32 
SELECTED ARTICLES. 
mouths of demijohns, which is sometimes enveloped with a 
small piece of flannel, to prevent the finer particles from pass- 
ing through. The ingredients, after having been well bruised, 
are introduced and kept in their place by a perforated earthen 
sphere or plate, such as generally accompany infusion pitch- 
ers. A quantity of water, equal to the desired product, at 
about the temperature of 1S0°, is now passed through the in- 
gredients, and the operation is repeated until it appears satu- 
rated; upon which it is set aside, and another portion of hot 
water used in like manner, until the product is but slightly 
colored. The displaced liquids are now evaporated in a well 
tinned copper dish to the quantity indicated. 
I have been thus minute in describing the peculiarities of 
this apparatus, as we have found it well adapted to the pre- 
paration of mel scillse c, syr. sarsse., syr. rhei et sennse, syr. 
rhei, &c. After several years experience in the preparation 
of the last mentioned syrups, according to the improved for- 
mula which I have published in the fifth volume of the Jour- 
nal of Pharmacy, page 33, I would confidently recommend it 
as a substitute for that of the Pharmacopoeia, as it is not apt to 
ferment, and the spirit used as a solvent for the rhubarb, &c, 
is evaporated. 
Jicidum Hydrocyanicum. The presence of a small quan- 
tity of cyanuret of mercury seems to be necessary to the pre- 
servation of the acid hydrocyanic of the Pharmacopoeia, as 
I have discovered that when solution of the cyanuret of 
mercury is super-saturated with sulphuretted hydrogen, it 
commences to precipitate carbon a few hours after its separa- 
ration from the sulphuret of mercury. After much experi- 
ence in its preparation, according to the above process, I have 
resorted to the process of Gay Lussac, described in the Dub- 
lin Pharmacopoeia, using half the amount of water ordered, 
and diluting the product with alcohol, to form a solution equal 
in strength to the officinal formula. No change has ever been 
discovered in this preparation. 
Maryland Med. and Surg. Journ. Jan., 1840. 
