CHAPTER III. 



THE STEM AND BRANCHES. 



Although even- member of the vegetable form, 

 from the minutest root to the most fragile flower, 

 have their epidermis, cellular integument, bark, 

 woody fibre, and medullary matter, yet as these are 

 most apparent in the stem and branches, they can 

 be commented upon most readily in tliis chapter, 

 devoted to the consideration of those vegetable 

 members. 



The first of these, the epidermis, is analogous to 

 the human cuticle, or scarf skin, being the external 

 envelope of the whole surface. It is commonly 

 ti'ansparent and smooth, sometimes hairy ; in other 

 instances hard and rugged, occasionally so abounding 

 -with silica or flint as to be employed as a polisher for 

 wood, and even brass. In every instance it is a net- 

 work of fibres, the meshes of which are filled ^^ith a 

 fine membrane. The epidermis appears to be de- 

 signed as a preservative from the injurious effects of 

 the atmosphere, to regulate the quantity of gaseous 

 matter and moistm'e respired, and as a shield from 

 the attacks of animals, &c. It is certainly devoid of 



