epidermis, iyo 



brane, capable of being partially detached but destitute 

 of organization. 



The glands, noticed by Saussure, are regarded by 

 Hedvvig as mere apertures, or pores, perforating the 

 pellicle that forms the epidermis. " They are con- 

 tained within a peculiar area, which is sometimes round, 

 sometimes oval, and sometimes rhomboidal. [Figs. 1 

 and 2 are designed to represent a magnified view of 

 these areas as exhibited by the garden pink and li- 

 ly.] They are generally oblong, though' they are of- 

 ten so much contracted as to change their form. The 

 areas communicate with one another by means of cer- 

 tain vessels originating in their circumference, and 

 forming part of the general net- work which is compos- 

 ed of two distinct but adherent layers. Finally, they 

 are regarded as being organs of perspiration, and their 

 peculiar areas, which consist also of two distinct but 

 not adherent layers, are regarded as forming recepta- 

 cles for perspirable matter."* 



The magnitude and number of these pores is unques- 

 tionably various in different plants, and by observing 

 how soon the branches wither when removed from 

 their original connexion, we can estimate the aggre- 

 gate number and size of the orifices, through which 

 their fluids escape. By observing also how soon the 

 faded branch revives after it is plunged into water, we 

 can determine the comparative magnitude and number 

 of those orifices, through which its fluids are absorbed • 

 and we shall find that while our aquatic vegetables with- 

 er in a few moments, owing to the rapid discharge of 

 their fluids, others are so constructed as to retain their 

 moisture several days. We shall likewise find that 



• Keith. 



