Spec. Plant Willd.iii. 1523. Cl. 19. Ord. 1. Syngenesia sequalis. Nat. ord. Compositae. G. 1404. Receptacle naked. Calyx imbricate, cylindrical, with a membranous margin Pappus simple, stipitate. Seed even. Species 1. L. sativa. Garden Lettuce. Plackwell, t.8. Species 12. L. virosa. Strong-scented Lettuce. Med. Pot. 3d edit.

75.t.31. Smith, Flora Brit. 819.

1 An excellent tooth-powder may be composed by mixing one part of finely powdered ratanhy-root with three parts of powdered charcoal.

1. Lactuca sativa.1

Officinal. Lactucarium, Lond. Lactuca sativae herba; Lactucarium, Edin. Lactuca sativa, herba, Dub. The herbaceous part and inspissated juice of the Garden Lettuce.

Syn. Laitue(.F.), Lattich (G.), Lataw Gewoone salade (Dutch), Lattuca(I.), Lechuga (S), Khasky (Arab.).

This species of lettuce is cultivated almost generally over Europe. The root is fibrous; and sends up a corymbose stem, which sometimes rises three feet in height. The leaves are roundish, obovate, or cordate, shining, crisped, rugose, irregularly plaited, and of a yellowish-green colour; but the plant is so well known as to require no description. When it is in flower, the slightest touch on the pedicles occasions the exudation of drops of a white, opaque, milky-looking fluid. The leaves and stem, immediately under the cuticle, contain a secreted juice, which is pellucid and colourless when in the vessels of the plant, but becomes milky when first exposed to the air, and afterwards acquires a brownish colour, resembling that of East Indian opium. This is the lactucarium2 of the Edinburgh college. The best method of procuring it, as first suggested by Mr. John Young, surgeon in Edinburgh, is to cut off the top of the stem, when it is in flower, about a foot above the ground, and to absorb the milky juice that exudes by means of a moist sponge, from which it can be again compressed into a proper vessel • to be inspissated.

But, as the cut surface soon ceases to bleed, another slice must be taken under the first; and this may be repeated as long as the fresh-cut surface will yield the juice. The process may be repeated two or three times a day. This juice is also collected upon wove cotton, about half a yard square, as proposed by Dr. Probart; and the impregnated cotton thrown into water, which is afterwards strained and evaporated. The same gentleman prepares an extract, by macerating the stalks and leaves in water, to extract the juice which concretes in the bark of the stems and in the old leaves after the plants have flowered and the leaves begin to turn yellow. But this extract is a much less powerful preparation than the lactucarium.

Theophrasti. This name was imposed by Dr. Duncan, sen. who first suggested its use as a narcotic. Vide Obs. on Pulmonary Consumptions, by A. Duncan, M. D. Appen. p. 162. The French call it thridace, from

lettuce; but this is the inspissated juice of lettuce, not the lactucarium of the elder Duncan. M. Robi-net has proposed to make a syrup of it, by adding to the expressed juice of the plant, just before it flowers, double the weight of sugar. He calculates that j, of this syrup contains six grains of the extract,

Qualities.-Lactucarium has the colour, and, in some degree, the taste and odour, of opium. Distilled water dissolves the greater portion of it; and the clear solution is of a deep brown colour; but Ganzel and others who have examined it obtained no morphia. It contains extractive, resin, and mucilage; and Dr. John states, that caoutchouc also is one of its components.

Medical properties and uses.-Lactucarium has been pro-prosed as a substitute for opium by Dr. Cox, of Philadelphia; but its value as a narcotic has been more lately examined by Dr. Duncan, senior, who conceives it to be particularly well adapted for allaying the cough in phthisis pulmonalis; and his opinions have been confirmed by the experience of many other respectable practitioners. The hypnotic influence of lettuce was known to Dioscoridis, and Galden proved its efficacy in his own person, and eat a lettuce every night to procure sleep. That of lactucarium has been well ascertained : and it undoubtedly proves useful as a soporific1, where, from peculiar idiosyncracy, or other causes, opium cannot be taken. The dose is from gr. i. to grs. vj. in the form of a pill: or, of a tincture made with one ounce of lactucarium and a pint of diluted alcohol, from ten to sixty drops may be taken.

Officinal preparation.-Succus spissatus Lactucae sativae, E.

2. Lactuca virosa.2

Officinal. Lactucae virosae herba, Edin. Dub. Strong scented Lettuce-leaves.

Syn. Laitue vireuse (F.), Wilder lattich (G.), Stinkende salade (Dutch), Stinkende laktuk (Dan.), Lattuca Salvatica (I.), Alface brava (Portug.).

This is an indigenous biennial plant, found growing on the banks of ditches and borders of fields, flowering in July and August. The stalk rises about three feet in height, erect, slender, prickly below, smooth above, round, panicled, and not very leafy. The leaves are rather smooth and toothed, the lower ones numerous, obovate, undivided; those of the stem smaller, often lobed, amplexicaule, with the midrib beset with prickles on the under side. The bractes are cordate and pointed. The flowers are numerous, compound, of a sulphur yellow colour, on short peduncles, furnished with small scaly leaves, and one at the base of each. The calyx is oblong, and composed of small lanceolate scales; and the corolla consists of florets scarcely longer than the calyx. The seeds are elliptical, compressed, striated, black, and furnished with a stipitate, scabrous pappus.

1 I have always found that when I eat lettuce to supper it acts as a soporific.

Dioscoridis.

The leaves and stem contain a white opaque juice under the cuticle, that abounds more copiously when the plant is in flower; at which time, therefore, they should be gathered, and the juice immediately expressed.

Qualities.-The odour of the leaves is heavy and fetid, resembling in some degree that of opium; their taste is bitter and acrid : qualities depending on their milky juice.

Medical properties and uses.-The expressed juice is narcotic and diuretic (see Preparations and Compositions). Dr. Schelinger of Frankfort has found it useful in angina pectoris1; and Dr. Toel has used it in combination with foxglove in hydrothorax accompanying disease of the heart.2 The leaves themselves are not used.

Officinal preparation.-Succus spissatus Lactucae virosae, E.