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than a very small portion of what it shelters. If there 

 is the slightest furrow in the surface, and moisture can 

 lodge there, some little moss or lichen finds it out 

 and grows, even while the powers of the tree are still 

 vigorous. Then there is an insect in every bud, which, 

 as that awakens in the spring, will awaken too in 

 order to feed upon it. The little twigs are enclosed 

 with the eggs of the lacquay moth (lasiocampa neustria) 

 in a most perfect spiral, united by a cement that not 

 only defies the weather, but which, while the insects 

 continue there, can with difficulty be divided with a 

 knife, but when the purpose of nature is effected, and 

 the insects have come out, the cement dissolves, and 

 the little cells mingle with the general store of matter. 

 Every chink in the bark too, has its inhabitant, and 

 not a few are lodged in the wood in artificial cells. 

 This is remarkably the case wherever there is decay ; 

 for the soft heart of a hollow tree may be seen drilled 

 through and through by the larva of beetles, while the 

 wood that is vigorous is untouched. When, indeed, 

 we perceive that those insect productions, whether they 

 take place in an animal or a vegetable, are always at- 

 tended with, if not preceded by, decay or putrefaction of 

 some kind or other, we may cease to wonder that men, 

 before they had begun to find natural causes by con- 

 tinued observation, attributed the origin of those animals 

 to putridity ; for so intent is nature in preventing any 

 thing from lying idle, that no sooner does any particle 

 of matter cease to be useful in one compound than the 

 most active energies are at work changing it into 

 another. It is only while the glebe is bound 'up in ice 

 that there is a suspension of these energies ; and even 



