198 HISTOLOGY OF MEDICINAL PLANTS 



DESCRIPTION OF ALEURONE GRAINS 



The aleurone grains of curcas (Plate 770, Fig. i) vary in form 

 from circular to lens-shaped, and each grain contains one or 

 more globoids. The globoids are larger when they occur singly. 

 In sunflower seed (Plate 770, Fig. 2) the grains vary from reni- 

 form to oval, and one or more globoids are present; many occur 

 in the center of the grain. 



The aleurone grains of flaxseed (Plate 770, Fig. 3) resemble 

 in form those of sunflower seed, but the grains are uniformly 

 larger and some of the grains contain as many as five 

 globoids. 



In bitter almond (Plate 770, Fig. 4) the aleurone grains are 

 mostly circular, but a few are nearly lens-shaped. A few of 

 the large, rounded grains contain as many as nine globoids; 

 in such cases one of the globoids is likely to be larger than the 

 others. The aleurone grains of cro ton-oil seed (Plate 770, Fig. 5) 

 are circular in outline, variable in form, and each grain contains 

 from one to seven globoids. 



In sesame seed (Plate 770, Fig. 6) the typical grain is angled 

 in outline and the large globoid occurs in the narrow or con- 

 stricted end. 



The aleurone grains of castor-oil seed (Plate 770, Fig. 7) re- 

 semble those of sesame seed, but they are much larger, and 

 many of the grains contain three large globoids. When these 

 grains are mounted in sodium-phosphate solution, the crystal- 

 loid becomes visible. 



TESTS FOR ALEURONE GRAINS 



Aleurone grains are colored yellow with nitric acid and red 

 with Millon's reagent. 



The proteid substance of the mass of the grain, of the globoid, 

 and of the crystalloid, reacts differently with different reagents 

 and dyes. 



The ground substance and the crystalloids are soluble in 

 dilute alkali, while the globoids are insoluble in dilute alkali. 



The ground substance and crystalloids are soluble in sodium 

 phosphate, while the globoids are insoluble in sodium phosphate. 



Calcium oxalate is insoluble in alkali and acetic acid, but 

 it dissolves in hydrochloric acid. 



