C60H60O22 (?)  , which hydrolyses to rhamnose and hesperetin, C16H14O6, the phloroglucin ester of meta-oxy-para-methoxycinnamic acid or isoferulic acid, C,oHioO4 . We may here include various coumarin and benzo-y-pyrone derivatives . Aesculin, C16H16O9, occurring in horse-chestnut, and daphnin, occurring in Daphne alpine, are isomeric; the former hydrolyses to glucose and aesculetin (4.5-dioxycoumarin), the latter to glucose and daphnetin (3.4-dioxycoumarin) . Fraxin, C,EH,80,o, occurring in Fraxinus excelsior, and with aesculin in horse-chestnut, hydrolyses to glucose and fraxetin, the mono-methyl ester of a trioxycoumarin . Flavone or benzo-7-pyrone derivatives are very numerous; in many cases they (or the non-sugar part of the molecule) are vegetable dyestuffs . Quercitrin, C21H22O12, is a yellow dyestuff found in Quercus tinctoria; it hydrolyses to rhamnose and quercetin, a dioxy-/3-phenyl-trioxybenzoy-pyrone . Rhamnetin, a splitting product of the glucosides of Rhamnus, is monomethyl quercetin; fisetin, from Rhus cotinus, is monoxyquercetin; chrysin is phenyl-dioxybenzo-y-pyrone . Saponarin, a glucoside found.in Saponaria officinalis, is a related compound . Strophanthin is the name given to three different compounds, two obtained from Strophanthus Kombe and one from S. hispidus . 4 . Anthracene Derivatives.—These are generally substituted anthraquinones; many have medicinal applications, being used as purgatives, while one, ruberythric acid, yields the valuable dye-stuff madder, the base of which is alizarin (q.v.) . Chrysophanic acid, a dioxymethylanthraquinone, occurs in rhubarb, which also contains emodin, a trioxymethylanthraquinone; this substance occurs in combination with rhamnose in frangula bark .

The most important cyanogenetic glucoside is

amygdalin, which occurs in bitter almonds . The enzyme maltase decomposes it into glucose and mandelic nitrile glucoside; the latter is broken down by emulsin into glucose, benzaldehyde and prussic acid . Emulsin also decomposes amygdalin directly into these compounds without the intermediate formation of mandelic nitrile glucoside . Several other glucosides of this nature have been isolated . The saponins are a group of substances characterized by forming a lather with water; they occur in soap-bark (q.v.) . Mention may also be made of indican, the glucoside of the indigo plant; this is hydrolysed by the indigo ferment, indimulsin, to indoxyl and indiglucin .