243.  Oxalis Acetosella.  Wood sorrel.  Herb.  L.—­In taste and medical qualities it is similar to the common sorrel, but considerably more grateful, and hence is preferred by the London College.  Boiled with milk, it forms an agreeable whey; and beaten with sugar, a very elegant conserve.—­Lewis’s Mat.  Med.

244.  Papaver Rhoeas.  Red poppy.  Petals.  L. E. D.—­The flowers of this plant yield upon expression a deep red juice, and impart the same colour by infusion to aqueous liquors.  A syrup of them is kept in the shops:  this is valued chiefly for its colour; though some expect from it a lightly anodyne virtue.

245.  Papaver somniferum.  Opium poppy.  Gum.  L. E. D.-Poppy heads, boiled in water, impart to the menstruum their narcotic juice, together with the other juices which they have in common with vegetable matters in general.  The liquor strongly pressed out, suffered to settle, clarified with whites of eggs, and evaporated to a due consistence, yields about one-fifth or one-sixth the weight of the heads, of extract.  This possesses the virtues of opium; but requires to be given in double its dose to answer the same intention, which it is said to perform without occasioning nausea and giddiness, the usual consequences of the other.

The general effects of this medicine are, to relax the solids, ease pain, procure sleep, promote perspiration, but restrain all other evacuations.  When its operation is over, the pain, and other symptoms which it had for a time abated, return; and generally with greater violence than before, unless the cause has been removed by the diaphoresis or relaxation which it occasioned.

The operation of opium is generally attended with a slow, but strong and full pulse, a dryness of the mouth, a redness and light itching of the skin:  and followed by a degree of nausea, a difficulty of respiration, lowness of the spirits, and a weak languid pulse.

With regard to the dose of opium, one grain is generally sufficient, and often too large a one; maniacal persons, and those who have been long accustomed to take it, require three or more grains to have the due effect.  Among the eastern nations, who are habituated to opium, a dram is but a moderate dose:  Garcias relates, that he knew one who every day took ten drams.  Those who have been long accustomed to its use, upon leaving it off, are seized with great lowness, languor, and anxiety; which are relieved by having again recourse to opium, and, in some measure, by wine or spirituous liquors.

Similar Plants.—­Papaver hybridum; P. Argemone.

246.  Pastinaca Opoponax.  Opoponax, or candy carrot.  Gum Opoponax.  L.—­ The juice is brought from Turkey and the East Indies, sometimes in round drops or tears, but more commonly in irregular lumps, of a reddish-yellow colour on the outside, with specks of white, inwardly of a paler colour, and frequently variegated with large white pieces.