ACIDS, ALKALOIDS, AND COLOURING MATTERS. 149 



tree (Galactodendron utile); others are narcotic, as those of Poppy 

 and Chelidonium ; others are purgative, as Gamboge; others diuretic, 

 as Taraxacum. 



320. Organic Acids are produced by processes going on in living 

 plants, and exist in vegetable juices combined often with peculiar 

 bases and alkaloids. Thus, Citric acid occurs in the fruit of the orange, 

 lemon, lime, red currant, &c. ; Tartaric acid, in the juice of the grape, 

 and in combination with potash in tamarinds ; Malic acid, in the fruit 

 of the apple, gooseberry, mountain ash ; Tannic acid or Tannine, in 

 oak bark and nut-galls ; Gallic acid, in the seeds of Mango ; Meconic 

 acid, in the juice of Papaver somniferum ; Kinic acid, in the bark of 

 various species of Cinchona. Besides these, there are numerous others, 

 which are characteristic of certain species or genera. To these may 

 be added Hydrocyanic acid, as found hi Prunus Laurocerasus, &c., 

 and Oxalic acid, which exists in combination with potash in Rumex 

 acetosa, and Acetosella, Oxyria reniformis, Oxalis Acetosella, in the 

 fluid in the pitcher of Nepenthes distillatoria; and in combination with 

 lime in Rhubarb, and many species of Parmelia and Variolaria. 



321. Alkaloids or Organic bases are azotised compounds found in 

 living plants, and generally containing their active principles. They 

 occur usually in combination with organic acids. Quinine and Cincho- 

 nine exist in the bark of Cinchona, the former predominating in yellow 

 bark, the latter in pale bark; Morphine, Narcotine, Codeine, Thebaine, 

 and Narceine, occur in the juice of Papaver somniferum ; Solanine is 

 an alkaloid found in many species of Solanum, as Solanum tuberosum, 

 nigrum, and Dulcamara ; Veratrine exists in Veratrum Sabadilla and 

 album ; Aconitine in Aconitum Napellus ; Strychnine in Strychnos 

 Nux-vomica, Sancti Ignatii, Colubrina and Tieute ; Brucine also in 

 Nux-vomica, or False Angustura bark ; Atropine in Atropa Bella- 

 donna ; Bebeerine in Nectandra Rodiei ; Pipeline in Piper longum 

 and nigrum ; Emetine in Cephaelis Ipecacuanha ; Caffeine (Theine 

 and Guaranine) in Coffea arabica, Thea Bohea and viridis, Paullinia 

 sorbilis, and Ilex paraguayensis ; Theobromine in the seeds of Theo- 

 broma Cacao or chocolate ; besides numerous others of less import- 

 ance. These Alkaloids are often found in plants having poisonous 

 properties. 



322. Colouring matters are furnished by many plants, either directly 

 or by a process of fermentation. Yellow colouring matters are pro- 

 cured from the roots of Curcuma longa or Turmeric, from the pulp 

 surrounding the seeds of Bixa orellana (arnotto), from the stem of the 

 Gamboge plant (Hebradendron Cambogioides), and various species of 

 Garcinia,as Garcinia Cambogia and elliptica, from the flowers of Cartha- 

 mus tinctorius (safflower), from the stigmata of Crocus sativus (saffron), 

 from a kind of Mulberry (Morns tinctoria), from Reseda Luteola (weld), 

 and from some Lichens, as Parmelia parietina (parietin or chryso- 



