« VorigeDoorgaan »
the organ for its reception and retention: we have, thirdly, the excretory duct, annexed to that organ: and we have, lastly, the determination of the milk to the breast, at the particular juncture when it is about to be wanted. We have all these properties in the subject before us: and they are all indications of design. The last circumstance is the strongest of any. If I had been to guess beforehand, I should have conjectured, that at the time when there was an extraordinary demand for nourishment in one part of the system there would be the least likelihood of a redundancy to supply another part. The advanced pregnancy of the female has no intelligible tendency to fill the breasts with milk. The lacteal system is a constant wonder: and it adds to other causes of our admiration, that the number of the teats or paps in each species is found to bear a proportion to the number of the young. In the sow, the bitch, the rabbit, the cat, the rat, which have numerous litters, the paps are numerous, and are disposed along the whole length of the belly ; in the cow and mare, they are few. The most simple account of this, is to refer it to a designing Creator.
But in the argument before us, we are entitled to consider not only animal bodies when framed, but the circumstances under which they are framed: and in this view of the subject, the constitution of many of their parts is most strictly prospective,
III. The eye is of no use, at the time when it is formed. It is an optical instrument made in a dungeon; constructed for the refraction of light to a focus, and perfect for its purpose, before a ray of light has
had access to it; geometrically adapted to the properties and action of an element, with which it has no communication. It is about indeed to enter into that communication: and this is precisely the thing which evidences intention. It is providing for the future in the closest sense which can be given to these terms: for it is providing for a future change; not for the then-subsisting condition of the animal; not for any gradual progress or advance in that same condition; but for a new state, the consequence of a great and sudden alteration, which the animal is to undergo at its birth. Is it to be believed that the eye was formed, or, which is the same thing, that the series of causes was fixed by which the eye is formed, without a view to this change; without a prospect of that condition, in which its fabric, of no use at present, is about to be of the greatest; without a consideration of the qualities of that element, hitherto entirely excluded, but with which it was hereafter to hold so intimate a relation? A young man makes a pair of spectacles for himself against he grows old; for which spectacles he has no want or use whatever at the time he makes them. Could this be. done without knowing and considering the defect of vision to which advanced age is subject? Would not the precise suitableness of the instrument to its purpose, of the remedy to the defect, of the convex lens to the flattened eye, establish the certainty of the conclusion, that the case, afterwards to arise, had been considered beforehand, speculated upon, provided for all which are exclusively the acts of a reasoning mind. The eye formed in one state, for use only in another state, and in different state, affords a proof no less clear of des. tination to a future purpose; and a proof proportionably stronger, as the machinery is more complicated, and the adaptation more exact.
IV. What has been said of the eye, holds equally true of the lungs. Composed of air-vessels, where there is no air; elaborately constructed for the alternate admission and expulsion of an elastic fluid, where no such fiuid exists; this great organ, with the whole apparatus belonging to it, lies collapsed in the fætal thorax; yet in order, and in readiness for action, the first moment that the occasion requires its service. This is having a machine locked up in store for future use; which incontestably proves, that the case was expected to occur, in which this use might be experienced: but expectation is the proper act of intelligence. Considering the state in which an animal exists before its birth, I should look for nothing less in its body than a system of lungs. It is like finding a pair of bellows in the bottom of the sea ; of no sort of use in the situa. tion in which they are found; formed for an action which was impossible to be exerted; holding no relation or fitness to the element which surrounds them, but both to another element in another place.
As part and parcel of the same plan, ought to be mentioned, in speaking of the lungs, the provisionary contrivances of the foramen ovale and ductus arteriosus. In the fætus, pipes are laid for the passage of the blood through the lungs; but, until the lungs be inflated by the inspiration of air, that passage is impervious, or in a great degree obstructed. What then is to be done? What would an artist, what would a master, do upon the occasion ? He would endeavour, most probably, to provide a temporary passage, which might carry on the communication required, until the other was open. Now this is the thing which is actually done in the the heart :-Instead of the circuitous route through the lungs, which the blood afterwards takes, before it get from one auricle of the heart to the other; a portion of
the blood passes immediately from the right auricle to the left, through a hole, placed in the partition, which separates these cavities. This hole, anatomists call the foramen ovale.
There is likewise another cross cut, 'nswering the same purpose, by what is called the ductus arteriosus, lying between the pulmonary artery and the aörta. But both expedients are so strictly temporary, that, after birth, the one passage is closed, and the tube which forms the other shrivelled
into a ligament. If this be not contrivance, what is ?
But, forasmuch as the action of the air upon the blood in the lungs appears to be necessary to the perfect concoction of that fluid, i. e. to the life and health of the animal (otherwise the shortest route might still be the best), how comes it to pass that the fætus lives, and grows, and thrives, without it? The answer is, that the blood of the fætus is the mother's; that it has undergone that action in her habit; that one pair of lungs serves for both. When the animals are separated, a new necessity arises; and to meet this necessity as soon as it occurs, an organisation is prepared. It is ready for its purpose; it only waits for the atmosphere; it begins to play, the moment the air is admitted to it.
WHEN several different parts contribute to one effect; or,
which is the same thing, when an effect is produced by the joint action of different instruments; the fitness of such parts or instruments to one another, for the purpose of producing, by their united action, the effect, is what I call relation: and wherever this is observed in the works of nature or of man, it appears to me to carry along with it decisive evidence of understanding, intention, art. In examining, for instance, the several parts of a watch, the spring, the barrel, the chain, the fusee, the balance, the wheels of various sizes, forms, and positions, what is it which would take an observer's attention, as most plainly evincing a construction, directed by thought, deliberation, and contrivance? It is the suitableness of these parts to one another; first in the succession and order in which they act; and, sea condly, with a view to the effect finally produced. Thus, referring the spring to the wheels, our observer sees in it, that which originates and upholds their motion; in the chain, that which transmits the motion to the fusee ; in the fusee, that which communicates it to the wheels; in the conical figure of the fusee, if he refer to the spring, he sees that which corrects the inequality of its force. Referring the wheels to one another, he notices, first, their teeth, which would have been without usc or meaning, if there had been only one wheel, or if the wheels had had no connexion between themselves, or common bearing upon some joint effect; sesondly, the correspondency of their position, so that the teeth of one wheel catch into the teeth of another;