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Sight is a species of touch: the rays- that com* from an object falling on the eye affect the retina; the motions they occasion there are communicated to the optic nerve, and produce the sense of seeing. Although many insects are endowed with this sense it is not common to them all. Some of those which enjoy it, have it in greater persection than man. Their sight is so quick, that it comprehends, if we may so speak,even an atom. We cannot view objects behind us, without turning round our head'; but there are many insects which, without such motion, can fee al! the objects Which surround them. Men m general cannot lee in the dark, but many insects see better in the night than in the day.
God has not bestowed the sense of hearing on all insects; and I know none that have ears; we cannot however doubt, that there are many which are endowed with this sense. As the lovers of music assemble at the sound of the instruments they like, we see many insects collecting together at certain sounds they are pleased with. A disagreable noise disturbs and frightens others. This is more surprising if, as I have said thev have no ears to serve as the organ of hearing. When a noise is made, a tremulous motion is communicated to the air, which striking on the tympanum of our ears, is by the animal spirits conveyed to the brain, and produces in us the sense of hearing: this is simple, and can be easily conceived. But how can this happen without ears?
Insects have nothing like a nose, but we cannot fof that reason deny that they possess the sense of smelling. We observe that they often distinguish smells; and that they are sensible os the perfume that exhales from odorous substances. Their inclinations in this respect differ very much; some give the preserence to those smells which we think agreeable, others are aftti cte J by the odour of substances which they greesfily seek after, while others more delicate avoid them and fly from them with the greatest; aversion. The sense of hearing in insects is more acute than in man of which I know two instances. The first is, that they discover their food by this fense, and can distinguish by it the qualities of vegetables ; the second is that they can smell the food that is agreeable to them at a much greater distance than man can. But we are more than recompenced for our inferiority in this respect to insects: the reason we are endowed with, enables us to dispense with such exquisite delicacy of smell, and is preferable to any advantages which insects have over us.
Taste is a .motion of the animal spirits excited by particles acting on the nerves of the tongue which communicate that motion to the brain, and thus af_ sect the foul. Insects have no tongue like other animak, but their trunk and their palpi, of which we fhail speak in the sequel, serve them instead of it and are the organs of their taste. This fense is of great use to them; by it they distinguish between food that is salutary, and food that would be noxious to them. What 1 have remarked, in some of the former Chapters with regard to the food of infects, mews clearly, that the fense of taste in these creatures is very various. What some love, is abominated by others; some live on fluids, others on solids; some live on the green blade, others on the dried grain. Some delight only, in the juice of flowers; others fuck the blood of animals. To these last, every species of blood is not equally agreeable; some preferring that of man, others that of quadrupeds, no do they attack every quadruped indifferently. Lastly there are injects which devour animai lubstances, some when it is fresh, others not till it becomes putrid.
Infects though destitute of the organs of some of
the the fenses are not however deprived of the feelings! they occasion. Hitherto the ears have hot been discovered in any insects; the greater part have nevertheless the fense of hearing in a very eminent degree; they have no nose, and yet their sense os smell is exceedingly delicate. What greater instance can be desired of the infinite wisdom of the Creator, which is not confined to a single mode of producing the effect? If rhe greater part of animals have ears, as the organ of hearing, and a nose, as that of smell, this is not a proof that the ears and the nose are absolutely necessary to produce these sensations. God can when he pleases form creatures capable of experiencing the fame sensations by means of other organs* Should it be objected that insects, which are sensible to smells and to sounds, must have a nose and ears, but that the structure of them is so fine and so delicate that we cannot discern them even with the assistance of a good microscope, the wisdom of the Deity would not on that account be less the subject of admiration Would we not have reason to be astonished at the extent of the power and wisdom of a being who has given sensations to organs so minute as to have hitherto escaped the most diligent scrutiny of the curious? How delicate must be the nerves which tremble at the smallest impressions made by external objects f How subtile must be the animal spirits, which can produce in the soul of these creatures, those motions which lead them to provide for their preservation.
The use which insects make of their fenses corresponds exactly to the views which the wife author ot nature from whom they derive them, proposed when he formed them. Far from employing them in procuring to themselves extravagant pleasures or excesses of any kind, they never use them but to answer their necessities, or as the means of their preferva-> tion. How great is the difference in this respect bev
tween tween them and man! who allows himself to be led astray by voluptuousness, and by all the pleasures pf the fenses, as if the faculty of reason had not been bestowed on him, and as if he had not the power to resist his inclinations. Let us learn from these despised animals to mortify our passions, to indulge in no excesses, and to confine our senses to those uses for which they were given us. How disgraceful is > it for a rational being to confess himself in this respect inferior to (he brutes! Let us fly from luxury, Jet us shun pride, and the vanities of life, and let us employ all our senses in contemplating the works of God, as well those of nature as those of grace. Let our ears be shut against whatever is wicked or indecent, and open only to the important found of the word of God. Let us not abase the organ of our taste by excess in eating, or drinking, but let us use it for our preservation, by living soberly and frugally. It is our duty to take care of our bodily frame; but it is a crime to idolize it, to attend only to its pleasures, and to satisfy all its inordinate appetites.
Man enjoys five fenses, while insects want sometimes one sometimes another. The Deity has also bestowed on him a rational foul which indemnifies him for the superiority that insects have over him with regard to the sensibility of their organs. What thanks ought we not to render him for gifts so valuable! To form a just estimate of the importance of those gifts, let us suppose for a moment that we have lost the use of one or more of'our senses ; we fliall then be convinced how indifpensible they are to our pleasures and convenience. Blind, deaf, without feeling, without taste or smell, what would become of us! Our body would be nothing but a lump of clay, and pur foul incapable of providing for its security and preservation. Let us then praise and exalt the author
Our of so many blessings; let us testify on all occasions the gratitude our hearts are silled with, for his having brought us into existence, and for the gifts of reason and the fenses which make that existence delightful.
Of The Members Of Insects.
For the fake of order I shall divide this Chapter into two Sections. In the first, I shall discourse of the external parts of infects; in the second I shall treat of their internal sttucture. As the former are more easily distinguished than the other I shall be more diffuse upon that subject, and begin with it.
Of the external members of Infers.
As all insects have a skin I shall begin what I propose to say ot the parts of insects, by a description of this member.
The skin is the most external integument which nature has given them: it covers their whole body, connects the different parts and retains them in the places to which they are assigned. It is not of the fame quality in every insect. Those whose manner of life, does not expose them to compression, or to violent