THE GALL OR DYERS’ OAK. 735

Induced, it eats its way out. If we examine those galls from which thej. Ilr >al has escaped, we observe externally a circular hole, of about av ' e in diameter, leading to a canal of from 2 j to 3| lines long, whichIj Sse s to the centre of the gall. But in those galls in which the insectin? not P u t off' its pupa state, we find neither an external hole nor aner nal canal. Those galls from which the insect has escaped are com-to ,?dy larger, lighter coloured, and less astringent: they are termede galls.

Oj Merge.—N utgalls are imported principally from Turkey: hence

£ 6lr name of Turkey Galls {Gallo: turcica). They usually come from^stantinople, but sometimes from Smyrna. Those brought froml e Pp° are the produce of Mosul {Aleppo or Mosul Galls), and are the4 j *■ Smyrna Galls are not so heavy, are lighter coloured, and contain4/- ^ er ^mixture of white galls than those brought from Aleppo . Easttjjj 10 Galls are brought from Bombay. Ainslie {Mat. Indica, vol. i. p. 145)in i) S ’ U that the greater part of the galls found in Indian bazars growj^nsia, and are brought to the peninsula by Arab merchants.”v in f CRI1 " rl0N -—lu commerce, three kinds of galls are distinguished,i • Gack or blue, green, and white. But there is no essential distinctionl"een the two first.

(q ' Black or Blue Nutgalls {Gallee nigra seu car ulcer); Green Nutgallsc nl] ^ ^ides). —These are gathered before the insect has escaped, and are4 ^ e d by the natives Yerli. They vary from the size of a pea to that ofiji^i-nut, and have a grayish colour. The smallest have a blackish-Hj . hut, and are distinguished by the name of black or blue galls, while^ j, ai 'ger and greener varieties are called green galls. Externally theyt erv Ire 5 Ue ntly tuberculated, but the surface of the tubercles and of the in-eil ing spaces is usually smooth. Their texture is compact, but fragile,have no odour, but a styptic and powerfully astringent taste.

% Galls {Gallee alba). —These are for the most part gathered

c tJ ] r die insect has escaped, and hence they are perforated with a cir-l^hole. They are larger, lighter coloured (being yellowish or whitish),'^lu?° m Pact, less heavy, and less astringent. They are of inferior

iC^moN.-^Nutgalls were analyzed by Sir H. Davy {Phil. Trans.who obtained the following results:—

x r Tannin . 26*0

blatters c . ) Gallic acid, with a little extractive_ :. G‘2

soluble in water=37 ; viz. \ Mucilage and matters rendered insoluble by evaporation 2*4

Matte • (. Carbonate of lime and saline matter. 2'4

* ^soluble in water (lignin) . 630

00(1 Aleppo Nutgalls.100-0

l. .

acid (Acidum Tannicum ).—The substance formerly described in chemicalHi ch A’, the name of tannin, is tannic acid mixed with some foreign matters, from( lS Vei T difficult to free it.

. extracted from nutgalls by ether, in the percolation or displacement apparatusi^pre ° ^placement) as recommended by Pelouze {Ann. de Chim. et dePhys. liv.),thispa r ! en ^ s hself as a non-crystalline, white solid, sometimes having a yellowish tinge.- s °f nutgalls yield from 35 to 40 parts of tannic acid,j hi),, 0l i° vv iug are the essential characteristics of this substance :—It has an intensely" e ^iwi\ C . nt t ? ste > an d produces, with a solution of gelatin, a white precipitate (tannate of‘ ’ VVl tli a solution of a sesquisalt of iron, a deep blue compound (tannate of iron );