86 VEGETABLE DRUGS WITH ORGANIC STRUCTURE. 



from 5 to 8 cm. in length, and 2^^ to 4 cm. in width. 

 The thickness of the rind is from 2 to 8 mm. 



The color is grayish-brown, sometimes having a soft 

 brown bloom, which on being rubbed off reveals the more 

 or less translucent brown shell of the gall beneath. 



The fracture is horny or splintery and the internal 

 surface is smooth and generally lighter in color than the 

 outside. In the interior, products of insect life may be 

 found. The Japanese galls are usually smaller. 



Microscopical Characteristics .—^Kn inner and an outer 

 epidermis-like arrangement of cubical parenchyma cells 

 is to be noted ; those on the outer wall having outgrowths 

 of short one- to two-celled simple hairs. The centre of 

 the rind is made up of parenchymatic cells which, from 

 without inward, are at first tangentially arranged, and 

 later grow larger, irregular, and mesh-like in disposition, 

 while here and there are to be observed simple vessel 

 bundles, made up of a few small spiral vessels and one or 

 two small sieve tubes and sometimes milk (?) tubes. 



The cells of the inner region are cubical, somewhat like 

 those of the outer wall, but may be arranged in but one 

 or two layers. The parenchymatic cells contain irregular 

 masses of tannic acid and a number of green circular 

 bodies and small starch grains. 



Chemistry. — Tannic acid in large quantities; gallic 

 acid, fat, resin, ash, 2 per cent. 



Other Galls. — A large number of other types of galls 

 are used commercially, some of the most important 

 being : 



(a) Hungarian Galls, derived from Quercus sessili- 

 flora, and pedunculated, by means of insect, Cynips 

 leguicola. Some are small; up to 1.5 cm. in size, red- 

 dish brown in color. Again, there are large ones, 

 on Quercus pedunculata by means of Cynips Hungarica. 

 These are grayish or brownish, circular, 3.5 to 5 cm. in 

 diameter, with irregular warty surfaces. 



