. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. INULIN. 61 form wliich are distinctly radiating in structure. Occasionally tliese masses have large rifts which run across the surface of the sphere. In composition, inulin closely resembles starch, but does not give any color with iodine. To de- tect it when in solution, a thin sec- tion of the plant containing it is moistened on the glass slide with absolute alcohol, when a cloudj- pre- cipitate will at once appear; in a short time (the supply of alcohol havi
. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. INULIN. 61 form wliich are distinctly radiating in structure. Occasionally tliese masses have large rifts which run across the surface of the sphere. In composition, inulin closely resembles starch, but does not give any color with iodine. To de- tect it when in solution, a thin sec- tion of the plant containing it is moistened on the glass slide with absolute alcohol, when a cloudj- pre- cipitate will at once appear; in a short time (the supply of alcohol having been replenished as it evap- orates) the specimen grows clearer, and small sphserocrj'stals of inulin are seen. If now the specimen is carefully washed with water, the smaller granules disappear and the well-defined remain. 184. The carbohydrates dissolred in the cell-sap maj- be grouped in two classes : (1) those whicli are isomers of cellulose (i. e., have the same per- centage composition, ^), and (2) the sugars. 1. The isomers of cellulose are mucilage, gums, and dextrin, all of which are probably derivatives of starch. Various sub- stances intermediate between them have been described, but the above are all that need now be taken into account. («) Mucilage, when not plainly resulting from the breaking up of the cell- wall, is colored red by rosolic acid, and the color is not readil}' removed by alcohol, {b) The gums, of which cherry gum may be taken as an example, are not tinged by rosolic acid, (c) Dextrin can be detected by Trommer's test, which Sachs ap- plies as follows: a section which is at least a few cells in thick- ness is placed in a porcelain capsule with a strong solution of cupric sulphate, and the liquid is heated to boiling; the specimen is then washed in water, and dipped at once in hot potassa. If the cells contain either dextrin or grape-sugar, there will immediately appear a reddish precipitate. To discriminate be- tween dextrin and grape-sug
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