MICROSCOPIC OBJECTS. 31 



Fig. 61. Transverse Section of the Wood of the Cork-Oak 

 Tree (Quercus Suber), x 120. Exogen. 



The large holes seen in this drawing represent the trans- 

 verse sections of the ducts of this wood; the other parts 

 represent the woody parenchymatous cells, placed amidst the 

 ordinary prosenchymatous tissue of the wood. The large 

 holes give the woods belonging to this genus, which may be 

 represented by this drawing, a distinctive character from those 

 of most of our British woods, their grain generally being 

 much closer (see figs. 68, 69, 70, &c.) . 



Oak is an extremely durable wood, and is, or rather was, 

 largely used in ship-building &c. 



Fig. 62. Longitudinal Section of Honduras Mahogany 

 (Swietenia Mahagoni), x80. Exogen. 



The ducts of this wood seem to be extremely large and 

 very loose in structure. They contain a large quantity of 

 resin, part of which, as left in the duct, may be seen on 

 referring to the drawing. The ordinary prosenchymatous 

 tissue is also of a rather looser structure than is generally 

 found in most other woods. 



