734 



BOTANY AND PHARMACOGNOSY. 



Rhapontic rhubarb contains a crystalline glucoside rhapon- 

 ticin, which is colored purplish-red with sulphuric acid, changing 

 to orange. It is insohible in ether and readily separates from a 

 dilute alcoholic fluid extract on the addition of ether. 



Fig. 290. Curcuma (Turmeric): P, fragments of parenchyma containing swollen 

 and altered starch grains which form an indistinguishable mass within the cells and consti- 

 tute the greater proportion of the powder; T, tracheae; S, unaltered starch grains. 



P In Monoclinic Prisms. 



50. CALUMBA.— (See No. 60.) 



51. CURCUMA. — Bright yellow (Fig. 290) ; crystals few, 

 2 to 4 /x in diameter; altered starch grains (test with iodine) in 

 irregular masses from 100 to 140 /* in diameter, having the shape 

 of the cell in which they occur ; bright yellow oil-secretion cells ; 

 the pigment is soluble in solutions of chloral or chloral-glycerin, 

 essential oils and alcohol. The latter solution becomes cherry-red 

 with boric acid, changing to bluish-black with ammonia. Curry 

 POWDER consists of allspice, caraway, cardamom, clove, coriander, 

 fenugreek, ginger, pepper and turmeric. 



