426 
ON INSTINCT. 
which the Deity acts upon animal organization and structure, 
to produce all the varied instincts*.’* 
I confess that I have not sufficiently studied this part of the 
subject to give a decided opinion on it; yet, from what I have 
observed, I consider that these are strong grounds for the belief. 
We have some remarkable circumstances connected with the 
vegetable kingdom that support the opinion. I have shewn 
in the course of the lecture, that some of the most wonderful 
instincts of animals are those connected with the preservation 
and propagation of the species: so, in plants, this is beautifully 
shewn in the development of those parts peculiarly connected 
with the production of the seed—the expanded flower, and the 
operations going on in it, is the analogue of the reproductive 
instinct of the animal: this is all produced hy physical action 
upon the organization of the plant. Now, if you consider the 
infinite variety of plants, and the wonderful diversity of their 
parts of fructification, and that they are all produced in their seve¬ 
ral seasons and stations by the action of some physical powers 
upon their varied organization, and by means of the soil in which 
they are planted, we shall think it nearly as wonderful and unac¬ 
countable as the instinctive operations of the various creatures 
that feed upon, them; and as all plants have their appropriate 
fructification, so they have other peculiarities connected with 
their situation, nutriment, and mode of life, corresponding, in 
some measure, with those instincts that belong to other parts of 
an animal economy. Some with a climbing or voluble stem, con¬ 
stantly turning one way, and some as constantly turning another. 
Thus the hop twines from the left to the right, while the hind- 
weed climbs from the right to the left. Some close their leaves 
in the night, and seem to go to sleep; others shew a remarkable 
degree of irritability when touched. The blossoms of many 
flowers, as the sun-flower, follow the sun from his rising to his 
setting. These, and many other examples, could be produced, 
shewing that the same physical action upon a peculiar organi¬ 
zation produces all these effects. All these circumstances indi¬ 
cate an analogy between certain phenomena observable in the 
history of plants and some of the instincts of animals; and tend 
to prove that the proximate cause of both may be very nearly 
related, and that, as the immediate cause of the vegetable instinct 
is clearly physical, so may be that of the animal. But all this 
reasoning is mere conjecture. In truth, every attempt that 
has been made to discover the cause of instinct has been utterly 
vain and unsatisfactory. 
As to the doctrine, that instinct is the result of the immediate 
* Kirby's Bridgewater Treatise. 
