Note 2372 — I.—PHÆNOGAMOUS OR FLOWERING PLANTS. (continued 19)

The following is a striking experiment, showing some of these changes of colour:—Place a little crushed turmeric or the powder on blotting paper, and moisten it repeatedly with chloroform, allowing the latter to evaporate. There will thus be formed on the paper a yellow stain, which on addition of a slightly acidulated solution of borax and drying assumes a purple hue. If the paper is now sprinkled with dilute ammonia it will acquire a transient blue. This reaction enables one to recognize the presence of turmeric in powdered rhubarb or mustard.