ALKALOIDS OF. Opium—the dried juice that exudes from incisions made in poppy heads while still growing on the plant— owes its well-known narcotic properties to certain organic bases or alkaloids. The number of these alkaloids at present known is seven ; their names are-1. Illorphine; 2. Codeine; 3. Thebaiee; 4. Paparcrine; Opianine ; 6. Narcotine ; 7. Narceine. They exist in opium chiefly in combination with 31zeone Amp, and associated with them are opianyi [3Incoxn], resinous matter, caoutehouc, fat, gum, volatile oil, lignin, and small quantities of inorganic salts. The following table exhibits the percentage composition of four varieties of Smyrna (the Nita) opium, analysed by 3Iiilder in the year 1836, and consequently before thebaine, papaverine, and opianine were rescued from the ill matter Called "gummy extractive :"— The morphia is however sometimes present to the extent of twelve, and in some French opium prepared in different parte of the Somme department even twenty to twenty-two, per cent. Constantinople opium varies somewhat, but is usually as rich in alkaloids as Smyrna opium, while Persian opium is generally poor in alkaloids, and Indian opium midway, in that respect, between the Smyrna and Persian varieties.
Separation of the opium prineipks from cads other.—Tho methods by which any single constituent of opium is extracted are tolerably easy; the isolation of each one, however, from the same specimen of opium is a matter of far greater difficulty, and can only be successfully carried out by working with Large quantities of raw materiaL Fortunately the operation is seldom or never necessary, and will only be given here as an illustration of the rolations which the principles bear to each other. The following outline of the method adopted, is abridged from Chemistry, vol. p. 277.
Three pounds of opium are exhausted with water ; from the In soluble residue eareetine may be extracted by digesting in acetic acid, precipitating with ammonia, and purifying with animal charcoal; from the evaporated infusion, neutralised with chalk, meconic acid is pre cipitated by chloride of calcium, and the mocourite of lime farther treated as described under MECONIC ACID ; the clear liquid filtered from the meconate of limo yields crystals of hydrochlorate of morphine on being concentrated ; farther concentration of the liquid just named causes hydrochlorates of morphine and codeine to crystallise out, from which codeine is dissolved out by ammonia and afterward), reprecipi tated by potash ; ammonia added to the black mother liquor filtered from the hydrochlorates of morphine and codeine precipitates thetaine and paparerine, which are subsequently separated from each other by baaio acetate of lead, while sarceinc and meconin remain in the am moniacal solution ; from the latter, narceine is precipitated by acetate of lead, and meconin then alone remains dissolved. Opianine has hitherto
only been found in Egyptian opium.
1. iforphine 2Aq.), Morphia, Morphina. This alkaloid derives its name from Morpheus, the god of sleep, in allusion to its narcotic properties. It was probably known during the 17th century, as Ludwig notices, in 1688, a substance called magistery of opium, pos sessing properties similar to those of the body in question. 31orphine is found only in plants of the poppy tribe [PAPAVER, in NAT. limp. Div.], and is generally combined with meconic acid, but sometimes with sulphuric acid.
Morphine may be extracted from opium in several ways. The London Pharmacopoeia' directs that the opium be thoroughly ex hausted with water, and chloride of lead added to the resultiug strained liquor until no more precipitate of meconate of lead is thrown down ; the filtrate is then evaporated to the crystallising point, the crystals of hydrochlorate of morphine purified from colouring matter by digesting with animal charcoal and recrystallisation, and morphine precipitated from the hydrochlorate by addition of ammonia.