This body, which has been found occasionally in volatile oils (for instance, in cognac oil), can be isolated by distillation on a water bath and identified by the Isonitrile reaction. This consists in that a small amount of the suspected distillate is treated with a few drops of aniline and alcoholic caustic soda solution, and gently heated. In the presence of chloroform the noxious and exceedingly disagreeable smelling vapors of phenyl-Isonitrile are formed.