224 ANATOMY AND I'll YSIO1.OC; Y ul- PLANTS. 



to their bodies, called the cuticle or scarf-skin, so in 

 vegetables, we detect an external envelope or integu- 

 ment, extending over their whole surface, called the 

 epidermis or cuticle. 



In the currant-bush, the epidermis is very readily discernible, 

 being that part which is constantly peeling off from the older 

 branches. It may also very easily be detected in most plants by 

 maceration, boiling, or putrefaction ; being, if not absolutely incor- 

 ruptible, much less prone to decomposition than the parts it covers. 



19. Although the epidermis is extended over the 

 whole surface of the plant, it is not of equal consist- 

 ence thronghout. 



In the root and trunk, it is a tough and leathery membrane, or it is 

 a crust of considerable thickness, forming a notable portion of HIP 

 bark, and assuming some peculiar shade of colour which it seems to 

 acquire from age; while in the leaves, flowers, and tender shoots, it 

 is a fine colourless and transparent film not thicker than a cobweb. 



20. Du Hamel describes the epidermis as being 

 formed of a multiplicity of fine and delicate fibres, 

 placed in a parallel direction, and inosculating at regu- 

 lar intervals, or united by means of small and lateral 

 fibres so as to constitute a net-work, the meshes of 

 which, are filled up with a thin and transparent pellicle. 

 Throughout the whole cuticular surface, he relato, 

 every part is pierced with pores, which permit the 

 mouths of the absorbing, transpiratory and air vessels to 

 open to the air. 



Comparetti also describes it, as composed of fibres interwoven so 

 as to form hexagonal meshes, the areas of which, are filled up with 

 opaque or diaphanous vesicles, inflated as if extended with air or 

 water, and having a small black point in the centre. 



