467 
CHERRY-LAUREL WATER. 
BY C. UMNEY, F.C.S. 
The introduction into the British pharmacopoeias of 1864 and 1867 of aq. 
laurocerasi has had a marked effect upon the consumption of this preparation, 
the demand being now at least two or three times greater than it was five or 
six years since. 
It has been long known that in strength, and therefore in dose, this water is 
liable to considerable variation ; but, as far as I am aware, no examination of 
the various waters as found in pharmacy, purporting to be of the “ officinal 
strength,” has been published, neither has any suggestion been made to remedy 
the evil of the varied proportion of its poisonous principle. With a view, 
therefore, to obtain uniformity in strength and action of this medicine, these 
experiments were made. The ‘ British Pharmacopoeia 1 directs us to take— 
Fresh cherry-laurel leaves.1 pound. 
Water.2^- pints. 
Crush the leaves, macerate them in water for twenty-four hours, then distil one 
pint. 
The compilers of the Pharmacopoeia have here adopted the directions of the 
; Dublin Pharmacopoeia ’ in the maceration of the leaves for twenty-four hours 
previous to distillation, and have rejected the Edinburgh process of immediate 
distillation, and the colouring of the distillate by comp, tincture and lavender. 
En passant , it must be queried whether this maceration is beneficial, or whether 
it is not rather prejudicial to the distillate, as it has been shown that the leaves 
of cherry-laurel contain principles analogous, and that react upon each other, 
as do those in the bitter almond, i. e. an azotized body (amygdalin) is acted 
upon by a ferment (emulsion), and instantly essential oil, prussic acid, sugar, 
and formic acid result. This same reaction, or a modification of it, doubtless 
takes place on the addition of the bruised cherry-laurel leaves to water, or even 
when the leaves are smashed thoroughly alone, for the 65 per cent, of water 
they contain when fresh is quite sufficient to develop the reaction when the cells 
of the leaf are destroyed. 
Those engaged, or who have had any experience, in the distillation of essential 
oil of almonds well know that the longer the almond, when thoroughly disin¬ 
tegrated, is in contact with water, the less is the product in the distillate of 
essential oil, as water is very favourable to the oxidation of the oil into benzoic 
acid. 
As the oil of cherry-laurel is the same in constitution, if not in composition, 
as bitter almond oil, which it resembles in almost every respect, save the pro¬ 
portion of hydrocyanic acid it contains (which, in the specimen I examined, 
did not reach 2 per cent.), it may naturally be inferred that the product, after 
distillation with previous maceration, is deteriorated in value of essential oil, 
although, perhaps, not to an appreciable extent in prussic acid. 
Many experiments which I have made at intervals during the last eighteen 
months show that immediate distillation of thoroughly bruised leaves, as soon 
as in contact with water, gave always a distillate superior in fragrance and 
equal in hydrocyanic acid, and, in some cases, slightly in excess of the latter, to 
those made after twenty-four hours’ maceration. 
The main point, however, to which I would direct you is one of more import¬ 
ance,—the percentage of hydrocyanic acid obtained from leaves distilled at dif¬ 
ferent periods, and the variable state of the cherry-laurel waters as found in 
pharmacy at the present time. 
In distilling various specimens, I have always operated on leaves absolutely 
fresh, and not after having been kept a week or two, as some change takes place 
2 K 2 
