530 



BOTANY AND PHARMACOGNOSY. 



Inner Structure. See Figs. 231 ; 231a ; 300, H. 



Constituents. About 8 per cent, of a peculiar, colorless 

 acid resin, which is soluble in water and becomes reddish and 

 insoluble on exposure to air. The drug also contains fixed oil ; 

 tannin ; starch and calcium oxalate. 



e 



h 



pa 



Fig. 232. Euonymus airopropureus: A, flowering branch showing distinctly petiolate 

 leaf; B, cluster of the smooth capsular fruits; E. americantis: C, fruiting branch showing 

 the opposite almost sessile leaves and axillary verrucose capsule; D, cross-section of stem 

 showing a stoma sunk beneath the epidermis; E, cross-section of stem showing epidermis 

 (e), hypodermis (h), palisade cells of cortex (p), parenchyma cells (pa), pericycle (s) and 

 portion of the leptome (1). After Holm. 



The FLOWERS of the cotton plant contain an interesting gluco- 

 side, gossypetin, which becomes green on oxidation and is colored 

 orange-red with solutions of the alkalies. It somewhat resembles 

 a similar principle found in arbor vit?e {Thuja occidentalis) . 



RUBUS. BLACKBERRY BARK. The bark of the rhi- 

 zome of the perennial shrubs (p. 288) Rubits villosus, R. nigro- 



