Page:An introduction to physiological and systematical botany (1st edition).djvu/57

 Rh be, according to M. Mirbel's theory, hardened 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 appropriate vessels the resin of the Fir and Juniper, the astringent principle of the Oak and Willow, 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,