12 Dr Harvey's Observatiotis on (he 



age immediately succeeding that catastrophe 1 Assuming 

 that none such exist, it is, I apprehend, a sufficient answer 

 to that question, to say, that no tree then existing has been 

 able to withstand the " manifold changes and chances" of 

 time. All dead organic matter is subject to, and sooner or 

 later undergoes, chemical change and disintegration ; and by 

 reason thereof the heart-wood of every tree disappears after 

 a time, leaving the trunk hollow within, often reducing it to 

 a mere shell, and thus necessarily weakening the mechanical 

 support given by it to the superincumbent mass. Again, 

 after a tree has stood for many years, the vast height and 

 breadth of surface presented to the wind will enable this to 

 act on it to its destruction at an advantage infinitely greater 

 than in its earlier years. And it is obvious to remark, that 

 the older a tree becomes, its liability to be uprooted by any 

 passing storm of wind increases in a double ratio ; on the one 

 hand, from its greater size, and on the other, from the more 

 extensive decay and removal of the heart-wood. Add to 

 these, the exhaustion of nourishment in the soil, which may, 

 and often does occur, and the inevitable occurrence, in the 

 course of ages, of a thousand other destructive influences — 

 of frost, fire, lightning, hurricanes, the necessities and the 

 caprices of man himself, — and a calculation of chances puts 

 it beyond all doubt, that every tree, or almost every tree, 

 then existing, must long ere now have disappeared from off 

 the face of the earth. 



It remains to substantiate the allegations that have been 

 made in regard to the nature of trees. If these can be esta- 

 blished, the inferences as to their natural longevity, and their 

 natural size, must necessarily be true. 



Now, the evidence to be adduced will consist in shewing, 

 first, That the annual growths proceeding from the buds con- 

 stitute, severally, perfect and independent plants ; and that a 

 succession of such plants may be kept up from year to year, 

 for an indefinite period, from buds alone ; and, secondly, That 

 at the end of the year,' the annual plants or growths in ques- 

 tion, with the exception, of course, of the newly formed buds. 



