must pass through it. The crystalline lens has a refractive power greater than that of water, and less than that of glass. Chenevix shewed that the chief cause of the difference between the refractive powers of this and the other humours of the eye is the presence of different proportions of albumen.

Anterior to the crystalline lens is placed the aqueous humour; a fluid in no respect distinguishable from water, save that it holds in solution several saline ingredients. In this fluid the iris, the dark part of the eye which surrounds the pupil, floats like a curtain, dividing it into two chambers-the anterior, or that which is situated between the iris and the cornea, and the posterior, or that which is situated between the iris and the crystalline lens. There is reason to believe that the iris consists of two sets of muscular fibres, one set being circular, the other radial; and it is conjectured that their function is to contract and expand the aperture of the pupil. Which of these conditions is the state of repose of the iris, is not certain. Fontana thought that when the pupil is contracted, and the iris consequently expanded, the latter is in a state of relaxation, this being the case in sleep. If the iris is muscular, its fibres are not of the same kind as those which compose the muscles. The pupil in man and most animals is perfectly round; but in animals which climb, it is elliptical, the ellipse being perpendicular to the body: in the frog it forms a rhomboid placed transversely, and in the crocodile it is a vertical fissure.

The optic nerve is the only part of the eye that is sensible to light, all the other parts being simply the media by which the light is conveyed to it. It enters the eye from behind, and expands in a circular direction over the back part of the organ, being situated behind all the humours, so as to receive and concentrate all the rays of light. In its expanded form the optic nerve is called the retina.

In consequence of the outer coat of the eye, called sclerotic (from σkλnpós [skleros], hard, on account of its firm texture), being thick, and incapable of transmitting light, the eye would be dark, were it not for the transparency of the cornea (so named from its horny consistence), which is a continuation of the sclerotic, and situated immediately before the pupil. The cornea, being perfectly transparent, serves the purpose of a window: and it would, from its appearance, seem to be less highly organised than the other parts of the eye. It has, however, a larger instead of a smaller number of vessels distributed over it, although those vessels are too minute to be visible. The shape of the cornea is of the greatest importance: if it were too convex, the rays of light would be brought to a focus before they reached the retina, and thus objects would not be perceived distinctly: if, on the other hand, it were too flat, the rays, instead of meeting before they reached the retina, would not meet even at that point, and thus an equal obstruction to vision would take place. Those who have the former kind of cornea are called short-sighted, those with the latter, long-sighted. The first is a defect very common in youth, and is removed by age; the last is common only in old age. The external surface of the cornea in fishes is almost flat, but its internal surface is more convex. In birds the cornea is required to be so convex that it is removed away from the globe of the eye by means of a short cylinder, which, becoming narrower as it advances forward, permits the cornea which is attached to it to be made more convex.

In fishes the vitreous humour is comparatively small in quantity; the crystalline lens is dense and hard, and instead of being flattened is nearly round; and the aqueous humour is almost wanting. All these changes are rendered necessary by the greater density of the medium through which light is conveyed to fishes; for water, having the same refractive power as the aqueous humour, performs the office which in terrestrial animals is performed by the latter fluid; and the peculiar structure of the lens is intended to make up in refractive power for the density of the medium in which fishes exist.

Within the sclerotic membrane is placed the choroid coat; a membrane of much thinner and more delicate texture, and of a highly organised and vascular nature. Upon this membrane, which lines almost the whole inner surface of the eye, advancing as far forward as the commencement of the iris, the delicate expansion of the optic nerve called the retina is placed; and there is no doubt that the very liberal supply of bloodvessels to the choroid membrane is intended to convey the vital principle to the retina through the medium

of the blood.

The choroid coat secretes a black substance called pigmentum nigrum, which is situated between that membrane and the retina; and it has been supposed that it is placed there to absorb any superfluous rays of light transmitted to the retina, which might confound the sight, and so render objects indistinct. This idea is strengthened by what is observed in the eyes of animals designed to prowl by night, or to obtain their food in situations where few rays of light are admitted. In these animals the pigmentum is not provided, or it is of a light colour. Albinos also are unable to bear a strong light. It was left for M. Desmoulins to shew, that in all animals the colour of the choroid admits of great variation; and that it is of the darkest colour in those which can see in a strong light: hence he concluded, that in animals in whose eyes the pigment is wanting, this membrane is designed to reflect the rays of light from its surface to the back part of the retina, and not to absorb them, as is the case where there is nothing but black pigment. Parts of the inner surface of the choroid are sometimes, however, altogether destitute of pigment, and present at the bottom of the eye the most brilliant yellow, green, and sapphire-blue colours, forming what is called the tapetum lucidum. This appearance is particularly remarkable in the nocturnal and carnivorous tribes; it is sometimes seen even in the ruminants. It exists also in the solipeda, pachydermata, and cetacea; in the dog, wolf, and badger, it is of pure white bordered by blue. The use of the tapetum cannot be misunderstood; for when little light comes to the eye, less must be required to be absorbed, and more to be reflected.

I will now adduce a few facts illustrative of the perfect adaptation of the eye to the situation of every variety of animal, and consequently to the different media through which they receive light; the direct inference from which will, if I mistake not, be, that the Creator of this elaborate instrument of vision must have had the most profound and extensive knowledge, not only of the laws and properties of light, but also of the influence exerted upon it by all other bodies; that, in short, none other than an omniscient Being could have formed the eye.

Flat-fish inhabit the lowest depths of the sea; and, as this situation removes all danger to them from below, there is no necessity for visual organs upon the under surface of their bodies, the invariable position of which, moreover, would render an eye so placed almost entirely useless. Hence both eyes are situated upon the upper surface of their bodies, on which the light from above descends. The cornea, or outer coat of the eye of these animals, is also obviously formed to transmit light coming through a great depth of water.

The various forms of the pupil, or opening in the iris by which light is admitted to the eye, is another provision whereby vision is facilitated, and accommodated to the habits of animals. In animals which climb, such as the felina and simiæ, the pupil, particularly in a bright light, is elliptical, the greater length being in the axis of the body. Animals whose habits render it necessary that they should have a considerable extent of lateral vision, such as whales and the cloven-footed and solid-hoofed genera, have oblong and obliquely transverse pupils.

"The form of the globe (of the eye) varies accord

ing to the medium in which the organ is to be exerted. In man and the mammalia it deviates very little from the spherical figure; in fishes it is flattened on its anterior part; in birds it is remarkably convex in front, the cornea being sometimes absolutely hemispherical. The convexity of the crystalline lens is in an inverse ratio to that of the cornea. Thus in fishes it is nearly spherical, and projects through the iris, so as to leave little or no room for the aqueous humour. The cetacea, and those quadrupeds and birds which are much under the water, have this part of the same form. The aqueous humour being of the same density with the medium in which the animal lives, would have no power of refracting rays of light which come through that medium; its place is therefore supplied by an increased sphericity of the lens. In birds these circumstances are reversed; they generally inhabit a somewhat elevated region of the atmosphere, and the rays which pass through this thin medium are refracted by the aqueous humour, which exists in great abundance. Man and the mammalia, which live on the surface of the earth, hold a middle place between these

two extremes."

The sclerotic coat is of different degrees of thickness, being much thicker at its posterior part than towards its juncture with the cornea. Its thickness in some animals is so great at the back as to be equal to onethird, or one-fourth, of the diameter of the entire eye. This circumstance very much alters the relative position of the internal parts. By means of it, the length of the axis of vision is diminished, and the lens is brought nearer the back of the eye, or the focus of vision. In amphibious animals, which frequently pass from the thin medium of air to the dense medium of water, and vice versa, Blumenbach noticed a particular provision for enabling them to vary the situation of the lens at will, and so to accommodate the axis of vision according to the density of the medium or the distance of objects; without which power they would be but imperfectly adapted for their twofold mode of existence. For this purpose, as in the Greenland seal, the cornea is thin and yielding, the anterior part of the sclerotic is thick and firm, its middle segment thin and flexible, its posterior part thick and almost cartilaginous. The eye is surrounded with very strong muscles, by the action of which the requisite changes in the relative position of the internal parts are accomplished. When the animal is in the air, the axis of vision is shortened by bringing the lens nearer to the back of the globe (which is rendered yielding by the flexibility of the middle segment of the sclerotic), in order to counteract the strong refraction which the rays of light experience in passing from the thin medium of the air into the denser medium of the eye.

But perhaps the most singular adaptation of the eye to the two media of air and water is seen in the anableps, an animal which inhabits the rivers of Guinea, so called from avaßλénw [anablepo], to look up, because it can see above the water and in it at the same time. The orbit or socket of the eyeball extends so far above the head, that the eye, as the animal swims near the surface, is partly in and partly out of the water, and all its internal parts correspond with this curious external conformation. The iris being partially divided into an upper and a lower portion, there are consequently two distinct pupils; the cornea consists of two globes, an upper and a lower one attached together, but divided by a dark band; the anterior globe, which the animal uses out of the water, is in all respects like the eye of terrestrial animals, adapted to refract rays transmitted through the rare medium of air; the inferior one, which is always under the water, like the eye of aquatic animals, is adapted to refract light transmitted through the denser medium of water. that the refracting power of the upper globe is less than that of the lower.

So

The size of the eye in some animals is very great in

proportion to that of the brain. In many birds it almost equals the brain in weight; whereas in man the latter organ is more than sixty times heavier. This fact is sufficient to shew, that the power of vision must be very variable. Many birds, living high in the regions of the air, whence they seek their prey, would be incapacitated for their modes of existence, unless they had eyes capable of " beholding afar off." The unerring aim of the eagle and the kite is attributable to the lengthened power of vision which these birds possess.

The eye is protected in most animals by an outer covering, called the eyelids. The number of these varies. Many animals have two. All birds, together with the crocodile, turtle, frog, and toad, have three. The use of the third eyelid, or nictitating membrane, is not accurately known. Cuvier says, it is by means of this covering that the eagle is able to look at the sun. It certainly serves to defend the eye, and probably to cleanse its surface. But I wish to call your attention more particularly to this membrane, on account of the very beautiful contrivance by which it is drawn over the eye. The nictitating membrane lies, when not in use, folded up in the inner corner of the eye, over the globe of which it is drawn by two muscles which are expressly appropriated to that function. One of these muscles is necessarily fixed to the lower and back part of the eye, near where the optic nerve penetrates the sclerotic; so that, when acting, the tendon of this muscle would press upon the nerve, and thus suspend the power of vision,† unless some means were taken to divert its course. This is effected by a muscle named, from its shape, the quadratus, which, arising from the upper and back part of the eye, and descending in the direction of the optic nerve, terminates by forming a groove or cylindrical canal. The muscle first mentioned, which moves the nictitating membrane, and is called, from its form, pyramidalis, terminates in a long tendinous chord, which passes towards the membrane through the groove of the quadratus, as through a pulley, and is thus kept completely away from the delicate nerve of vision."

Biography.

THE LIFE OF THOMAS BRADWARDINE, ARCHBISHOP of CANTERBURY.‡

It is very instructive to see how God has always, in spite of ignorance and opposition, preserved to himself a people. We are apt to take an erroneous estimate of the prevalence of piety, because we reckon only that which we can see, and are not willing to believe that the Lord is working out of our sight. Thus Elijah lamented that he and he only remained a worshipper of Jehovah, when there were indeed seven thousand who had never bowed the knee to Baal. We are similarly ready to imagine that for some centuries before the Reformation the light of Divine truth was entirely extinguished: darkness did indeed cover the earth, and gross darkness the people, yet there were those even then upon whom the Lord did arise, and his glory was seen upon them; a succession of faithful witnesses continued ever to prophesy, though frequently clothed in sackcloth,

In the Proteus anguinus the external covering so completely conceals the eye, that it is hardly to be seen. This animal, which dwells in dark caverns, is very sensible to light.

+ Nerves cannot perform their function if pressed upon. A familiar example of this may be given in the ulnar nerve at the elbow, the least pressure of which produces the sensation called pins and needles.

Information respecting him will be found in Milner's Church History, cent. xiv. His life is also prefixed to his works.

against the sin and superstitions of the enemies of God.

I drew up, some time ago, a short narrative of the life and labours of bishop Grosseteste; I would present now to my readers an account of Bradwardine, archbishop of Canterbury, who lived somewhat later, a luminary of his age not inferior to the zealous bishop of Lincoln. His doctrine, according to the testimony of modern Roman Catholic writers, approached that which has since been denominated Protestant.

Thomas Bradwardine was born about the middle of the reign of king Edward I., at Hortfield in Cheshire. He was educated at Oxford, and was a member of Merton college, at that time one of the most famous seats of learning in Europe. Here he devoted himself with the utmost assiduity to study; and paying his chief attention to theology and mathematics, far outstripped his contemporaries in both. In 1525, he filled the office of proctor in the university. His great work "concerning the cause of God against the Pelagians," was first delivered in the form of lectures at Oxford. These he afterwards, while chancellor of the diocese of London, at the request of the students of Merton, enlarged and polished. The publication of this book earned for its author the highest reputation. It was speedily in the hands of all the learned men both in England and on the continent; and Bradwardine was thenceforward known by the title of "the profound doctor." His subject was treated with a mathematical accuracy, and his reasoning was pursued in one connected series of arguments, very different from the discursive remarks of the divines who had preceded him.

The reader may like to see some extracts from this remarkable performance; I select, therefore, a few passages, which will give some notion of the author's views on the important subject of grace. "Every creature is indebted to Almighty God for various gifts; and these gifts may with the greatest propriety be called the grace of God, grace freely given. But with very great thankfulness we ought further to observe, that there is such a thing as a peculiar species of this free grace, which makes a man accepted of God; makes him a friend of God, and dear to him; makes him his child for the present, and a partaker of his glory in heaven. The mischievous Pelagians maintain that this sort of grace is not given freely by God, but is to be obtained by preceding merits. I myself was once so foolish and empty, when I first applied myself to the study of philosophy, as to be seduced by this error. In the schools of the philosophers I rarely heard a single word said concerning grace, unless indeed sometimes an equivocal expression might drop from the disputants, but nothing further. Whereas my ears were assailed the day through with such assertions, as we are the masters of our own free actions; it is in our own power to do well or ill, and to have virtues or vices.' And when I heard those parts of the Scriptures read in the Church which extol the grace of God, and lower the free-will of man, for example, 'It is not of him that willeth, or of him that runneth, but of God that sheweth mercy,' and many similar passages,-this doctrine of grace was very disagreeable to my ungrateful mind. But afterwards I began to perceive

some few distant rays of light respecting this matter. I seemed to see, but by no means clearly, that the grace of God is prior, both in nature and in time, to any good actions that men can possibly perform; and I return thanks to God, from whom proceeds every good thing, for thus freely enlightening my understanding. St. Augustine confesses that he himself had been formerly in a similar mistake. 'I was once,' says he, 'a Pelagian in my principles; I thought that faith towards God was not the gift of God, but that we procured it by our own powers, and that then, through the use of it, we obtain the gifts of God; I never supposed that the preventing grace of God was the proper cause of our faith, till my mind was struck in a particular manner by the apostle's argument and testimony: What hast thou that thou hast not received, and if thou hast received it, why dost thou glory as if thou hadst not received it?' In this whole business I follow the steps of Augustine. The great point to be maintained is, that God gives his grace freely, in the strictest sense of the word, and without merit on the part of man. For if God did not bestow his grace in this perfectly gratuitous manner, but on account of some subordinate contingent uncertain cause, he could not possibly foresee how he should bestow his free gifts. The word grace evidently implies that there is no antecedent merit. And in this way the apostle to the Romans appears to argue, when he says, And if by grace, then is it no more of works: otherwise grace is no more grace. Now to him that worketh is the reward not reckoned of grace, but of debt.' All this is perfectly intelligible, even in the conduct of liberal and magnificent human characters. They frequently bestow their gifts from a pure spirit of liberality, without the smallest previous claim on the score of merit. And shall not God, whose perfections are infinite, do more than this? St. Paul says, that God commendeth his love to us in that while we were yet sinners, Christ died for us: and that when we were enemies we were reconciled to God by the death of his Son. St. Paul was in a peculiar manner a child of grace with gratitude, therefore, he honours and extols its efficacy in all his epistles; and particularly in his epistle to the Romans throughout he defends his doctrines with great precision and copiousness. Every mouth,' says he, must be stopped, and all the world become guilty before God. By the deeds of the law no flesh can be justified. Man must be justified freely by his grace. By grace are ye saved through faith, and that not of yourselves, it is the gift of God; not of works, lest any man should boast.' The Pelagians produce such Scriptures as these: The Lord is with you, while ye be with him; and if ye seek him, he will be found of you' (2 Chron. xv. 2). Turn ye, ... and I will turn unto you' (Zech. i. 3). From which they would infer, that the grace of God is proportioned to the merits of men. But all this would be to no purpose, if they would but compare one Scripture with another; for example: Turn us, O God of our salvation' (Ps. lxxxv. 4); and, after that I was turned, I repented' (Jer. xxxi. 19); and,“ turn us unto thee, O Lord, and we shall be turned' (Lam. v. 21). Undoubtedly such expressions as, 'Turn yourselves,' &c. relate to the free power which every

man has to will; but if Pelagius had half an eye, he might see that God, in giving the precept which directs us to turn unto him, influences also the human will, and excites it to action; not, indeed, in opposition to our free choice, but the reverse, as I have all along maintained. Hence it is written, Without me ye can do nothing.' And again,' I laboured more abundantly than they all, yet not I, but the grace of God which was with me.' And lastly, I do not this for your sakes, O house of Israel, but for mine holy name's sake. Then will I sprinkle clean water upon you, and ye shall be clean; and I will cleanse you from your idols. A new heart also will I give you, and a new spirit will I put within you; and I will take away the stony heart, and will give you a heart of flesh.'”

The reader will easily perceive, by what I have here extracted, that the views of Bradwardine on this important doctrine were those which our reformers held when they pronounced, in the thirteenth Article, that "works done before the grace of Christ, and the inspiration of his Spirit, are not pleasant to God, forasmuch as they spring not of faith in Jesus Christ; neither do they make men meet to receive grace, or (as the school authors say) deserve grace of congruity."

Bradwardine's chief taste appears to have been for a sedentary and scholastic life; the splendour of his reputation, however, drew him forth from his beloved retreat, and was the means of leading him into courts and camps. He was appointed confessor to King Edward III., and attended that monarch in his continental wars. It must have been a life strange and unnatural to the contemplative student to witness the strife and tumult, to mingle in the hurry and pomp of Edward's conquests. And when he walked across

some just-won field, between the living and dead, and felt at what a price the glory of triumph was purchased, or when he was called on to address the mailed warriors eager for fresh combats, the scenes of earlier days must have recurred with vivid distinctness to his mind, when, safe in his quiet cell at Oxford, his solitude was not invaded with the din of battles, or perceived them only

At a safe distance, where the dying sound
Falls a soft murmur on th' uninjur'd ear.

Placed, however, by the hand of Providence in the walks of busy life, Bradwardine was solicitous to employ the many talents now entrusted to him to the glory of his divine Master. It was his care to mitigate as far as possible the impetuosity of the king's temper, when immoderately fired with warlike rage, or unbecomingly elated with the advantages of victory. And so much meekness and persuasive eloquence mingled with his addresses to the army, that the soldiers, wrought upon by his earnest admonitions, were more than ordinarily restrained from practising the excesses attendant upon war. In fact, so truly did Bradwardine sustain amid arms the character of an ambassador of peace, and so influential was the spirit which evidently swayed him, that some of the writers of that time do not hesitate to attribute the conquests of the English king rather to the virtues and holiness of his chaplain than to his own conduct, or the prowess of his troops.

His merit was duly appreciated by his own sove

reign. On a vacancy in the see of Canterbury, the monks of that cathedral elected him archbishop. Edward, however, who loved his society, was unwilling to lose him from about his person, and another individual was appointed to the primacy. But as he died in about ten months, the monks again elected Bradwardine, and the king yielded to their desires. In the year 1549 the new prelate was consecrated at Avignon. As, however, with his elevation he had not laid aside his simple habits and humble deportment, there were persons found in the papal court weak enough to attempt on this account to turn him into ridicule. Cardinal Hugh, a nephew of the pope, imagined that he exhibited his wit by introducing into the hall a man habited as a peasant, riding upon an ass, petitioning the pope to make him archbishop of Canterbury. But this brutal jest did not answer the expectations of the contriver. Genius and learning, though destitute of courtly graces, commanded the respect of the pontiff and his council; and while Bradwardine was honoured, his insolent reviler was deservedly rebuked and silenced.

The archbishop did not long survive his elevation. But a few weeks after he was consecrated, and only seven days after his return to England, he died at Lambeth, exchanging the cares of high office and the buffets of a troubled world doubtless for the sweet

felicity of everlasting repose. It may be questioned whether, if he had survived to fill long the metropolitan chair, he would thereby have increased his reputation. "He who before his promotion," says the ecclesiastical historian, 66 was judged of all men the most worthy to preside in the Church, would, in all probability-partly on account of the habits of a studious life, and partly on account of the complexion of the times - have soon been deemed unequal to the office. In the early periods of the Church he might have shone with distinguished lustre; but a pious archbishop, of simple manners, could have done little service to the Church in that age."

Bradwardine is chiefly known by his works; of his personal history, beside the broad facts already stated, little has come down to us; but from the specimen I have given, it will easily be concluded that his piety and his intellectual powers were of no common order. I will add an extract from his writings of a more expressly devotional cast. "O great and wonderful Lord our God, thou only light of the eyes, open, I implore thee, the eyes of my heart, and of others my fellow-creatures, that we may truly understand and contemplate thy wondrous works. And the more thoroughly we comprehend them, the more may our minds be affected in the contemplation with pious reverence and profound devotion. Who is not struck with awe in beholding thy all-powerful will completely efficacious throughout every part of the creation? It is by this same sovereign and irresistible will, that whom and when thou pleasest thou bringest low and liftest up, killest and makest alive. How intense and how unbounded is thy love to me, O Lord! whereas my love, how feeble and remiss! my gratitude, how cold and inconstant! Far be it from thee that thy love should even resemble mine; for in every kind of excellence thou art consummate. O thou who fillest heaven and earth, why fillest thou not this narrow