THE TREMBLING POPLAR, OR ASPEN. 169 



leaves, and is to be accounted for by reference to natural 

 causes ; and though, he fails to discover the purpose of 

 this peculiarity in structure, he is satisfied with observing 

 a new instance of creative power, and prefers to confess 

 his ignorance of design rather than be indebted to Nature 

 for evidence which Eevelation alone can aiford, and which 

 God's Holy Spirit alone can make efficacious. 



The Aspen does not generally attain so large a size as 

 the Black Poplar, though there are specimens in existence 

 seventy or eighty feet high. Evelyn says, that "the 

 Aspen thrusts down a more searching foot " than that 

 tree, " and in this likewise differs, that he takes it ill to 

 have his head cut off ; " meaning, that the roots extend to 

 a great distance, and that the branches are impatient of 

 pruning. The roots, however, do not descend far beneath 

 the surface, and are remarkable for sending up numerous 

 suckers, which, if the tree be planted in a lawn or garden, 

 are very troublesome, and require to be eaten or mowed 

 down. It is not a long-lived tree, beginning to decay 

 internally when about sixty or eighty years old. 



The bark of the Aspen is said to be a favourite food 

 of the beaver, and its leaves are greedily devoured by 

 many domestic as well as wild animals. The timber is 

 used for nearly the same purposes as that of the other 

 species. As fire- wood it burns brightly, but rapidly, 

 giving out but little heat. 



As an ingredient in the landscape, the Aspen presents 

 the most pleasing appearance in situations where the 

 playful change of its foliage is thrown out by a dark 

 background. 



A chemical principle, called populine, has been extracted 

 from the bark and leaves of the Aspen, which has a sweet 

 taste like that of liquorice, and crystallizes in the form 

 of delicate white needles. Its properties are but little 

 known. 



