n. Yet how
much more manifold and definite, the organization of an insect, than that
of the preceding class, the patient researches of Swammerdam and Lyonnet
have evinced, to the delight and admiration of every reflecting mind.

In the insect, for the first time, we find the distinct commencement of a
separation between the exponents of sensibility and those of irritability;
_i.e._ between the _nervous_ and the _muscular_ system. The latter,
however, asserts its pre-eminence throughout. The prodigal provision of
organs for the purposes of respiration, and the marvellous powers which
numerous tribes of insects possess, of accommodating the most corrupted
airs, for a longer or shorter period, to the support of their
excitability, would of itself lead us to presume, that here the _vis
irritabilis_ is the reigning dynasty. There is here no confluence of
nerves into one reservoir, as evidence of the independent existence of
sensibility _as_ sensibility;--and therefore no counterpoise of a vascular
system, as a distinct exponent of the irritable pole. The whole
muscularity of these animals, is the organ of irritability; and the nerves
themselves are probably feeders of the motory power. The petty rills of
sensibility flow into the full expanse of irritability, and there lose
themselves. The nerves appertaining to the senses, on the other hand, are
indistinct, and comparatively unimportant. The multitude of immovable eyes
appear not so much conductors of light, as its ultimate recipient. We are
almost tempted to believe that they constitute, rather than subserve,
their sensorium.

These eye-facets form the sense of light, rather than organs of seeing.
Their almost paradoxical number at least, and the singularity of their
forms, render it probable that they impel the animal by some modification
of its irritability, herein likewise containing a striking analogy to the
known influence of light on plants, than as excitements of sensibility.
The sense that is nearest akin to irritability, and which alone resides in
the muscular system, is that of touch, or feeling. This, therefore, is the
first sense that emerges. Being confined to absolute contact, it occupies
the lowest rank; but for that very reason it is the ground of all the
other senses, which act, according to the ratio of their ascent, at still
increasing distances, and become more and more ideal, from the tentacles
of the polypus, to the human eye; which latter might be de