INULIN. | 127 
very distinctly on the sphero-crystals, and the amorphous 
masses are neither doubly refractive nor stratified. 
With this deficiency of organic structure is connected also 
a lesser capacity of combining with water. In opposition to 
amylum, the composition of which corresponds to the formula 
(C,H,,0,),+3H,0 (= 14.2 percent of water), air-dry inulin con- 
tains only from 5 to 10 per cent of water. On the other hand, it 
dissolves readily in hot water and separates therefrom unchanged 
upon cooling, provided the solution had not been exposed for a 
long time to a higher temperature. In the latter case, the inu- 
lin very readily passes into uncrystallizable, levogyrate sugar. 
Fig. 55.—Groups of fine needle-shaped crystals (rhaphides) from Radix Sarsaparille. 
The solution of inulin itself likewise deviates the plane of 
polarization of a ray of light to the left; solutions of starch, 
which are obtained by the aid of chloral hydrate or by certain 
salts (page 110), rotate tothe right, as does also the crystallizable 
grape sugar obtained from starch. The aqueous solution of 
inulin is never paste-like ; it is an actual solution in the ordi- 
nary sense, while the paste of starch is produced only through a 
swelling of the granules. 
Tnulin is not colored by iodine. Indeed, we possess no heat 
for it, and are only capable of recognizing it by confirming sey- 
eral of its physical properties. 
The amount of inulin contained in the Composite is very 
