and not natural philosophers. Hence they were often found ignorant of details; and frequently were misled by imaginary relations, not the result of scientific inquiries, but of speculative theology. The consequence was, that real philosophers got a prejudice against a topic, which, to be treated safely, requires to be managed very delicately; errors of no little absurdity were committed; and it is hard to say if scoffers did not, upon the whole, gain more than worshippers, by many of those wellmeaning, but ill-qualified authors. Mr Stewart (Outlines, § 283,) justly remarks, upon the abuse, as well as the use of the speculation concerning Final Causes; and regards an explanation of both, as still being a desideratum in science. But he observes, that it is no longer so necessary as formerly to banish this inquiry from Physics, because the true method of philosophizing is generally understood, and the danger of confounding Final with Physical Causes, is far less imminent. He remarks, most properly, that in Anatomical inquiry, every one proceeds upon the maxim, that nothing in any animal's body was made in vain, and refuses to rest satisfied, as long as the use of any part or function remains unexplained; thus admitting, that Final Causes may not only be sound inferences from the known truths of philosophy, but may be guides in discovering new ones. The anecdote which Mr Boyle gives respecting Harvey's grand discovery, is a striking illustration of this doctrine; and might far better have served the purpose of Paley's argument, than the remark which he makes on Dolland's discovery, which we have above commented upon. 'I remember,' says Mr Boyle, that when I asked our famous Harvey what were the things that induced him to think of the circulation of the blood? he ' answered me, that when he took notice that the valves in the ' veins of so many parts of the body were so placed that they gave a free passage to the blood towards the heart, but oppo'sed the passage of the venal blood the contrary way; he was 'incited to imagine, that so provident a cause as Nature had not 'placed so many valves without design; and no design seemed more probable, than that, since the blood could not well, because of the interposing valves, be sent by the veins to the limbs, it should be sent through the arteries, and return through the • veins, whose valves did not oppose its course that way.' It is not, indeed, to be wondered at, that the structure of the body should turn men's thoughts towards these speculations, in modern times, when even the ancient philosophers, averse as they were to the inductive methods, were led by it to philosophize far more soundly than on almost any other subject. Faciliusque intelligetur, a diis immortalibus hominibus esse provisum,' says

Cicero, arguing against the Epicurean doctrines, si tota homi'nis fabricatio perspecta, omnisque humanæ naturæ figura atque perfectio. (De Nat. Deorum. Lib. ii.)

That the subject, then, is as strictly scientific, as it is noble and delightful, there can be no doubt; and it is truly gratifying to find it treated according to its high deserts. The treatise before us is not the work of a declamatory moralist, or a sentimental enthusiast, or a narrow-minded bigot; but of a man of profound science, who does homage to the truths of religion, because they cross the path of his philosophic inquiries; who bears the testimony of facts to the doctrines of a sublime theology, which those facts inculcate, along with the other lessons he had gone in quest of. It is not the priest who leaves the temple to gather flowers for its adornment; but the sage who brings to the altar his offering, from the fruits he has so richly collected, of an all-pervading and supreme intelligence.

It is inconsistent with our present purpose to offer any analysis of this admirable Paper. It is divided into six chapters, after the Introduction. In these are successively treated, the Architecture of the Skull; the Mechanism of the Spine; the structure of the Bones, and Joints of the Extremities; the Cordage of the Tendons; the Muscles and Muscular Motion; and the works upon such subjects which have before appeared. We shall do no more than give a specimen or two, rather to exhibit the manner in which the discourse is conducted, than to show even a sample of its contents.

The following passage is the beginning of the Chapter upon the Skull:

It requires no disquisition to prove that the brain is the most essential organ of the animal system, and being so, we may presume that it must be especially protected. We are now to inquire how this main object is attained?

We must first understand that the brain may be hurt, not only by sharp bodies touching and entering it, but by a blow upon the head which shall vibrate through it, without the instrument piercing the skull. Indeed, a blow upon a man's head, by a body which shall cause a vibration through the substance of the brain, may more effectually deprive him of sense and motion than if an axe or a sword penetrated into the substance of the brain itself.

Supposing that a man's ingenuity were to be exercised in contriving a protection to the brain, he must perceive that if the case were soft, it would be too easily pierced; that if it were of a glassy nature, it would be chipped and cracked; that if it were of a substance like metal, it would ring and vibrate, and communicate the concussion to the brain.

Further thoughts might suggest, that whilst the case should be made firm to resist a point, the vibrations of that circular case might

be prevented by lining it with a softer material; no bell would vibrate with such an incumbrance; the sound would be stopped like the ringing of a glass by the touch of a finger.

If a soldier's head be covered with a steel cap, the blow of a sword which does not penetrate will yet bring him to the ground by the percussion which extends to the brain; therefore, the helmet is lined with leather, and covered with hair; for, although the hair is made an ornament, it is an essential part of the protection: we may see it in the head-piece of the Roman soldier, where all useless ornament being despised as frivolous, was avoided as cumbrous.

We now perceive why the skull consists of two plates of bone, one external, which is fibrous and tough, and one internal, dense to such a degree that the anatomist calls it tabula vitrea (the glassy table.)

Nobody can suppose this to be accidental. It has just been stated, that the brain may be injured in two ways; a stone or a hammer may break the skull, and the depressed part of the bone injure the brain; whilst, on the other hand, a mallet struck upon the head will, without penetrating effectually, deprive the brain of its functions, by causing a vibration which runs round the skull and extends to every portion of its contents.

Were the skull, in its perfect or mature state, softer than it is, it would be like the skull of a child; were it harder than we find it is, it would be like that of an old man. In other words, as in the former it would be too easily pierced; so, in the latter, it would vibrate too sharply and produce concussion. The skull of an infant is a single layer of elastic bone; on the approach to manhood it separates into two tables; and in old age it again becomes consolidated. During the active years of man's life the skull is perfect; it then consists of two layers, united by a softer substance; the inner layer is brittle as glass, and calculated to resist anything penetrating; the outer table is tough, to give consistence, and to stifle the vibration which there would be if the whole texture were uniform and like the inner table.

The alteration in the substance of the bones, and more particularly in the skull, is marvellously ordered to follow the changes in the mind of the creature, from the heedlessness of childhood to the caution of age, and even the helplessness of superannuation.

The skull is soft and yielding at birth; during childhood it is elastic, and little liable to injury from concussion; and during infancy, and up to the period of maturity, the parts coming in contact with the ground, are thicker, whilst the shock is dispersed towards the sutures (the seams or joinings of the pieces), which are still loose; but when, with advancing years, something tells us to give up feats of activity, and falls are less frequent, the bones lose that nature which would render concussion harmless, and at length the timidity of age teaches man that his structure is no longer adapted to active life.'

He thus, in the second chapter, describes another provision for the protection of the brain, namely, the curved form of the spine

'A steel spring being perfectly straight, if pressed betwixt the hands

from its extremities, will resist, notwithstanding its elasticity, and when it does give way, it is with a jerk.

Such would be the effect on the spine if it stood upright, one bone perpendicular to another, for then, the weight would bear equally, and the spine would yield neither to one side nor another; and, consequently, there would be a resistance from the pressure on all sides being balanced. We, therefore, see the great advantage resulting from the human spine being in the form of an italic; it is prepared to yield in the direction of its curves, the pressure is of necessity more upon one side of the column than on the other, and its elasticity is immediately in operation without a jerk. It yields, recoils, and so forms the most perfect spring, admirably calculated to carry the head without jar, or injury of any kind.

The most unhappy illustration of all this is the condition of old age; the tables of the skull are then consolidated, and the spine is rigid; and if an old man should fall with his head upon the carpet, the blow, which would be of no consequence to the elastic frame of a child, is to him fatal; and the rigidity of the spine makes every step he takes vibrate to the interior of the head, and jar on the brain.' The third chapter thus beautifully opens:

That the bones, which form the interior of animal bodies, should have the most perfect shape, combining strength and lightness, ought not to surprise us when we find this in the lowest vegetable production.

In the sixteenth century, an unfortunate man, who taught medicine, philosophy, and theology, was accused of atheistical opinions, and condemned to have his tongue cut out, and suffer death. When brought from his cell before the Inquisition, he was asked if he believed in God. Picking up a straw which had stuck to his garments, If,' said he, there was nothing else in nature to teach me the existence of a 'Deity, even this straw would be sufficient!'

A reed, or a quill, or a bone, prove that strength is given with the least possible expense of materials. The long bones of animals are, for the most part, hollow cylinders, filled up with the lightest substance, marrow; and in birds the object is attained by means (if we may be permitted to say so) still more artificial. It must have been observed, that the breast-bone of a fowl extends along the whole body, and that the body is very large compared with the weight; this is for the purpose of rendering the creature specifically lighter and more. buoyant in the air; and that it may have a surface for the attachment of muscles, equal to the exertion of raising it on the wing. This combination of lightness with the increase of volume, is gained by air-cells extending through the body, and communicating by tubes between the lungs and cavities of the bones. By this means, the bones, although large and strong to withstand the operation of powerful muscles upon them, are much lighter than those of quadrupeds.'

Let these few extracts suffice for the object of directing the reader's attention to the original Treatise, a perusal of which will amply repay him, whether he be a man of science, or a novice.

We have been prevented, by want of figures, from giving any specimen of the scientific portions of the work. These must be enjoyed by a recourse to the Treatise itself.

We cannot, however, dismiss this subject, without expressing our delight at the perfect success of the Society's great design of covering, as it were, the country with knowledge, even as the waters cover the sea. Here lies an instance before us, worth a thousand arguments, to prove the practicability of this scheme, and the triumphant removal of all the obstacles that were expected to oppose its execution. The work we are contemplating, is profoundly scientific, and yet perfectly popular; any attentive reader may follow, and comprehend, and remember its contents. The treatise appears at its regular time, each month having seen two published. Then its cheapness exceeds all former experience. Compare it with Mr Paxton's edition of Paley. Three of his pages go into one of the Library; consequently, his two volumes can be printed in five of the treatises, and a little more-or, allowing for the figures, in six. His book costs four-and-twenty shillings; the six treatises would cost threeor they are eight times cheaper. The figures in the Animal Mechanics are beautiful; the drawing is very spirited and fine, indeed evidently by a master's hand, and far superior to the figures of Mr Paxton-the engraving, though in wood, is full as good. There are about thirty of these figures-so there would be 180 for three shillings. Mr Paxton's thirty-seven plates contain 123, reckoning every single thing a separate figure, though sometimes four or five would go into the space of one; but even counting them all, there are half as many more in the Library. The page of Mr Paxton, too, contains a good deal more than the ordinary sized octavo page; for we have cited one book in this article, one hundred and forty of whose pages go into the space of the sixpenny treatise lying before us! To all this let it be added, that these treatises are published periodically; * a circumstance which, in every other case, makes the volume dearer instead of cheaper-and it will surely be allowed, that never difficulty was more completely removed than the one of price, which was at first expected to be a fatal impediment in the way of this grand design of Universal Knowledge. The circulation of the Library, accordingly, proceeds rapidly increasing. Al

* Even page for page, the Library is far cheaper, independent of its superior quantity of matter. A number of the treatises equal to Mr Paley's book, that is 16, would cost only eight shillings, that is a third, and would contain 480, instead of 123 drawings.