BOTANY. 41 



assafoetida. <fcc. Camphor is a solid oil, consisting of carbon, oxygen, and 

 hj'^drogen. 



Resins. These are either liquid or solid. The liquid or balsam of Tolu, 

 of Peru, of copaiva, Canada balsam, &.c. The solid are rosin, elemi, 

 sandarac, guiacum, labdanum, dragon's blood, storax, benzoin, copal, lac, 

 (fee. 



Caoutchouc is found associated with essential oil and resins in the milky 

 juices of plants. It is procured from various species of Ficus, Urceola, 

 Siphonia, (fee. Gutta Perch a is obtained from a species of Isonandra, found 

 in Singapore and Borneo. 



Organic xiciDS occur in great variety in vegetable juices. Thus citric 

 acid is found in the fruit of the orange, the lemon, lime, (fee. ; tartaric, in the 

 grape ; malic, in the apple ; tannic, in oak bark and nut-galls ; gallic, in the 

 seeds of mango ; meconic, in the juice of the poppy ; kinic, in Cinchona ; 

 hydrocyanic, in the laurel ; oxalic, in Oxalis ; (fee. 



Alkaloids, or vegetable alkalies, are nitrogenized compounds, found in 

 living plants, and generally containing their active principles. They occur 

 usually in combination with organic acids. Quinine and cinchonine are derived 

 from Cinchona or Peruvian bark ; morphine, narcotine, codeine, thebaine, and 

 narceine, from the poppy ; solanine, from the potato and other species of Sola- 

 num ; veratrine, from hellebore ; aconitine, from Aconitum ; strychnine and 

 brucine, from nux vomica ; atropine, from belladonna ; piperine, from Piper ; 

 emetine, from ipecacuanha ; caffeine, from coffee, tea, and Paraguay tea ; theo- 

 bromine, from the cacao ; (fee. 



Coloring Matters are obtained from plants, either directly or by means 

 of a species of fermentation. Yelloio coloring matters are procured from 

 Curcuma longa as turmeric, from the gamboge plant as gamboge, from the 

 stigmata of Crocus sativa as saffron, (fee. ; also from Reseda luteola (Weld) 

 and from some lichens. The principal reds are alkanet from Anchusa ; 

 dragon's blood from Dracaena ; madder from Rubia tinctorum ; logwood from 

 Hffimatoxylon ; Brazil wood from Cassalpinia ; carthamine from Carthamus ; 

 archil and litmus from Roccella tinctoria, one of the lichens. The principal 

 blue is indigo, from various species of Indigofera. 



C. The Circulation and Elaboration of Fluids in Plants. 



The entrance of liquid matter into the plant is effected mainly through 

 the roots. The extremities of these are covered by a very delicate 

 membrane, which permits the imbibition of liquids with great rapidity. 

 The matter thus absorbed by the roots consists of water holding various 

 matters, chiefly inorganic, in solution ; and this is carried up, partly by 

 capillary attraction, partly by endosmosis. This ascending- sap passes up 

 through the vessels and cells of the stem, and thence into the leaves, where 

 it is elaborated and returned as descending- sap through the bark, a small 

 portion reaching the roots, there to be excreted, or else stored up for 

 purposes of future nutrition. Gaseous matters are also taken up by the 



41 



