98 PRUNUS LAUROCERASUS 



The presence of these substances in cherry-laurel leaves is inferred 

 from the fact that when they are cut and crushed and submitted 

 to distillation with water, they yield a volatile oil which, like that 

 produced under the same conditions from bitter almonds, contains 

 hydrocyanic acid, and has always been regarded as identical with 

 the essential oil of bitter almonds. According to Tilden, the 

 crude essential oil of cherry-laurel leaves "consists mainly of 

 benzoic aldehyd, accompanied with hydrocyanic acid (less than 

 2 per cent., according to Umney), volatile oil, possibly benzoic 

 alcohol (perhaps 1 per cent.), and minute quantities of an odorous 

 resin." The experiments of Schaer, made at the request of Dr. 

 Fliickiger, show that the fresh vigorous unwounded cherry-laurel 

 leaves do not {( evolve naturally a trace of hydrocyanic acid, 

 though they yield it on the slightest puncture." According 

 to Christison, the buds and unexpanded young leaves of the 

 cherry -laurel yield ten times as much essential oil as the leaves of 

 twelve months old. The experiments of Broeker also show, that 

 the amount of hydrocyanic acid yielded by the leaves varies with 

 the season, the age of the plant, the character of the soil, and of 

 the weather. He found the proportion of the acid to be obtained 

 from the leaves was greatest in July and August, and least in 

 February. 



Besides the above supposed constituents of the leaves, they 

 contain sugar, fat, and a small quantity of tannic acid, hence 

 their watery infusion becomes green by the addition of perchloride 

 of iron. 



Medical Properties and Uses. Cherry-Laurel leaves have similar 

 properties to hydrocyanic acid, and have sometimes been used 

 both internally as a sedative; and externally in the form of a 

 poultice mixed with linseed meal, as an application to painful 

 ulcers, &c. But the official laurel water, which is more commonly 

 and properly termed cherry-laurel water, is the usual form of 

 administration, and is much employed in various parts of Europe. 

 It is applicable in all cases for which hydrocyanic acid is used, 

 and is sometimes regarded as an elegant mode of administering 

 that acid. In this country and the United States its use has 



