■i

4

Materia Me die a.

Part II.

made into an ointment with sixteen times its weight of axunge,has been used in the cure of psora.

AciDTJM CITRICUM CRYSTALLIS CONCRETUM. Dllb.

Citric acid crystallized.

The simple expressed juice of lemons is extremely apt tospoil, on account of the sugar, extractive, mucilage, and water,which cause it to ferment.

Various means have been proposed and practised, with theintention of rendering it less perishable, and less bulky. Thejuice has been evaporated to the consistence of rob ; but thisalways gives an empyreumatic taste, and docs not separate theextractive or mucilage, so that it is still apt to ferment whenagitated on board of ship in tropical climates. It has beenexposed to frost, and part of the water removed under theform of ice ; but this is liable to all the former objections, andbesides, where lemons are produced in sufficient quantity,there is not a sufficient degree of cold. The addition of aquantity of alcohol to the inspissated juice separates the muci-lage, but not the extractive or sugar. By means, however, ofScheele's process, as reduced to determinate quantities byProust, we can obtain the acid perfectly pure and crystallized.

It is now manufactured in this country, in large quantities,and sold under the name of Coxwell's Concrete Salt of Le-mons ; and a formula is given for its preparation, by the Lon-don college.

Acipenser. Pisces Branchiostegi, Cuvier.Sp. Acipenser Huso. Dub.

The Beluga, or Isinglas fish.Sp. Acipenser Ruthenus. Dub.

The Sterlet, or Caviar sturgeon,

Officinal —Isinglass.

IcHTHYOCOLLA. Dub.

Besides those mentioned by the Dublin college, isinglassis prepared from other species of Acipenser, especially A. stu-rio, the sturgeon, and A. steUatus, the serruga.

The preparation of isinglass is almost peculiar to Russia. Itis made in all places where the large species of sturgeon arecaught, as on the Dneipcr, the Don, and especially on the Cas-pian sea, also on the Volga, the Ural, the Oby, and the Irtysh.That prepared from the sturgeon is reckoned the best, andnext to it, that from the beluga. It also varies according to themode of preparation. On the Volga and Ural, the sounds arewatered while fresh, and dried to a certain degree. The outer