152 



GROWTH OF TREES. 



sap or pulp, or the formation of new vessels, it dies, 

 and by all its moisture passing off into the younger 

 wood, the fibres shrink, and are ultimately reduced to 

 dust. The centre of the tree thus becomes dead, 

 while the outer portion' continues to live, and in this 

 way trees may exist for many years before they 

 perish. 



An interesting mode of comparing the infancy of 

 the oak with one of advanced age, is given by Ruricola, 

 in the Field Naturalist's Magazine. He hangs to a 

 piece of cork, a, an acorn, b } in a hyacinth glass, in 

 which it will germinate and grow to some height. 



