VITAL PRINCIPLE. 15 
parts of the organized body, but with external objects, and 
gives warning of the approach and retreat of salutary or 
noxious particles. All its movements, however, are of a 
passive nature. But the power which is now to be consi- 
dered, though nearly related to irritability, is more varied 
in its movements, as it excites us to act upon external ob- 
jects. It is active, not passive. 
As organized bodies, when they begin to enjoy an inde- 
pendent existence, require food for their support, we might 
conceive it possible for a young plant or animal, by means 
of the irritability of the vessels, and those determinate powers 
which have been enumerated, to arrive at maturity, in the ab- 
sence of counteracting agents, were the different substances 
necessary for their nourishment, always placed in contact 
with the vessels fitted for their reception. But the supply of 
nourishment, even where most abundant, is situated at some 
distance. Besides, during the whole term of life, obstacles 
and dangers interrupt and destroy the exercise of the various 
functions. From the form, size and vigour of the living 
bodies which we see around us, we may therefore infer the 
existence of a power which regulates the movements which 
are necessary to obtain a supply of food, to remove or 
counteract opposing obstacles, and to fly from impending 
danger, or repair the injuries which it may occasion. ‘This 
active agent, which appears to be an inseparable com- 
panion of organized existence, we venture to denominate 
Instinct, and shall now endeavour to point out a few in- 
stances of its operations. 
A. Regulates the Supply of Food.—When the seed of 2 
plant is deposited in the soil, under circumstances favour- 
able to its germination, the corcle expands, and, from the 
nourishment furnished by the cotyledon, evolves the ra- 
dicle and the stem. The former of these descends into 
the earth, not according to the laws of gravitation, for it 
