112 
ORIGINAL COMMUNICATIONS. 
made, by impregnating the water with the appropriate volatile 
oil, by trituration with magnesia. This is certainly the sim- 
plest and least expensive process for preparing them; and in 
many cases, the resulting article, in a medical point of view, is 
fully equal to that obtained by distillation; though this is not 
always the case, owing to the difficulty of procuring the essen- 
tial oils in a pure state. In other respects, however, medicated 
waters made in this manner are far inferior to those procured 
by distilling from fresh plants, and in some cases totally differ- 
ent products are obtained by the two processes. Thus it has 
been shown by M. Soubeiran, (Journ. de Pharm. xvi. 619,) 
that orange flower water, distilled from the flowers, and that 
made with the essential oil of these flowers, (neroli.) differed 
widely from each other in many important characters; as, for 
instance, in permanency ; the distilled water retaining its odour 
and other properties after exposure to the air, whilst the facti- 
tious article was speedily rendered inert. 
There are few pharmaceutic preparations whose nature is 
so little understood as the distilled waters, for though in some 
cases they may be nothing more than a diffusion of the vola- 
tile oil of the plant through water, it has not been satisfacto- 
rily shown whether this oil is merely in a state of infinite 
division in the vehicle, whether it undergoes certain changes, 
or lastly whether other principles may not be associated with 
it. In the case above cited, M. Soubeiran has proved that 
the latter is the case, the distilled water containing an aromatic 
body, which that made with the volatile oil does not. Again, 
the distilled waters of bitter almonds, peach kernels, &c. owe 
their principal medicinal properties to the presence of princi- 
ples which did not pre-exist in a formed state, but which were 
formed during the process by the combined action of the heat 
and water. 
Tinctura Opii. The different Pharmacopoeias of Europe 
and the United States agree very nearly in their formulas for 
the preparation of this important article, though at the first 
glance it would appear that the reverse is the case; their pro- 
portions are one part of opium to twelve parts of weak alcohol. 
