OF THE BARK. 27 



be, according to M. Mirbel's theory, hard- 

 ened and dried Cellular Integument; but 

 they are rather perhaps that vascular part of 

 the Bark which once contained the secreted 

 fluid, or turpentine, so abundant in this tree. 



The bark of Oak trees twenty or thirty 

 years old, if cut and long exposed to the 

 weather, separates into many fine thin layers, 

 of a similar, though less delicate, texture 

 to the Lace Bark of Jamaica. All these 

 layers, in a living state, are closely connected 

 with each other by the cellular texture which 

 pervades the vegetable body in general, as 

 well as by transverse vessels necessary for the 

 performance of several functions hereafter to 

 be mentioned. 



In the bark the peculiar virtues or qualities 

 of particular plants chiefly reside, and more 

 especially in several of its internal layers 

 nearest to the wood. Here we find in appro- 

 priate vessels the resin of the Fir and Juniper, 

 the astringent principle of the Oak and Wil- 

 low, on which their tanning property depends, 

 the fine and valuable bitter of the Peruvian 

 Bark, and the exquisitely aromatic oil of the 

 Cinnamon. The same secretions do indeed 



