STONE FRUITS.
Plums and cherries, peaches and apricots are stone fruits. The pulpy flesh encloses the single seed, which has a hard shell, like a nut. The trees have a resinous sap that flows out to heal wounds in the bark. The drug, hydrocyanic acid, gives the characteristic bitter taste to the sap and the pits of the fruit. It is poisonous, but does not
affect the flesh. Stone fruits have been improved by cultivation until they represent one of the im portant fruit groups of the Temperate Zones.