CHAPTER IV. 



TEXTURE OF VEGETABLES. 



When we reflect upon the vast variety of produc- 

 tions which the analysis of vegetables discloses to our 

 view, and that even the same plant presents substances 

 essentially different from each other ; it must be obvi- 

 ous that for each of these substances there is an appro 

 priate system of vessels. And when we examine the 

 transverse section of a woody stem, it presents sever- 

 al varieties of structure, distinguished from each other 

 by colour-taste— density and strength, embracing all the 

 different arrangements which are to be found in the grow- 

 ing plant, and some of them in their most perfect form. 

 It presents externally the BARK, composed of Epider- 

 mis — Cellular Integument and Cortical Layers ; it pre- 

 sents the WOOD, exhibiting, especially in old trees, 

 two distinct portions, which are readily distinguished 

 by their peculiar density and colour ; and in the cen- 

 tre of these it presents the PITH ; very abundant in 

 young shoots, but gradually disappearing with age. 



This is the arrangement which we find, and this we 

 shall adopt, in the prosecution of our enquiries respec- 

 ting the texture of vegetables. 



SECTION 1. 

 EPIDERMIS. 



The exterior covering by which every part of a liv- 

 ing plant is surrounded, is named itsCuticle or epidermis, 

 6 * 



