Observations on the nature, longevity and size of trees / by Alexander Harvey.

  • Harvey, Alexander, 1811-1889.
Date:
[1847]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the nature, longevity and size of trees / by Alexander Harvey. Source: Wellcome Collection.

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    such, the cessation of its vital actions, and the loss of its vital properties, is a fundamental law of the constitution of every living being. The provisions to which it owes its existence, and by which its vital actions are for a time performed, neces¬ sarily involve the extinction of its vital powers. Such changes are gradually wrought in it by the very agency of its vitality as are ultimately incompatible with, the longer continuance of life, and death follows as a matter of course. And those changes are attended by, if they do not essentially consist in, a gradually increasing languor or sluggishness in the activity of the vital processes, and by a corresponding density and rigidity of the textures composing the organism—constituting a state to which the name of old age is given, which obtains uniformly when life is not prematurely cut short, and is in¬ dicative of the approach of death. Again, all organized beings have a definite size or bulk of organism. Of lifeless inorganic bodies, it cannot be affirmed that they possess any such quality, being smaller or larger to any conceivable extent, according as circumstances may determine. It is otherwise, however, with animal and vegetable organisms, which have naturally a fixed or standard size to which they grow, and from which they never greatly deviate. This fact in their history may not perhaps be so obviously true as that of a limited duration of life; nevertheless it can be shewn to be an equally general one, and the exceptions to it to be only apparent, not real. But, acquiescing in the truth and universality of the prin¬ ciple now referred to, it may be confidently asserted in regard to trees, that, on the assumption stated as to their nature— to wit, that every individual tree is an individual plant—there are many facts in their history which it is difficult to recon¬ cile with that principle ; and, generally, that nothing definite or satisfactory has yet been ascertained respecting either the natural longevity or the natural size of any one species of tree,—a circumstance which contrasts remarkably with the precision of our knowledge, so far as it goes, as to these particulars in the case of animals, and the more, from the facilities that exist for making observations upon trees.