13 



CHAPTER III, 



OF THE CUTICLE OR EPIDERMIS. 



JbrYERT part of a living plant is covered with a skin 

 or membrane called the cuticle, which same denomina- 

 tion has been given by anatomists to the scarf skin that 

 covers the animal body, protecting it from the injuries 

 of the air, and allowing of due absorption and perspi- 

 ration through its pores. 



There is the most striking analogy between the 

 animal and the vegetable cuticle. In the former, it 

 varies in thickness from the exquisitely delicate film 

 which covers the eye, to the hard skin of the hand or 

 foot, or the far coarser covering of a Tortoise or Rhi- 

 noceros; in the latter, it is equally delicate on the parts 

 of a flower, and scarcely less hard on the leaves of the 

 Pearly Aloe, or coarse on the trunk of a Plane tree. 

 In the numerous layers of this membrane continually 

 peeling off from the Birch, we see a resemblance to 

 the scales which separate from the shell of a Tortoise. 

 By maceration, boiling, or putrefaction, this part is se- 

 parable from the plant as well as from the animal, 

 being, if not absolutely incorruptible, much less prone 

 to decomposition than the parts it covers. The vital 

 principle, as far as we can judge, seems to be extinct 

 in it. 



