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. 



Fig. 232. Species of Rubus; A, wild red raspberry (Rubus strigosus); B, running 

 swamp blackberry (Rubus hispidus); C, D, high bush blackberry (Rubus nigrobaccus) , 

 the former fruiting and the latter flowering. 



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 principled found in arbor vitse {Thuja ocddentalis) . 



RUBUS.— BLACKBERRY BARK.— The bark of the rhi- 

 zome of the perennial shrubs (p. 288) Rubus villosus, R. nigrOT 



