468 OPIUM 



and plastic ; when long kept, or artificially dried, it is hard, 

 and easily reduced to a brown powder, which is apt, unless 

 carefully preserved, to absorb moisture. When heated it 

 softens, and at high temperatures burns with a strong, 

 peculiar odour. Cold water dissolves about 60 per cent, 

 of a good dried specimen, and forms a red-brown solution, 

 including most of the active constituents. Rectified spirit 

 dissolves about 80 per cent., and forms a dark-brown 

 tincture, which includes all the active principles. Acids, 

 when strong, decompose opium, but when diluted are ex- 

 cellent solvents for it. The watery solution reddens litmus, 

 owing to the presence of meconic and other acids, and is 

 precipitated by vegetable astringents, salts of calcium, lead, 

 copper, and other metals. 



IMPURITIES. Inferior specimens of opium are distin- 

 guished by narrowly examining their consistence, texture, 

 colour, odour, and taste. They are sometimes dry, hard, 

 and resinous, or oleaginous and waxy ; their fresh fracture 

 devoid of the characteristic red tint and agreeable aromatic 

 odour ; while water and alcohol dissolve them imperfectly. 

 Of the several substances used for adulterating, the most 

 common are starch and molasses, the bruised leaves and 

 chips of the poppy, the juice, pulp, or extract of the prickly 

 pear, and opium from which the morphine has been ex- 

 tracted. Inorganic matters, such as sand, clay, and mud, 

 may be detected by inspection, especially if the specimens 

 be dried. But the official and most certain test of quality 

 or purity is the proportion of morphine. One hundred 

 grains of good opium should yield 9- 5 to 10' 5 grains of 

 anhydrous morphine ; but picked specimens have produced 

 22 per cent. 



COMPOSITION. Opium is a complex substance. Besides 

 15 to 25 per cent, of water, it contains 50 of gum, pectine, 

 wax, and albumin ; 2 to 6 of ash ; traces of an aromatic 

 volatile oil ; while combined with meconic, thebolactic, 

 phosphoric, and sulphuric acids are a number of alkaloids 

 in variable proportions, together amounting to about 20 

 per cent. The most important are morphine, codeine, 

 narcotine, and thebaine. There are also two neutral bodies, 

 meconin and meconiasin. 



