- VOLATILE OILS AND FRACTIONS OF VOLATILE OILS

Volatile or essential oils may be defined as oily liquids which are entirely, or almost entirely, volatile without decomposition. A few, e.g. oil of anise, are solid at 15.5° c., but melt to form a liquid at slightly higher temperatures. Those volatile oils prepared other than by distillation, e.g. oil of lemon, contain a small proportion of non-volatile matter.