OF THE STRUCTURE OF WOOD AND HERBS. 



87 



in the wood is very distinctly marked, gathering in arched bands near two divisions 

 of me annual growth. 



MAPLE. A cross section of the firm wood of the Maple is presented in figure 

 135, highly magnified. The strong dark lines are the rays of cellular tissue, ema- 



Fio. 135. 



nating from the centre of the trunk of which this section represents a part. The 

 large oval openings are sections of the spiral vessels which run lengthwise through 

 the trunk, and the rest of the figure shows the true wood filled with minute pores, 

 whose size does not exceed the actual measurement of one twelve-hundredth of an 

 inch in diameter. 



DOGWOOD. -A magnified cross section of Dogwood is delineated in figure 136. 

 This wood is very hard and firm in its texture, and the smaller pores are much 

 more minute than those of the maple and other lighter woods. In the specimen 

 exhibited, a multitude of fine oval pores are seen scattered throughout the wood, 

 the largest of which does not exceed one two-thousandth of an inch in diameter,, 

 and the smallest is not more than one Ihrte-thousandih of an inch. 



