BOTANY. 41 
assafoetida, &c. Camphor is a solid oil, consisting of carbon, oxygen, and 
hydrogen. 
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, benzo, copal, lac, 
&e. 
CaourcHovc is found associated with essential oil and resins in the milky 
juices of plants. It is procured from various species of Ficus, Urceola, 
Siphonia, &c. Gurra Percua is obtained from a species of Isonandra, found 
in Singapore and Borneo. 
Oraanic Acips occur in great variety in vegetable juices. Thus citric 
acid is found in the fruit of the orange, the lemon, lime, &c. ; 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 ; 
hydrocyanie, in the laurel ; oxalic, in Oxalis; &c. 
ALKALorpDs, 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; &e. 
Cotorine Matrers are obtained from plants, either directly or by means 
of a species of fermentation. Yellow coloring matters are procured from 
Curcuma longa as turmeric, from the gamboge plant as gamboge, from the 
stigmata of Crocus sativa as saffron, &c.; also from Reseda luteola (Weld) 
and from some lichens. The principal reds are alkanet from Anchusa; 
dragon’s blood from Dracena ; madder from Rubia tinctorum ; logwood from 
Heematoxylon; Brazil wood from Cesalpinia; 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 CircuLATiIonN 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 morganic, 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, wherg 
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 
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