39 



CHAPTER IV. 



OF THE ORGANIC SUBSTANCE OF PLANTS. 



Stmctore of tbe Roots, Stem and Leaves. Course of the sap. 

 Coroposilion aiul properties of water. Great number of organic 

 bodies. Wi«h!v ("Ire. Starch, Sugar, Gums. Composition of 

 tkcae bodi' r mutual relations. Organic substances 



•Mrtainin^ Sources of organic eleiuents: Caibua, 



Carbonic acid. Hydrogen, Oxygen, Nitrogen. 



SICnON L 8TKUCTUBE AND FUNCTIONS OF THE PLANT CI 

 ITS SEVERAL PARTS. 



The ditTerent external parts of plants are well 

 known, they consist of roots, stems, bark or epider- 

 mis, and leaves. 



The internal t'uactioBS of the roots 



are not so jh i as that of the other 



parts, owinfir to the dithculty ol knowing exactly what 

 or<iirs nni!.iirr.iiiti<I \t ;i »;lirir! <li>.tance beneath the 

 s ut little rootlets 



Hi i-wi> (iiii'< iion. ■mil fii iiii- i-Xiiriiit* COd of each IS 



a small b«jn<lle of soft, minute, white fibres. These 

 are all so mai ^ ' s for the nourishment of tbe 



ntem. If von - rw^t.s of a growing tree ia 



V wUl soon beoMM 



tins, to a coBskkraUt 



' T at s(>lection, as it is found 



'. i. .ire admitted to the exclusion, 



either partial or total, of others. Some coloring solu- 

 tions for instanoe, n- ' t , enter wi*' ' !ity and 



tm-r the ^irtiole Stti 'ft time, . rs are 



scarcely absorbed at an. 1 he same must, m a degree, 



