^ On Pruning Forest Trees. 393 
It now only remains to present tlie reader with one more extract, 
irom the able work which has famished those already laid before him ; 
I shall then endeavour to elucidate the striking facts recorded, by a 
cursory view of the structure of the vegetable organs, and of the 
agency of electric chemistiy in the laboration of the juices, and the 
final developement of buds and branches. 
A fourth correspondent, has favoured Mr. Withers with a very con- 
clusive set of ol)servations, on the effects of pruning the Black Italian 
Poplar; and he adds, "These observations have confirmed me in the 
opinion, that after the vessels of a tree are filled witli sap from the 
roots in spring, everi/ bud at the time that it shoots externally, sends 
forth innumerable fibres doivnward, between the bark and the wood,* 
constituting, as it were, a number of independent plants, deriving 
their nourishment fi'om the juices deposited there, (which may be com- 
pared to the chyle of the animal body) in the same manner as the 
whole tree derives its grosser nutriment from the earth ; and that it is 
this constant accession offibrotis matter, which causes the increase of 
trees in bulky 
In order to ascertain the causes of the injury that trees receive 
from the loppings and prunings of their branches, it will be needful to 
direct the reader's attention, in the first place, to the origin and pro- 
gress of the buds or germs. Each bud may be considered as an entire 
system in itself, capable of becoming, under favourable circumstances, 
a complete plant or tree ; it is separate, or independent of the parent, 
in as much as respects its indindual constitution, but connected with, 
and dependent on that parent, as to its source, and medium of nutri- 
tion. 1 shall not here pretend to decide between the conflicting 
opinions of philosophers, as to the oiigin of buds. Du Hamel, con- 
cluded, that they existed in a pre-organised state, and were originally 
formed from the pith, because, '* having taken the trunk of a Lime 
tree, of about four or five inches in diameter, about the middle of 
which there was a bud ; and having examined the section with great 
care, he thought he could trace a ray, of a whiter shade than the rest 
of the wood, extending from the pith to the bud." 
The author of a ti'eatise on "Vegetable Phy.siology," published in 
the "Library of Useful Knowledge," contends, that "every germ is 
a distinct insulated individual, the lateral progeny of the plant, gene- 
rated at the period of the developement of the stem, or the branch on 
which it appears as a bud; ' that "all branches proceed from germs 
formed in the earliest unfolding of the parts in which they appear., 
although the buds produced fi'om these germs may not be proti'uded 
until the tree be -greatly advanced in age." This writer also has 
* Dr. Aikin, in his " Kalcndar of Nature," advaixes a siuiilar opinion. 
Voi„ I, No. 9. 3 C 
