516 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



or compound from 0.003 to 0.025 mm. in diameter, varying from 

 spheroidal to somewhat flattened reniform, among which are plano- 

 convex or polyhedral forms. 



Constituents. The drug apparently contains a bitter glucoside, 

 chionanthin; possibly also a saponin; ash from 4 to 5 per cent. 



Literature. Schulz, Pharm. Zeitschr. f. Russl., 1893. 



FRAXINUS. White Ash Bark. The bark of Fraxinus americana 

 (Fam. Oleacese), a large forest tree of the northern United States 

 and Canada. Both the stem and root barks are collected, the latter 

 being preferred. The bark is collected in the spring, from the 

 branches and trunks of trees from 10 to 25 years of age. The outer 

 periderm should be removed. Sometimes the root bark is collected 

 at the same time. 



Description. In nearly flattened pieces from 10 to 15 cm. in 

 length, 2.5 to 7.5 cm. in breadth and 3 to 10 mm. in thickness; 

 outer surface reddish-brown, irregularly furrowed and with numerous 

 shallow patches, frequently with the yellowish-gray outer periderm 

 present ; inner surface yellowish-brown, nearly smooth, somewhat 

 longitudinally striate; fracture uneven, short-fibrous; odor slight 

 aromatic; taste bitter, slightly aromatic and acrid. 



Inner Structure. Periderm consisting of thick-walled concavo- 

 convex and somewhat collapsed cells having a reddish-brown amor- 

 phous content; outer layers of cortex of several layers of very small 

 parenchyma cells containing a light reddish-brown amorphous sub- 

 stance; inner and middle bark of concentric bands of sclerenchyma, 

 consisting of radially elongated groups of bast fibers, large groups 

 of stone cells in which are included frequently small groups of bast 

 fibers separated by equally broad concentric bands of leptome and 

 parenchyma; medullary rays 1 to 7 rows wide and 5 to 20 rows deep, 

 containing either a colorless, or yellowish-brown, granular or amor- 

 phous content; stone cells very irregular, varying from 0.050 to 0.160 

 mm. in length, having thick, finely lamellated, and slightly porous 

 walls; bast fibers, attaining a length of 1.2 mm., having thick porous 

 walls, wavy margins and sharp pointed, more or less beaked and 

 short branching ends. 



Constituents. A volatile oil; an alkaloid; several resins; starch 

 and sugar; neither tannic nor gallic acids are apparently present. 



Allied Drug. The bark of the young twigs of Fraxinus excelsior, 

 a tree growing in Europe and northern Asia, is used in European 

 countries. It is collected in spring, consists of quills having a thick- 

 ness of 2 to 3 mm. The bark is externally grayish- or grayish-green, 

 somewhat scaly; the inner surface light yellowish; the fracture is 



