VEGETABLE ALKALIES. 119 



gar of lead) ; of copper (verdigris) ; and many others, which 

 are useful in the arts. 



8. Malic acid {C''H2O4=60) is obtained from the juice of 

 apples, barberrieSj plums, elder-lierries, currants, strawberries, 

 raspberries, etc. It is distinguished from the preceding acids, 

 by forming soluble salts with lime. 



9. Pnissic acid (C2NH=27) is obtained by the distillation 

 of laurel leaves, from the stones of the peach, cherry, and bit- 

 ter almonds. This is the most violent poison with which we 

 are acquainted. 



The above are only a few of the vegetable acids. They impart 

 to fruit that tart, pleasant taste which forms their distinguishing 

 characteristic. 



II. Alkcdies. This class includes about thirty-seven sub- 

 stances, all discovered since 1817. Those plants which are 

 remarkable for their poisonous or medicinal properties, contain 

 an alkaline principle. Those most important in this connec- 

 tion are Morphina, Narcotina, Cinchonina, Quinina, Strychni- 

 na, Emetina, Nicotina, Conicina, Solanina, Parillina. They are 

 compounds of hydrogen, oxygen, carbon and nitrogen ; and 

 their composition will be indicated by symbols, as in other 



1. Morphina {C^'^W^'NO^=2S4l) is the narcotic principle 

 of opium, and constitutes about -^\ of its weight. It is a well- 

 known poison, of an astringent bitter taste. It is used in medi- 

 cine to allay pain. When opium has been administered as a 

 poison, a skilful chemist will detect a single grain of the mor- 

 phina in 700 grains of water. It is contained in the capsule of 

 the poppy, from which it is generally obtained. It combines 

 with a great many organic and inorganic acids ; and the salts, 

 thus formed, are used extensively in medicine. 



2. J^arcotina (C^OH^ONOi^) is found in opium. It is not in- 

 jurious to man, but fatal to dogs ! 



3. Cinchonina (C20H'2NOl^=158) is found in Peruvian bark 

 {cinchona nitida, or condaminea), and imparts to it its value as a 

 medicine. It has a peculiar bitter taste, which is not perceived 

 at first, in consequence of its insolubility. It crystallizes in deli- 

 cate prismatic needles, or in white translucent tufts ; and, by 

 uniting with acids, forms a great number of organic salts. 



4. quinina [C^^^^N 0^=162) is also foimd in connection 

 with Cinchonina and is used for a similar purpose. The std- 

 phjte of quinina is manufactured on a large scale, and sold as 



Quinine. It is intensely bitter, and is of great value in certain 

 diseases. 



