170 ACIDS, ALKALOIDS, AND COLOUEING MATTEES. 



various species of Ficus, as Ficus indica, after attacks of Cocci, and 

 from Aleuiites laccifera, and Eiythrina monosperma; Euphorbium, 

 from Euphorbia offlcinarum, antiquorum, and canariensis. 



Oaoutchottc is in some respects analogous to essential oils. It is 

 found associated with them and with resinous matters, in the milky 

 juice of plants. It is the inspissated juice of various species of Ficus, 

 as Ficus elastica, Kadula, elUptica, and prinoides, also of Urceola 

 elastica, Siphonia elastica, and Vahea gummifera. A kind of caout- 

 chouc, called gutta percha, imported from Singapore and Borneo, is 

 procured from Isonandra Gutta, one of the Sapotaceaa. The milky 

 juice of many orders of plants, as of Euphorbiaceee, Asclepiadaceae, 

 Apocynacese, Artocarpacese, and Papayacese, contains caoutchouc or 

 gum elastic. Some of these coloured juices are bland, as that produced 

 by the Cow-tree (Galactodendron utile) ; others are narcotic, as those 

 of Poppy and Chelidonium ; others are purgative, as Gamboge j others 

 diuretic, as Taraxacum. 



Oeganic Acids are produced by processes going on in living 

 plants, and exist in vegetable juices often combined with peculiar 

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

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

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

 of the apple, gooseberry, and mountain ash ; Tannic acid or Tannin, 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 specieg 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 in Prunus Laurocerasus, etc., 

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

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

 combination with lime in Ehubarb, and many species of Parmelia and 

 Variolaria. 



Alkaloids or Oeganic bases are azotised compounds found in 

 living plants, and generally containing their active principles. They 

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

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

 bark, the latter in pale bark; Morphia, Narcotin, Codeia, Thebaia, 

 and Narcein, occur in the juice of Papaver somniferum ; Solania is 

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

 nigrum, and Dulcamara ; Veratria exists in Veratrum Sabadilla and 

 album ; Aconitia in Aconitum Napellus ; Strychnia in Strychnos 

 Nux-vomica, Sancti Ignatii, Colubrina and Tieut^; Brucia also in 

 Nux-vomica or false Angustura bark ; Atropia in Airopa Belladonna ; 

 Beberia in Nectandra Eodiei j Piperin in Piper longum and nigrum ; 

 Emetina in Cephaelis Ipecacuanha; Caflfein (Thein and Guaranin) 

 in Coffea arabica, Thea Bohea and viridis, PauUinia sorbUis and 



