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CHAPTER ill. 



OF THE CUTICLE OR EPIDERMIS. 



Every part of a living plant is covered with a skin or 

 membrane called the cuticle, which same denomination 

 has been given by anatomists to the scarf skin that cov- 

 ers the animal body, protecting it from the injuries of 

 the air, and allowing of due absorption and perspiration 

 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 Rhinoceros ; 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 wliich 

 separate from the shell of a Tortoise. By maceration, 

 boiling, or putrefaction, this part is separable from the 

 plant as well as from the animal, being, if not absolutely 

 incorruptible, much less prone to decomposition than 

 the parts it covers.(2) The vital principle, as far as wc 

 can judge, seems to be extinct in it. 



(2) [The durability of the epidermis may every year be ob- 

 served in our woods, where cylinders of birch bark are tound in 

 a state of perfect preservation, long after the wood within them 

 has decayed."] 



