COMMON SWEET FLAG.

77

which were attached to it; the Iower surface has numerous dark points, sur-rounded by small light-coloured elevated circles, from which the roots arise.lheir taste is warm and bitter; their odour is aromatic. In Germany, therhizome is usually peeled before drying it (rhizoma decorticata); but the Opera-tion is unnecessary and wasteful. In this State the rhizome is erayish white andeasily pulverizable.

The rhizome should be gathered in spring or late in the autumn, and driedquickly.

The rhizome of the Yellow Water Iris (Iris Pseudo-acorus) is said to besometimes substituted for that of the true Acorus.

Comtosition —The fresh rhizome was analysed by Trommsdorf, (Gmelin,Handb.d. Chem. ii. 1339), who obtained the following results -.— Volatile oil, 0-1 ;soft resvn, 2-3; extractive, with a Utile chloride of potassium, 3-3; gum, withsome phosphate of potash, 5-5 ; starchy mattet (iike inulin), 1-6; ivoody fibre,21-5 ; and water, 65-7. Meissner found traces of copper in the ashes.

The active constituents are the oii, the resin, and the extractive.

Oil ofthe common sweetßag (called in the shops oleum calami aromatici) is obtained by dis-tilling the fresh rhizome with water. Its odour is similar to, though less agreeable than, thatof the rhizome. Its colour is yellow. It is bought by snuff-makers, so that it is used, I pre-sume, for scenting snuff. It is also employed in the preparation of aromatic vinegar (see vol. i.p. 355.)

_ Chemical Chakaotehibtics. —Iodine blackens the rhizome (especially whenit has been boiled), thereby indicating the presence of starch. The cold decoc-tion of the rhizome forms, with a Solution of iodine, the blue iodide of starch.Aceta e and d.acetate of lead, and protonitrate of mercury, cause precipitateswith the decoction. These precipitates consist principally of metallic oxides orsubsalts and the substance called extractive. Nitrate of silver produces a pre-cipttate {chloride of silver), which is insoluble in nitric acid, but soluble in ammo-nia. The decoction reddens litmus.

Piiysiological Effects. —It is an aromatic stimulant and mild tonic. Vogt(Lehrb. d. Pharmdkodyn, i. 454, 2'= Aufl.) arranges it with the excitantia vola-tilia, and regards it as approaching angelica root on the one hand, and casca-rilla and angustura barks on the other.

Uses. —It is rarely employed by medical practitioners, though it might befrequently substituted, with good effect, for the. more costly oriental aromatics.It is a useful adjunet to other stimulants and tonics. It has been employed incontinued asthenic fevers aecompanied with much prostration of strength andgreatly weakencd digestive power. For the eure of ague, the dried root pow-dered , s used b tho count , e ; n No rfoIk. (Sir J. E. Smith, Engl.

Jllora, ii. 158.) i« :- ■ " i - - • v ö

dependent on, an

viceable in gouty subjeets. It has also been used as a localformation of aromatic baths, poultices, and «iconditioned ulcers, &c. ^^^^^^^^^^^^^^^^

AD,iiNi ST RATlON._In powder, the rhizome may be given in doses of from ascruple to a drachm. lhe znfusion is perhaps the most eligible preparation : itis made by digesting gj. ofthe rhizome in gxij. of boiling water; the dose is twoor three tablespoonsful. The decoction is an objectionable preparation as theoil ofthe rhizome is dissipated by boiling. The tinäure (Ph. Bor.) is p'rocuredby digesting gij. of the rhizome in gxij. of spirit (sp. gr. 0-900); tho dose is ateaspoonful.

158.) It i s we n adapted for dyspeptic cases aecompanied with, oratonic condition ofthe digestive oraans, and is especially ser-

agent, viz. in theas an application to foul-