CHAPTER IV. 



OF THE CELrALAR INTEGUMENT. 



Immediately under tlie Cuticle we find a succulent 

 cellular substance, for the most part of a green colour, 

 at least in the leaves and branches, which is called by 

 Du Hamel the Enveloppe celhilab-e, and by Mirbel the 

 Tissii herbace. This is in general the seat of colour, 

 and in that respect analogous to the rete mucoswn^ or 

 pulpy substance situated under the human cuticle, 

 which is pale in the European, and black in the Negro ; 

 but we must carry the analogy no further, for these two 

 parts perform no functions in common. Du Hamel 

 supposed this pulp to form the cuticle ; but this is im- 

 probable, as his experiments show, when that membrane 

 is removed, that the Cellular Integument exfoliates, at 

 least in trees, or is thrown oiF in consequence of the 

 injury it has sustained, and a new cuticle, covering a 

 new layer of the same succulent matter, is formed under 

 the old one. Annual stems or branches have not the 

 same power, any more than leaves. 



But little attention has been paid to this organ till 

 lately, though it is very universal, even, as Mirbel ob- 

 serves, in Mosses and Ferns. The same writer remarks 

 that " leaves consist almost entirely of a plate of this 

 " substance, covered on each side by the cuticle. The 

 *' stems and branches of both annual and perennial plants 

 " are invested with it ; but i:i woody parts it is dried 

 '' up and reproduced continually, such parts only having 



