370 
POPULAR SCIENCE REVIEW. 
precisely the same in anatomical construction and governed by 
the same laws. 
The tree from which this twig was cut was one of the oldest 
in the forest, and must have been growing for several centuries ; 
the twig itself had only been growing for thirteen years, yet a 
transverse section of the primary axis of the twig, if compared 
with a cross-section of the stem of the tree, would show, not- 
withstanding their difference in size, the same parts, the pith 
in the centre, a number of concentrical rings of wood, and the 
bark on the outside. But in the twig, there would be only 
thirteen rings of wood, in the stem of the tree several hundreds. 
For each tree, each twig carries in its interior the monumental 
history of its life, and exhibits in the cylindrical woody deposits 
of each vegetative season marks which are ineffaceable excepting 
from the influences of decay. 
Between the years 1850 and 1859, or for the first nine years, 
the growth of the central axis was nineteen inches and four 
lines ; also, in 1851, the primary axis, which was then without 
a single shoot, only produced itself five leaves; but, in 1859, 
it had put forth eleven shoots, all of which were in foliage, 
making the entire leaf crop thirty-eight, or an addition of thirty- 
three leaves to the annual produce in eight years. But the 
growth of the primary axis, between 1859 and 1863, was only 
two inches and seven lines, with an addition to the annnal 
leaf-crop of only six leaves, and this, too, in four years. Our 
twig was, therefore, cut when it was approaching the limit of its 
vegetative progress, for its growth annually was stagnating, as 
is evident from the approximation of the sets of annuli at its 
extremities, and the slower increase in the annual extension of 
its leaf surface. 
An animal may continue to live after it ceases to grow, but 
it is not so with a tree or a twig. For a tree or a twig con- 
tinues to grow as long as it lives, and when it ceases to grow it 
ceases to live. This gradual and continuous stagnation of 
growth at the extremities of our twig is, therefore, also indica- 
tive of the fact, that its vegetative force was gradually expiring, 
and also shows that its hfe was rapidly drawing to its close. 
Once more, we have seen that fifty-four leaves were employed 
in constructing the primary axis, yet only fifteen of them pro- 
duced buds which became branches ; also, that these fifteen 
branches, although constructed by 299 leaves, developed only 
fourteen shoots ; for, referring to the plate, the reader will find 
that the first side branch produced three ; the second, nine ; 
and the seventh, two shoots ; it follows that of these 299 leaves 
only fourteen produced vitally active buds, and that the axilla of 
all the others remained unfruitful. Therefore, the total number 
of abortive or rudimentary buds in the entire twig must be 353 
-(15 + 14) = 324. 
