The concrete milk-juice of Lactuca virosa.

Characters. - In sections of plano-convex, circular cakes, or in irregular, angular pieces, externally grey brown or dull reddish-brown, internally whitish or yellowish, of a waxy lustre; odour heavy, somewhat narcotic; taste bitter. It is partly soluble in alcohol and ether, and when triturated with water it yields a turbid mixture.

Composition. - Its chief ingredient is a bitter substance - lactucin.

Preparations.

Dose.

Extractum Lactucarii Fluidum......................................................

3-60 min.

Syrupus Lactucarii.........................................................................

2 fl. dr.

Dose. - Of lactucarium, 5-30 gr.

Action and Use. - Lettuce has a somewhat soporific action, and the extract has been used for sleeplessness. Lactucarium is used instead of opium to allay cough, quiet nervousness, and induce sleep in cases where, from idiosyncrasy, opium is not borne.