90 FOOTNOTES FROM 



find, that the noble piles of architecture built by him as 

 if for eternity, though apparently as solid as the rock out 

 of which each individual stone had been hewn, and as 

 hard as the famous Roman cement which had resisted 

 the utmost efforts of Goth and Vandal, must yield in the 

 end to the slow but persevering assaults of the most 

 diminutive and contemptible vegetables, and be brought 

 back again by these apparently feeble agents to the 

 bosom of nature, out of which he had reared them with 

 such labour and skill. Here, indeed, we have an illus- 

 tration of that comprehensive saying of Melanchthon, 

 "The humble ones are the giants of the battle;" here 

 we have sermons in stones, lessons taught us by the life- 

 less lichens of the permanence of nature, and the never- 

 ceasing change and decadence attendant upon all the 

 works and possessions of man. 



The objects which lichens subserve when they are pro- 

 duced on rocks and ruins are thus sufficiently obvious : 

 but it is not so easy to determine their precise use when 

 growing on trees. It has been asserted by some writers 

 that so far from being beneficial, they are absolutely 

 prejudicial to the welfare of the forests in which they 

 abound. Such individuals, however, it is evident, totally 

 misapprehend the nature of these plants, for they extract 

 their nourishment principally from the medium with 

 which they are surrounded, and not from the matrix on 

 which they are developed, or to which they are attached. 

 The fungi are the only plants that are produced from 

 decay and corruption, and maintain their existence by 

 exhausting the vital juices of other plants. That lichens 

 are not injurious to the plants on which they grow, is 



