194 HISTOLOGY OF MEDICINAL PLANTS 
INULIN 
Inulin is the reserve carbohydrate material found | in the 
plants of the composite family. 
The medicinal plants containing inulin are dandelion, ning 
elecampane, pyrethrum, and burdock. Plate 77, Figs. 1 and 2 
show masses of inulin in dandelion and pyrethrum. 
In these plants the inulin occurs in the form of irregular, 
structureless, grayish-white masses (Plate 77). In powdered 
drugs inulin occurs either in the parenchyma cell or as irregular 
isolated fragments of variable size and form. Inulin is structure- 
less and the inulin from one plant cannot be distinguished 
microscopically from the inulin of another plant. For this 
reason inulin has little or no diagnostic value. The presence 
or absence of inulin should always be noted, however, in examin- 
ing powdered drugs, because only a few drugs contain inulin. 
When cold water is added to a powder containing inulin it 
dissolves. Solution will take place more quickly, however, in 
hot water. Inulin occurs in the living plant in the form of cell 
sap. If fresh sections of the plant are placed in alcohol or 
glycerine, the inulin precipitates in the form of crystals. 
MUCILAGE 
Mucilage is of common occurrence in medicinal plants. 
Characteristic mucilage cavities filled with mucilage occur in 
sassafras stem (Plate 66, Fig. 2), in elm bark (Plate 66, Fig. 1), 
in althea root, in the outer layer of mustard seed, and in the 
stem of cactus grandiflorus. In addition, mucilage is found 
associated with raphides in the crystal cells of sarsaparilla, 
squill, false unicorn, and polygonatum. 
When drugs containing mucilage are added to alcohol, 
glycerine, and water mixture, the mucilage swells slightly and 
becomes distinctly striated, but it will not dissolve for a long 
time. Refer to Plate 79, Fig. 6. 
Mucilage, when associated with raphides, swells and rapidly 
dissolves when added to alcohol, glycerine, and water mixture. 
The mucilage is, therefore, different from the mucilage found 
in mucilage cavities, because it is more readily soluble. 
In coarse-powdered bark and other mucilage containing 
