NUTGALL 167 



uneven, coarsely fibrous, surface porous and dotted with groups of 

 white sclerenchymatous cells and fibers; odor slight; taste astringent. 



Inner Structure. For illustration of microscopic sections, consult 

 Kraemer's Applied and Economic Botany, p. 511. 



Powder. Light brown; bast fibers long, thick-walled, lignified; 

 crystal fibers containing rosette aggregates or monoclinic prisms of 

 calcium oxalate from 0.010 to 0.025 mm. in diameter: stone cells 

 thick-walled, with numerous lamellae and simple pores: parenchyma 

 with irregular yellowish-brown tannin masses. 



Constituents. Tannin about 10 per cent; starch and calcium 

 oxalate. The tannin yields upon sublimation a crystalline principle 

 resembling pyrocatechin; upon fusion with potassium hydrate, a 

 phenol similar to protocatechuic acid is formed; dilute solutions are 

 colored olive-brown with ferric chloride and possess a slight fluores- 

 cence; alkalies give a deep red color to the solutions. 



Allied Plants. Quercus robur, indigenous to Europe, is the source 

 of the bark used in England and Continental Europe ; the bark closely 

 resembles that of Quercus alba, but the periderm is not removed; it 

 contains from 10 to 16 per cent of tannin, besides gallic and ellagic 

 acids. Quercus velutina, or black oak, yields the quercitron bark, 

 which resembles that of Quercus alba, but is reddish-brown, and 

 tinges the saliva yellowish; it contains besides tannin a yellow glu- 

 cosidal principle quercitrin, which yields quercetin, a yellow coloring 

 principle. 



Literature. Kraemer, Amer. Jour. Pharm., 1890, p. 236. 



GALLA. Nutgall. An abnormal development on the young 

 twigs of Quercus infectoria (Fam. Cupuliferae) due to the puncture 

 and presence of the deposited ova of a Hymenopter.ous insect, Cynips 

 tinctoria. The galls are collected before the maturing of the insect, 

 and are obtained principally from Aleppo, in Asiatic Turkey. 



There are three stages in the development of galls corresponding 

 to the development of the insect and during which the composition 

 varies: (1) When the galls are first formed and the larva is beginning 

 to develop, the cells of the outer zone, as well as those of the central 

 zone, contain numerous small starch grains. (2) When the insect 

 reaches the chrysalis stage, the starch in the cells near the middle 

 of the galls is replaced in part by gallic acid, while the cells at the 

 center and near the periphery contain masses of tannic'acid. (3) 

 When the winged insect is developed nearly all of the cells contain 

 amorphous masses of tannic acid with some adhering crystals of gallic 

 acid. After the insect has emerged from the gall the constituents 

 again undergo a change, depending largely on the presence of moisture, 



