OF THE CUTICLB OR EPIDERMIS. 17 



of this membrane continually peeling off from 

 tlic Birch, we see a resemblance to the 

 scales which separate from the shell of a 

 Tortoise. By maceration, boiling, or putre-* 

 faction, this part is separable from the plant 

 as well as from the animal, being, if not ab- 

 solutely incorruptible, much less prone to 

 decomposition than the parts it covers. The 

 vital principle, as far as wa can judge, seems 

 to be extinct in it. 



The cuticle admits of the passage of fluids 

 from Wiihin as well as from without, but in 

 a due and defmite proportion in every plant : 

 consequently it must be porous ; and the mi- 

 croscope shows, what reason would teach us 

 to expect, that its pores are ditlerent in dif- 

 ferent kinds of plants. In very succulent 

 plants, as Aloes, a leaf of which being cut 

 off will lie for many weeks in the sun without 

 drying entirely, and yet when partly dry 

 will become plump again in a few hours if 

 plunged into water, the cuticle must be very 

 curiously constructed, so as to admit of ready 

 absorption, and very tardy perspiration. Such 

 plants are accordingly designed to inhabit 

 hot sandy countries, where they are long 



c 



