26 THE BAEK. 



very readily examined in a branch of the Cherry of one year's 

 growth. The epidermis will readily peal off, tearing trans- 

 versely. The cellular integuments may then be easily separated 

 from the subjacent liber. The two layers of the bark are each 

 formed every year, and of course the thick bark of old trees is 

 made up of alternate layers of cellular integuments and liber. 

 From the enlargement of the stem, and the internal formation 

 of bark, the outer layers become distended and broken, and 

 thereby produce the rugged appearance of some old trees ; and 

 the jiiinual peeling off of the bark of the Sycamore, which, from 

 the flight cohesion of the different layers, falls off as soon as 

 broken, prevents its forming longitudinal ridges like those of 

 the Oak and Pine. 



47. The liber is composed of woody fiber and cylindrical ves- 

 sels, a modification, undoubtedly, of the spiral. These together 

 form the strong fibers, which compose the net-work of this part 

 of the bark. The fibers of the liber, from their tenacity and 

 interlacing, are often made materials for use. The bark of the 

 flax and hemp consists of these fibers, and when twisted to- 

 gether constitute the cordage, thread, and cloth which are manu- 

 factured from these plants. The fibers are sometimes so closely 

 and firmly interwoven as to be used as a substitute for manu- 

 factured fabrics for clothing, with no other preparation than that 

 of separating and flattening the layers. Jamaica and the 

 Sandwich Islands afford examples of these productions. A 

 beautiful lace is obtained by the natives of the Pacific and West 

 India Islands, from the liber of different trees of the Mezerium 

 tribe. Cordage also is manufactured from the liber of trees of 

 the same family ; and our own Dirca, did it grow to sufficient 

 magnitude, might afford beautiful examples of the same kind 

 of nature's manufacture. From the liber of the Daphne bohlua 

 of Nipal, a very soft, beautiful paper is said to be manufactured. 

 The liber of trees, before the invention of paper or parchment, 

 was stripped into layers, flattened and cemented into leaves, 

 which formed books ; and it is from this circumstance that it 

 derives its name. The Russians also manufacture mats, which 

 bear their name from a species of the Tillia (Linden-tree). 



48. The cellular integument is not without its uses, deriving 

 its value, too, from its peculiar structure. It is the immense 

 development of this integument that forms cork, so extensively 

 employed for various useful purposes : and it is the development 

 of the same material in this part of the bark, that constitutes 



47. Of what is the liber composed ? What use is made of it ?— 48. Of 

 what use the cellular integument? 



