198 HISTOLOGY OF MEDICINAL PLANTS 
DESCRIPTION OF ALEURONE GRAINS 
The aleurone grains of curcas (Plate 77a, Fig. 1) 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 77a, 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 77a, 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 77a, 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 croton-oil seed (Plate 77a, Fig. 5) 
are circular in outline, variable in form, and each grain contains 
from one to seven globoids. 
In sesame seed (Plate 77a, 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 77a, 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. 
