Verek, Adanson.—Arabia and Africa ,s °} n Senegal to the Cape of Good Hope . Abundant in the forest ofsV e .near Senegal. Yields gum Senegal in vermiform, ovoidal, orl neroidal tears, which are wrinkled externally, but are transparentEternally.

U Pro »uction of Gum.— The gum of the Acacia trees flows, in thes t a te, from the trunk and branches, and hardens by exposure to•a*. It usually exudes spontaneously (See some remarks on the causec ,*e exudation of gum, p. 1139). In some instances, however, the dis-j ar ge is facilitated by incisions. In Barbary the largest quantity of gum(i ,P r °cured during the hot and parching months of July and August.

t more sickly the tree appears, the more gum it yields; and thein°i\ er *^ le weat her, the more prolific it is. A wet winter and a cool or. d summer are unfavourable to the production of gum” (Jackson,ccount of the Empire of Marocco, p. 137, 3rd ed.) In Senegal the^ e ’ r ta }e gins to flow when the tree first opens its flowers (Adanson , Mem.

^ Ac. d. Sc. cl. Paris , 1773, p. 8); and it continues during the rainya s° n till the month of December, when it is collected for the first time,other collection of the gum is made in the month of March, from inci-s - R ' s 111 the bark, which the extreme dryness of the air at that time ist . to render necessary (Demanet, Nouv. Hist, de VAfrique Francoise,pP- 56, quoted by Woodville, Med. Bot. vol. ii. p. 188).a . °Mmekce. —Acacia gum is the produce of Africa principally, and oft ’ a ' It is imported from the Levant and other parts of the Medi-Co ariea n, from Barbary, Senegal, the East Indies, the Cape , &c. Itp e ^ es over in chests, casks, skins, serons, bags, &c. The duty on it is 6s.m.tavt. The following are the quantities on which duty was paid in[Trade List)

Gum from the East Indies .. 7,869 cwts.

Senegal Gum . 24,698

Other sorts of Gum . 7,759

Total . 40,326 cwts.

k^EscRiPTioN.—Acacia gum ( gummi acacia ) occurs in variable-sizedt as j S} w hich are inodorous, more or less coloured, have a slightly sweetish'ha.t\? n( l a 8 rea, ta r or less degree of transparency. Ehrenberg assertssid l le oharacters of gum of the same species of plant are liable to con-0pa era ble variation. Thus the same tree may yield a transparent or anhrin* Ue ’ a hght or a dark-coloured, gum. The following are the mostjtant varieties of Acacia gum:—

' Turkey or Arabic Gum (Gummi turcicum seu arabicum; Gummiijjj 0%e verum, Martius; Gomme arabique vraie, Guibourt). This ishey rte< ^ from Leghorn, Malta, Trieste, Gibraltar , Smyrna, Alexandria,b a (q ° ut > Constantinople , &c. It is the produce of Acacia vera, and pro-°r a ^,° f other species, especially A. arabica. It occurs in rounded tears,'tain ° r P 10us or angular pieces, varying in size from a pea to that of aothe Ut ’ ° r even larger than this; some of the pieces being transparent,th ern S ta°re or less opaque, from innumerable cracks extending throughn° Qf j I* 1 has a glassy lustre, is white, yellow, or wine-yellow, and hasto Imo' 1 /’ or h any, an acid one. Its specific gravity varies from 1 - 316— It may be readily broken into small fragments. It is entirely