68 HOW CROPS GROW. 
washed with water to which some alcohol has been added.—Zennebderg’s 
Journal fiir Landwirthschaft, 1862, p. 206. 
Inulin, C,, I,, O,,, closely resembles starch in many 
points, and appears to replace that body in the roots of 
the artichoke, elecampane, dahlia, dandelion, chicory, and 
other plants of the same natural family (composite). It 
may be obtained in the form of minnte white grains, 
which dissolve easily in hot water, and mostly separate 
again as the water cools. Unlike starch, inulin exists in a 
liquid form in the roots above named, and separates in 
grains from the clear pressed juice when this is kept some 
time. According to Bouchardat, the juice of the dahlia 
tuber, expressed in winter, becomes a semi-solid white mass 
in this way, after reposing some hours, from the separa- 
tion of 8 per cent of this substance. 
Inulin, when pure, gives no coloration with iodine. It 
may be recognized in plants, where it occurs in a solution 
usually of the consistence of a thin oil, by soaking a slice 
of the plant in strong alcohol. Inulin is insoluble in this 
liquid, and under its influence shortly separates as a solid 
in the form of spherical granules, which may be identified 
with the aid of the microscope. 
When long boiled with water it is slowly but complete- 
ly converted into a kind of sugar, (levulose); hot dilute 
acids accomplish the same transformation in a short time. 
It is digested by animals, and doubtless has the same value 
for food as starch. 
In chemical composition, inulin agrees perfectly with 
cellulose and starch; see p. 60. 
Dextrin, C,, H,, O,,, has been thought to occur in small 
quantity dissolved in the sap of all plants. According to 
Von Bibra’s late investigations, the substance existing in 
bread-grains which earlier experimenters believed to be 
dextrin, is in reality gum. Busse, who has still more 
recently examined various young cereal plants and seeds, 
