REVIEW. 
79 
“ Every developed member of a tree is imbued with the vital prin¬ 
ciple in its early existence, and retains it while in the act of expan¬ 
sion, but no longer. The bark is an exterior and the wood an interior 
increment ; both have been inflated into form, and forced into position 
by the life; but as soon as the form is complete, and the position 
imposed, they are deserted by it, and when they cease to partake of 
its influence entirely, they succumb to decay.” 
“ There are, therefore, two states or degrees of vegetable life. The 
first is always present in those members which are capable of ampli¬ 
fication, or are in the act of accretion, i., e., expanding from a small 
to a large volume. The second is that state in which it is only con¬ 
servative, but without the power of a further growth of the members 
preserved by it. The first it is deemed proper to designate by the 
name of vital envelope, whence proceeds every new member of trees, 
shrubs, and many herbaceous plants. The second is, that state of 
the bark and alburnum which, haying but recently come into full 
form and magnitude, serve as conductors of the fluids of the system 
for a certain time, but from which the actual life has for ever fled.” 
“Where then does the living principle reside ? In the pith P No; 
in the wood, or in the bark P No, in neither of these, but it is always 
found at all times between the liber and the alburnum, slightly at¬ 
tached to both, but united to neither; it is reasonable, therefore, to 
conclude, that it is a distinct member of the system.” 
This slender body of vitality, or vital envelope, is constitutionally 
compound, not simple, as such a thin tissue may be supposed to be; 
containing the rudiments of both roots and buds; and moreover is 
the source of all accretion, whether as to magnitude or number of 
the parts produced. 
“The foregoing idea of the existence of a distinct vital member, 
whence all new accretions proceed, is directly opposed to the modern 
doctrine of the “ organisable property” of the elaborated sap of plants. 
The idea is founded upon the general law of vegetable nature; for 
where do we find the most insignificant vegetable body come into 
visible existence without having a pre-existing embryo or rudimental 
atom, whence it derives its essential structure and qualities. There 
is no such instance in nature. Can the most minute species of 
Fungi spring forth without its propago or the smallest herb without 
a seed, or previously existing part of itself? Is the bark or wood 
self-productive ? No: when either is destroyed it cannot be re¬ 
newed but bv the assistance of that vital member which is the orison 
*/ / O 
of both.” 
Admitting, then, that plants and certain parts of plants possess 
