6 ON THE LATERAL ACCRETION OF THE STEMS OF SHRUBS, &c. 
being colourless 3 but by careful dissection and optical assistance, they 
may be detected ; and their identity only disappears when the strongest 
magnifying microscopes fail. We can detect the plumula and radicle 
in the smallest seed; we can observe the incipient shoot, with its leaves 
and flowers, depressed into the small compass of a bud, whence they 
are developed in time; but their identity is as certain and appreciable 
while in the seed or bud, as they are after they are elongated to three 
or four feet in length. 
If, then, every exterior part of the plant has rudimental existence 
before expansion, why should we not conclude that the internal annual 
accretion of the alburnum has a similar origin ? 
The only argument which can be brought against this hypothesis is, 
the inconspicuousness of the incipient alburnum during winter. Then, 
indeed, its identity is rather to be conceived than perceived, being only 
a thin coating of glairy matter, covering the outer side of the former 
summer’s alburnum, and within the liber. But as there are many 
other vegetable productions which are equally inconspicuous in winter, 
and yet arrive at considerable bulk in summer, this argument has no 
force. That it exists, and is quickly active in early spring, is obvious 
from the success of grafting at that season. It is this that forms the 
living cement which unites the graft with the stock, and in summer 
is that plastic membrane which receives the inserted bud in its 
embrace. 
Taking all these circumstances into consideration, we can come to 
no other conclusion, than that the alburnum is generated from a pre¬ 
existing membrane, and cannot be formed from any accumulation or 
mutability of the sap. That the sap is compounded of different 
qualities incident to the plant; that it is transfusible throughout the 
system ; that it fills, distends, and, in many cases, consolidates the 
ligneous frame, are all self-evident facts, which need not be further 
insisted on. - 
It only remains to add, that we earnestly recommend this subject to 
the consideration of our readers ; and should any of them see cause for 
objection to any part of the above statement, we shall feel obliged by 
any remarks they may be pleased to hand to us. And should our 
observations meet the eye of Mr. Hoare, whose name we have made 
free with, and he have any corrections to present, we should feel 
extremely happy to attend to anything falling from that gentleman’s 
pen. —Ed. 
