« VorigeDoorgaan »
upon the ear, and the drum of the ear of an elephant. [Pl. v. fig 4.} He discovered in it what he calls a radiated muscle, that is, straight muscular fibres, passing along the membrane from the circumference to the centre; from the bony rim which surrounds it towards the handle of the malleus to which the central part is attached. This muscle he supposes to be designed to bring the membrane into unison with different sounds: but then he also discovered, that this muscle itself cannot act, unless the membrane be drawn to a stretch, and kept in a due state of tightness, by what may be called a foreign force, viz. the action of the muscles of the malleus. Our author, supposing his explanation of the use of the parts to be just, is well founded in the reflection which he makes upon it: “that this mode of adapting the ear to different sounds, is one of the most beautiful applications of muscles in the body; the mechanism is so simple, and the variety of effects so great." *
In another volume of the transactions above referred to, and of the same year, two most curious cases are related, of persons who retained the sense of hearing, not in perfect, but in a very considerable degree, notwithstanding he almost total loss of the membrane we have been describing. In one of these cases, the use here assigned to
* As the ear of man and fish has been described, it may not be improper in this place to state, that the other classes of animals are no less admirably provided with an ear, adapted to their peculiar habits and economy.
In amphibious animals the organ of hearing has an intermediate structure; in some species of this class, the ear resembling fish, in others it more resembles the formation of terrestrial animais.
There is an important addition to this organ in birds: viz. a cochlea and proper tympanum.
In quadrupeds we find a more complicated organization; to collect the vibrations of sound, they have an external ear, and all those parts, though of a different figure, which belong to the human ear.
The capacity for enjoyment of music is mental, but all the curious varieties of sound, which are the source of this enjoyment, are communicated by the mechanical provisions of the ear. We are astonished at the varieties of sensation; the ear is capable of perceiving four or five hundred Variations of tone in sound.
“ Hence we may conceive a prodigious variety in the same tone, arising from irregularities of it occasioned by constitution, figure, situation or manner of striking the sonorous body; from the constitution of the elastic medium, or its being disturbed by other motions; and from the constitution of the ear itsell, upon which the impression is made. A Aute, a violin, a hautboy, a French horn, may all sound the same tone, and be easily distinguishable. Nay, if twenty human voices sound the same note, and with equal strength, there will be some difference.” Reid's Enquiry, page 98.–Paxton.
that membrane, of modifying the impressions of sound by change of tension, was attempted to be supplied by strain ing the muscles of the outward ear.
- The external car, we are told, “had acquired a distinct motion upward and backward, which was observable whenever the patient istened to anything which he did not distinctly hear; when he was addressed in a whisper, the ear was seen immediately to move; when the tone of voice was louder, it then remained altogether motionless."
It appears probable, from both these cases, that a collateral, if not principal, use of the membrane, is to cover and protect the barrel of the ear which lies behind it. Both the patients suffered from cold: one, a great increase of deafness from catching cold;" the other, very
considerable pain from exposure to a stream of cold air.” Bad ef'fects therefore followed from this cavity being left open to the external air; yet, had the Author of nature shut it up by any other cover, than what was capable, by its texture, of receiving vibrations from sound, and, by its connexion with the interior parts, of transmitting those vibrations to the brain, the use of the organ, so far as we can judge, must have been entirely obstructed.
OF THE SUCCESSION OF PLANTS AND ANIMALS.
The generation of the animal no more accounts for the contrivance of the eye or ear, upon
the supposition stated in a preceding chapter, the production of a watch by the motion and mechanism of a former watch, would account for the skill and intention evidenced in the watch so produced; than it would account for the disposition of the wheels, the catching of their teeth, the relation of the several parts of the works to one another, and to their common end; for the suitableness of their forms and places to their offices, for their connexion, their operation, and the useful result of that operation. I do insist most strenuously upon the correctness of this comparison; that it holds as to every mode of specific propagation; and that whatever was true of the watch, under the hypothesis above mentioned, is true of plants and animals.
1. To begin with the fructification of plants. Can it be doubted but that the seed contains a particular organiza
tio:? Whether a latent plantule with the means of temporary nutrition, or whatever else it be, it encloses an organization suited to the germination of a new plant. Has the plant which produced the seed anything more to d with that organization, than the watch would have had to do with the structure of the watch which was produced in the course of its mechanical movement? I mean, Has it anything at all.to do with the contrivance? The maker and contriver of one watch, when he inserted within it a mechanism suited to the production of another watch, was, in truth, the maker and contriver of that other watch. All the properties of the new watch were to be referred to his agency: the design manifested in it, to his intention: the art, to him as the artist: the collocation of each part to his placing: the action, effect, and use, to his counsel, intelligence, and workmanship. In producing it by the intervention of a former watch, he was only working by one set of tools instead of another. So it is with the plant and the seed produced by it. Can any distinction be assigned between the two cases; between the producing watch, and the producing plant; both passive, unconscious substances; both, by the organization which was given to them, producing their like, without understanding or design; both, that is, instruments ?
II. From plants we may proceed to oviparous animals; from seeds to eggs. Now, I say, that the bird has the same concern in the formation of the egg which she lays, as the plant has in that of the seed which it drops; and no other, nor greater. The internal constitution of the egg is as much a secret to the hen, as if the hen were inan imate. Her will cannot alter it, or change a single feather of the chick. She can neither foresee nor determine o. which sex her brood shall be, or how many of either; yet the thing produced shall be, from the first, very different in its make, according to the sex which it bears. So far, therefore, from adapting the means, she is not beforehand apprized of the effect. If there be concealed within that smooth shell a provision and a preparation for the production and nourishment of a new animal, they are not of her providing or preparing: if there be contrivance, it is none of hers. Although, therefore, there be the difference of life and perceptivity between the animal and the plant, it is a difference which enters not into the account. It is a foreign circumstance. It is a difference of properties not employed. The animal function and the vegetable func lion are alike destitute of any design which can operate upon
che form of the thing produced. The plant has no design in producing the seed, no comprehension of the nature or use of what it produces; the bird with respect to its egg, is not above the plant with respect to its seed. Neither the one nor the other bears that sort of relation to what proceeds from them, which a joiner does to the chair which he makes. Now a cause, which bears this relation to the effect, is what we want, in order to account for the suitableness of means to an end, the fitness and fitting of one thing to another, and this cause the parent plant or animal does not supply.
It is farther observable concerning the propagation of plants and animals, that the apparatus employed exhibits no resemblance to the thing produced; in this respect holding an analogy with instruments and tools of art. The filaments, antheræ, and stigmata of flowers, bear no more resemblance to the young plant, or even to the seed, which is formed by their intervention, than a chisel or a plane does to a table or chair. What then are the filaments, antheræ, and stigmata of plants, but instruments strictly so called? *
III. We may advance from animals which bring forth eggs, to animals which bring forth their young alive: and of this latter class, from the lowest to the highest; from irrational to rational life, from brutes to the human species;
* Nearly akin to the reproduction of plants and animals by generation, is the reproduction of parts of animal bodies which have been destroyed, and the reparation of those which have been injured. To say nothing of the reproduction of limbs in crustaceous animals, the wonderful but well attested fact, of the formation of a new eye in an animal of the lizard kind, in the place of one which had been cut out of the socket, is one which no atheistical theory can approach, in the way of explanation. In the process by which a new eye is formed, the apparatus, instruments and materials, employed, bear no resemblance to the organ to be formed. The small capillary vessels of the root of the eye, construct a new eye, out of the blood which circulates in them. To use a mode of expression like that of our author-the vessels which thus construct a new eye, bear no more resemb.ance to it, than a chisel or a plane, to a table or a chair; and the blood out of which it is made, no more resemblance to it when made, than the metallic ores when taken out of the mine, to a complete and perfectly constructed watch. In this case, we find a contrivance existing in a whole race of animals, for the accomplishment of a purpose which it is not called upon to accomplish in one instance out of a thousand. If the reader will examine the several atheistical modes of evading the force of the arguments for the existence of God, referred to in the next chapter, as well as in various other parts of this volume, he will find that they signally fail in their application to this case.- Ed.
without perceiving, as we proceed, any alteration whatever in the terms of the comparison. The rational animal does not produce its offspring with more certainty or success than the irrational animal; a man than a quadruped, a quadruped than a bird; nor (for we may follow the gradation through its whole scale) a bird than a plant; nor a plant than a watch, a piece of dead mechanism, would do, upon the supposition which has already so often been repeated. Rationality therefore has nothing to do in the business. If an account must be given of the contrivance which we observe; if it be demanded, whence arose either the contrivance by which the young animal is produced, or the contrivance manifested in the young animal itself, it is not from the reason of the parent that any such account can be drawn. He is the cause of his offspring in the same sense as that in which a gardener is the cause of the tulip which grows upon his parterre, and in no other. We admire the flower; we examine the plant; we perceive the conduciveness of many of its parts to their end and office; we observe a provision for its nourishment, growth, protection, and fecundity; but we never think of the gardener in all this. We attribute nothing of this to his agency; yet it may still be true, that without the gardener wa should not have had the tulip: just so it is with the succession of animals even of the highest order. For the contrivance discovered in the structure of the thing produced, we want a contriver. The parent is not that contriver. His consciousness decides that question. He is in total ignorance why that which is produced took its present form rather than
other. It is for him only to be astonished by the effect. We can no more look therefore to the intelligence of the parent animal for what we are in search of, a cause of relation, and of subserviency of parts to their use, which relation and subserviency we see in the procreated body, than we can refer the internal conformation of an acorn to the intelligence of the oak from which it dropped, or the structure of the watch to the intelligence of the watch which produced it; there being no difference, as far as argument is concerned, between an intelligence which is not exerted, and an intelligence which does not exist.