Extractum Sarzae. Lond. Extractum Sarsa-parilla, Dub. Extract of Sarsaparilla

"Take of sarsaparilla root, sliced, two pounds and a half; boiling distilled water, two gallons. Macerate for twenty-four hours, then boil down to a gallon: strain the solution while it is hot, and evaporate it to a proper consistence."

The experiments of the late Mr. Pope, Mr. Battley, and M. Robinet, have demonstrated, that the red, or, as it is termed, Jamaica sarsaparilla yields a much larger quantity of extract than any of the other species of sarsaparilla. It also appears from Mr. Pope's experiments, "that by submitting the root, cut transversely to the action of steam or of distilled water, at a temperature somewhat below boiling, an elegant, soluble extract may be obtained, containing all the virtues of the plant, not liable to decomposition, and applicable to the various purposes of extemporaneous prescription1;" whilst, by the method ordered in the above formula of the London College, an insoluble, inefficacious extract only is obtained.

When properly prepared, without heat, this extract possesses all the medicinal virtues of the root; but prepared according to the above formula it has little to recommend it to practice. The dose is from grs. x. to 3 j., dissolved in the decoction, or given in the form of pills.

Extractum Sarsaparillae Fluidum. Dub. Fluid Extract of Sarsaparilla

"Take of root of sarsaparilla, sliced, one pound; water, twelve pints. Boil for an hour, and pour off the liquor. Then add twelve pints more of water, and repeat the boiling and effusion. Let the fluid be strongly expressed from the residuary matter. Set aside the mixed decoctions until the faeces subside; then evaporate the mixture, by continued ebullition, to thirty ounces, and add two ounces of rectified spirit.

This extract, as it is termed, possesses no advantages over the ordinary decoction, except for the facility of preparing extemporaneous prescriptions. It is less active than the com-mon extract

Extractum Stramonii. Lond. Dub. Extract of Thorn Apple

"Take of thorn apple seeds, fifteen ounces; boiling distilled water, one gallon. Macerate for four hours in a lightly covered vessel near the fire; then take out the seeds; bruise them in a stone mortar, and put them again into the liquor. Then boil to four pints, and strain the decoction whilst it is hot. Finally, evaporate it to a proper consistence."

The medicinal powers of this extract are less to be depended

1 Medico-Chirurg. Trans, vol. xii. p. 345.

on than those of a tincture prepared with ij. of the herb, and f xvj. of proof spirit. The dose of the extract is half a grain to two grains, in the form of pills.

Extractum Nucis Vomicae. Dub. Extract of Nux Vomica

"Take of rasped nux vomica, eight ounces; proof spirit, two pints. Digest for three days in a close vessel; strain the fluid, and express strongly the residuum: to this add a pint and a half of proof spirit; digest for three days, and express the residuum. The mixed liquors being consumed by distillation to one fourth, reduce to a proper thickness.

"The extracts while thickening should be frequently stirred. They may be reduced to a proper thickness in a medium heat by the aid of steam. The process ought to be conducted so as to prevent as much as possible the contact of the air: the softer extract may be sprinkled with rectified spirit."

The object of this process is to obtain the strychnia without decomposition. In our opinion, it is preferable to employ the strychnia itself; and it can be procured with very little more trouble, and not more expense. The strychnia may be dissolved in alcohol; and by this means the dose may be accurately determined; but it is still better to give it in the form of acetate by dissolving it in a given quantity of distilled vinegar.

Besides the strychnia, this extract contains a bitter principle, a resinous substance, a gummy matter, and a peculiar acid.

The dose of the extract is from half a grain to two grains.