72 PATTERSON v. M'CAUSLAND.—3 BLAND.

transverse section of it, is, however, a kind of evidence which can
only be obtained by a posthumous examination. Such examina-
tion of the bodies of animals are common, and have often been
found very instructive in relation to the purposes for which they
have been made; but it is believed such an examination never was
made with a view to ascertain the age of the animal, or when it
would attain such a maturity as would give the greatest value and
utility to its body, or that of similar animals. Post mortem exam-
inations of the bodies of animals are often made with a view to
ascertain points of comparative anatomy; to observe the organiza-
tion of the body, so as thereby the better to understand how living
creatures of the same species should be treated in health or in dis-
ease; or to ascertain what may have been the immediate
88 * cause of its death. So, too, the post mortem examination
of a tree can be of no value for any other purpose; except it be to
find a rule for ascertaining its age, and thereby the ages of living
trees of the same species; or to find a rule for determining the rate
per annum at which they may be expected to continue their en-
largement until they reach the ultimate term of their lives.

But assuming it to be true, that the number of the concentrical
rings observed in the trunk of a tree, do always exactly correspond
with the number of years of its age, then at least one important
step would seem to have been made by such post mortem examina
tions towards ascertaining the ages of trees in general; as, for ex-
ample, if by the felling of an oak of thirty-four inches in diameter,
it should be found to have two hundred concentric layers; and,
consequently, to be two hundred years old; and so to have in-
creased in diameter at the rate of one-twelfth part of an inch annu-
ally; and then, assuming it to be true, that all the immediately ad
jacent and similarly situated oaks had increased in diameter at
the same average annual rate; it follows, that the age of every
living oak in a similar soil and exposure, might from the measure-
ment of its circumference, be exactly ascertained by a post mortem
examination of any one, and so of every other species of trees.
Let us follow out this hypothesis, and see to what it will lead.

It has been found, that a larch tree, in England, will, under
favorable circumstances, increase, until fifty years of age, at the
rate of half an inch annually in diameter; and that some elms,
planted in France in the year 1580, if what is said of their circum-
ference be correct, had increased at the same rate in diameter
until two hundred and forty years of age. 2 Mitch. Am. Sylra.
225. (f) But it has been observed that the latter concentrical

(f) "Several elm trees, said to have been planted in the public green at
New Haven, in Connecticut, in the year 1688, were standing in the year
1838, and then measured about fourteen feet in circumference; which gives
an increase of diameter at the rate of about the half of an inch annually."
The Globe newspaper, published at Washington, 21st September, 1838.