OF THE CUTICLE OR EPIDERMIS. 15 



growing part is deprived of it, the greatest mischiefs 

 ensue. It forms in the Vegetable, as well as the Ani- 

 mal, a fine but essential barrier between life and de- 

 struction. 



Some have imagined that the cuticle gave form to 

 the vegetable body, because it sometimes beinw over 

 tight causes contractions on the stem of a tree, as in 

 the plum or cherry, and because it is found to be 

 cracked wherever an unnatural excrescence is produced 

 on the bark. No doubt the cuticle is formed so as to 

 accommodate itself c-nly to the natural growth of the 

 plant, not to any monstrosities, and those lumps cause 

 it to burst ; just as it happens to ripe fruits in very wet 

 seasons. Their cuticle is constructed suitably to their 

 usual size or plumpness, but not to any immoderate 

 increase from too great absorption of wet. If the cuti- 

 cle be removed from any part, no swellingfollows, as it 

 would if this membrane only kept the tree in shape. 



The extension of the cuticle is astonishing, if we 

 consider that it is formed, as Grew well observes, on 

 the tenderest embryo, and only extended during the 

 growth of the plant, and that it appears not to have 

 any connexion with the vascular or living part of the 

 vegetable body. But though so accommodating in 

 those parts where it is wanted, on the old trunks of 

 most trees it cracks in every direction, and in many is 

 entirely obliterated, the old dead layers of their bark- 

 performing all the requisite offices of a cuticle. 



M. Mirbel indeed, though he admits the importance 



