230 
NOTE ON CHERRY LAUREL WATER. 
That by adding one-fifth, to one-fourth of a drop of sul- 
phuric acid for every three fluid ounces of the distilled 
water, all the hydrocyanic acid it contains may be pre- 
served for at least one year. 
That this minute quantity of sulphuric acid cannot be 
injurious in the medical employment of this distilled water; 
and, that it is easy to understand, especially after having 
studied the published formulae for preparing this water, 
why therapeutists have not agreed as to its efficacy, since the 
hydrocyanic acid diminishes with age. Some may have 
made their trials with the water of the Codex of 1837, which 
is prepared by obtaining a quantity of product, by distillation, 
equal to the weight of the leaves employed, whilst others 
may have experimented with the water of the Codex of 1818, 
in which but one half as much water is obtained from the 
same quantity of leaves. Or it may have been that the waters 
were prepared by the formulae of foreign Pharmacopceias, 
which are a great deal more or less impregnated than that 
of the French Codex. The waters of some of the shops, 
contain little more than .0005 per cent., ten months after 
their preparation, 
[There appears to be much truth in the above observa- 
tions of M. Deschamps, and we have introduced them from 
the Journal de Pharmacies not so much from their bearing 
on the distilled water in question, which is rarely used in 
this country, as illustrative of the preservative influence of 
the mineral acids over solutions of hydrocyanic acid. 
The syrup of wild cherry bark contains prussic acid under 
the same circumstances as the cherry laurel water, ex- 
cept that it is associated with sugar, which may or may 
not retard the decomposition or loss of that acid. It becomes, 
therefore, a question worthy of examination, whether the 
addition of one drop of sulphuric acid to each pint of wild 
cherry syrup, will not prove useful, by increasing the sta- 
bility of the preparation. — Ed.] 
