OA PRINCIPLES OF BOTANY, ETC. 
of electricity, on the contrary, according to recent 
experiments, proves beneficial both to animals and 
vegetables. 
Th re sole and characteristic mark of vital power, 
as Mr Humboldt justly observes in his Aphorisms, 
we find in the combination of the constituent parts, 
which in the living body are always combined 
against the laws of ihe emical affinity; but as soon 
as life ceases, nature restores the balance of affinity 
by fermentation, which we clearly observe in dead 
animals and their organs, as well as in vegetables. 
Bodies, therefore, in retaining life, follow the laws 
of vital power; when destitute of it, those ef che- 
mica! affimity. 
‘The formative nisus is particularly well observed 
in the animal kingdom, especially in the Vermes. 
But even plants possess it, if we regard their pe- 
culiar structure, though they are totally incapable of 
reproducing different parts. No leaf whatever, once 
urt and purposely mutilated when new, ever re- 
roms 
a 
gains its former shape by the formative nisus. In 
some plants which have many filaments, it 1s alleged 
that after these has been cut off, something like 
laments has been reproduced ; though I don’t ven- 
ture to consider this as a certain fact. But even 
this could by mo means prove a complete repro 
duction, as the filaments had no perfect anthers. We 
commonly consider it as a reproducing power, when 
4 willow-or other fast crowing tree or shrub, after 
having Leen clipped, again shoots forth numberless 
new branches. But neither the willow nor other trees 
nor shrubs or undershrubs are simple plants, but 
compound 
