82 
REVIEW. 
This hypothesis is only objectionable, perhaps, on the ground of 
the difhculty of conceiving how such.a mass of organization, forming 
the extended trunk of a full grown tree, can be contained in such a 
slender space as that between the liber and the wood of one of four 
year’s growth. But this difficulty is not greater, indeed not quite 
so incomprehensible, as is the other supposition already alluded to, 
namely, that all increments are elaborated from juices and qualities 
inherent in ihe plant; or formed by accidental associations of cer¬ 
tain electro-chemical bodies extractable from the earth, air, and water. 
The identity of the vital envelope, during summer, is visible and pal¬ 
pable ; and if in winter it he only a cincture of transparent cellular 
matter, no doubt need be entertained of its subsequent expansibility. 
That vegetable matter appears in the first stage of its existence as a 
colourless homogenous mass is indisputable ; and that it gradually 
gains consistency and organic form, may be easily believed, by ex¬ 
amining an orange when first visible in the flower, and again when 
fully ripe and deprived of its juice. Besides, the accrescent powers, 
and indefinite limits of vegetation in this case, should banish incre¬ 
dulity ; in many other instances it is equally surprising; witness the 
monstrous gourd, the majestic oak, the magnificent Banyan Fig; the 
latter shading acres of surface, all originating in an atom of a seed. 
The new laver of wood, which is added on the old stem or trunk, 
ranges with the first layer of wood on the terminal shoots. On the 
latter all primary buds, and consequently branches, originate. The 
shoots developed this year, except water shoots,* are based on the 
alburnum formed on the last, and the buds formed in this year are 
seated on this year’s alburnum, and on which they remain to be de¬ 
veloped in the next or some following year. The pith, wood, buds, 
and bark of every shoot are all simultaneously produced. 
But all buds and branches are not primary. Such as are produ¬ 
ced from an old stem, ( b , Fig. 12) whether naturally or by conse¬ 
quence of pruning, may be called, for the sake of distinction, second¬ 
ary. f These can have no immediate connection with the first 
formed layer of wood and pith and therefore invariably spring from 
the envelope. 
* Water shoots are such as are produced on luxuriant growing- shoots of the 
present year, frequently seen on the peach, apricot, and always on the grape vine. 
f Botanists suppose that there are what they call “ adventitious buds,” that 
is, if buds come forth from other places than the axils of the leaves or bractea, 
they are adventitious and new creations. Their appearance, indeed, may be ad¬ 
ventitious, but not their identity. If a bud can be produced without a rudiment, 
so may a whole plant. 
