LECTURE 111. 



On the Organization of Plants. Of the Roots, Trunk*, 

 and Branches. Of their Structure. Of the Epider- 

 mis. Of the cortical and alburnous Parts of Leaves, 

 Flowers, and Seeds. Of the chemical Constitution of 

 the Organs of Plants, and the Substances found in 

 them. Of mucilaginous, saccharine, extractive, resin' 

 ous, and oily, Substances, and other vegetable Co?n- 

 pounds, their Arrangements in the Organs of Plants, 

 their Composition, Changes, and Uses. 



VARIETY characterises the vegetable kingdom, 

 yet there is an analogy between the forms and the 

 functions of all the different classes of plants, and on 

 this analogy the scientific principles relating to their 

 organization depend. 



Vegetables are living structures distinguished 

 from animals by exhibiting no signs of perception, 

 or of voluntary motion ; and their organs are either 

 organs of nourishment or of reproduction ; organs 

 for the preservation and increase of the individual, or 

 for the multiplication of the species. 



In the living vegetable system there are to be 

 considered, the exterior form, and the interior consti- 

 tution* 



Every plant examined as to external structure, 

 displays at least four systems of organs or some 

 analogous parts. First, the Roof, Secondly, the 



