THE NITROGEN COMPOUNDS IN PLANTS 153 



and also is smoked, chiefly by the Chinese. Opium contains 

 many alkaloids morphine about 9 per cent., narcotine about 

 5 per cent., and other alkaloids about i per cent. Morphine 

 exists in opium in the form of two soluble salts, so that 

 extraction with water removes all this alkaloid. Gregory's 

 method for the manufacture of morphia consists in extracting 

 the drug with water at about 40 Cent., mixing the liquor 

 with excess of calcium carbonate, and evaporating to a small 

 volume. Calcium chloride is added to a slight excess, the 

 liquid diluted, and a precipitate, consisting of resin and 

 calcium meconate, filtered off. On concentrating the liquid 

 the hydrochloride of morphine crystallizes out. This 

 is dissolved in water, the solution decolorized with charcoal, 

 and decomposed by ammonia, which precipitates the morphia 

 nearly pure. Further purification is effected by ether and 

 benzene. 



Cinchona (Peruvian Bark). The tree which yields this 

 bark is a native of Peru, and the value of the bark for curing 

 intermittent fevers was known to the American natives 

 before the conquest of Peru, but they concealed its value 

 for a long time. In 1638, however, the Countess Cinchon 

 obtained the use of this for the cure of ^ever, and subsequently 

 brought quantities of ground bark to Europe, where it was 

 known by the name of the " Powder of the Countess." 

 Subsequently it became known to the Jesuits, and was 

 usually called " Jesuit's Bark." Three kinds of bark are 

 commonly known, the pale bark, the yellow bark, and the 

 red bark. The cinchona trees are now cultivated in many 

 parts of the world, considerable quantities being grown and 

 manufactured in India under Government supervision. 

 The use of plain bark is no longer very large in medical 

 practice, being replaced by the purer drugs. The total 

 alkaloids of Peruvian bark are first extracted with water, 

 and dissolved for the most part. The cincho-tannates may 

 be dissolved by a dilute acid, or they may be decomposed 

 by mixing the bark with lime and water. Extraction 

 with dilute hydrochloric acid is not usually employed now. 

 On the large scale, finely powdered bark is mixed with lime, 



