as an intellectual provision for the entertainment, of their declining years. We have, hitherto, refrained from touching upon religious or political subjects, partly from a want of inclination towards those topics, and partly on account of the repugnance naturally felt by the Drapers' Association to insert anything which might tend to give offence. We are now, however, of opinion that, in this extraordinary age of transition, it is the bounden duty of every man to investigate narrowly the social circumstances which surround him, that he may be the better prepared to follow honestly and firmly that line of conduct pointed out by his conscience, as the path of duty. But our remarks upon religion and politics will be marked by no sectarian spirit of controversy, and embittered by no violent or acrimonious zeal for any of the ephemeral parties who now trumpet forth their widely different opinions with so much sound and fury. In a mild and catholic breadth of goodwill to all, we shall endeavour to excel; in the pursuit of truth we shall spare no exertion; and whilst we criticise an action, we shall also consider the motive, at least, so far as circumstances will permit of such a consideration. For, if the motive be honest, if men act up to what they truly believe to be right, there will be some redeeming quality even in their most hurtful actions; but if a bad design should be eventually beneficial in its effects upon mankind, we must attribute the happy result to the benevolent interference of the Disposer of all things, and not to the human projector, whose want of power alone prevented him from working harm. Such is the spirit in which we shall criticise; such is the law by which we would be judged; so that if, through miscalculation of our resources, our undertaking should not succeed, the failure may be attributed to a flaw in our judgments, but not to an error of our hearts.

ON THE EVIDENCES OF UNITY AND DESIGN DISPLAYED IN THE ORGANISATION OF ANIMALS.

BY A LECTURER ON PHYSIOLOGY.

THE mechanical parts of animal bodies, such as the shells of the mollusca and the bones of the vertebrata, have in all ages attracted the notice of reflecting minds, not less on account of their

perfect mechanism than of the striking marks of design displayed in the adjustment of their various component parts. Attention has, however, been fixed almost exclusively on the larger, more obvious, and, if the expression be permissible, the

coarser portions of these formations. But if the more concealed structure be scrutinised-if, that is to say, the microscopic texture be examined, and the chemical composition be considered, we shall find equal, if not superior, grounds for admiration; and inasmuch as these passive organs of motion, for such they are, minister to the mechanical, and not to the more strictly vital functions of the animal frame, their construction admits of being more easily studied, and their offices of being more easily comprehended: they are thus well adapted for popular illustration.

If a piece of wheaten straw be examined, it is seen to consist of a hollow tube or cylinder, perfect in its form, rigid in its walls, and yet light as to weight: if further investigated, it is found to contain, in addition to the carbon with which all vegetable substances abound, one of the hardest materials in naturesilica, or flint; so that when a wisp of straw has been exposed for a short time to an intense heat it presents a metallic aspect. Now, if it be asked, what is the end or design of all these provisions? it may be answered, that it is to give strength and resistance, with economy of material; for although nature never withholds what is requisite, she never bestows what is superfluous-all her works are subjected to fixed, unerring, and perfect laws. We have called attention to this simple mechanism, because it offers a typical representation of a principle extensively exhibited in the bones of animals. It matters not whether the massive bones supporting the huge body of the elephant, or the fragile framework sustaining the humming bird in its flight, be inspected, it is invariably found that the greatest possible amount of resistance is combined with the least possible amount of material. In all birds this principle is strikingly seen. We have now lying before us one of the hollow bones of the ostrich; it forms a beautiful cylinder, which, enlarged in the transverse diameter, increases the resistance to fracture without corresponding augmentation of weight. In addition to this mechanism, which is common to all animals, there is in the case of birds this peculiar provision, that the bones are in their interior filled with air instead of with marrow, an evident means of lightening these organs, and thus promoting the powers of flight.

If from the entire bone the anatomist turns to its individual parts, in the midst of apparent confusion he detects order, contrivance, perfection. It is related of Brunelleschi, the celebrated architect of the cathedral of Santa Maria at Florence, that, on being selected to complete this magnificent edifice, which had been commenced by Arnulfo di Lapi, and perceiving that the existing foundation could not support a dome with solid walls, he conceived the idea of copying the mechanical texture of the

human skull, the bones of which are each composed of two plates connecting by the light fibrous matter, constituting the diploe. The plan was realised; and this noble dome, second only to that of St. Peter's, consists of an inner and outer wall with an intervening space, a contrivance which was subsequently adopted by Michael Angelo in his great master-work at Rome. This is only one of a multitude of similar instances in which the great promoters of human art have either designedly copied, or accidentally imitated, the exquisite formations of animal bodies.

The bones of the limbs display, when divided, a complex series of arches and fibres, constituting that most delicate tissue named by anatomists the cancelli, the form and disposition of which, varying in the different divisions of the skeleton, as palpably depend on the uses to be fulfilled. For the purpose of illustration, we have selected that part of the human thigh-bone which is placed close to the hip-joint. (See the adjoining figure.)

A little reflection will enable our readers to comprehend this elaborate formation: if a person falls from a height on his feet or knees, the stress of the concussion is experienced in what is called the neck of the thigh-bone. Now, in order to resist the shock, a special set of fibres (a) is provided, and, in the vast majority of cases, fracture is thus prevented. But it often happens, that in suddenly falling the great projecting process named trochanter major (d) is struck; and on looking at the figure, a series of fibrous plates (b) is seen to oppose the force acting in this new direction. Again, the part which, under all the above circumstances, must bear the principal strain, is evidently that where the shaft or stem of the bone joins the neck; and it is precisely this segment, which is strengthened by a beautiful series of concentric arches (c), presenting, in connexion with the

fibres a and b, a mechanism as perfect in its adaptation as it is palpable in its design.

Satisfactory as are the evidences of a controlling intelligence thus recognisable by the unaided senses, there is something even more deeply interesting to the cultivated mind in the contemplation of that secret mechanism which, lying as it were beneath the surface of the visible anatomy, requires the powers of the microscope for its revelation. This instrument, by disclosing, in the hands of Schwann, the ultimate, that is, the essential structure of animal and vegetable formations, has rendered to the science of organisation services as splendid as those conferred on astronomy by the telescope; for, as the latter, by displaying to Galileo the revolutions of the satellites of Jupiter, prepared the way for the discovery of the law of gravitation and of the true motions of the heavenly bodies; so it may be affirmed of the former instrument-that by demonstrating, as it has done, the true form of organic matter, namely, the nucleated cell, the foundation has been laid for some second Newton to discover the law of nutritive action.

We have said, that the interior of bones presents to the eye a loose spongy texture, which in life is filled by the medulla or marrow; but the outer walls seem to be perfectly solid-in fact, there is no organic substance, save ivory, which appears to be more compact. Both one and the other, however, that is, dense bone and denser ivory-are hollowed into millions of canals, invisible it is true to the naked eye, but not the less on this account having a true existence. By the aid of their imperfect microscopes, the older observers had detected some part of this intricate texture of bone; one of the most striking characters of which consists of a vast multitude of minute passages, named after a celebrated anatomist, the canals of Havers: these passages (v, e) have a diameter varying from the 1-2500th to the 1-200th of an inch, the mean size being about 1-500th.

By referring to the appended figure, which is a scheme of the microscopic structure of bone, there are seen on the surface of the transverse section (a, b, c, d), the minute orifices (i) of the above-named Haversian canals, which run principally in a longitudinal direction (v, e), having numerous cross branches of communications between them.

In addition to these passages, there are other excavations (not represented in our drawing), of a more or less oval form, called lacunæ, having a short diameter of 1-3600th, and a long diameter of 1-1800th of an inch. There are, even in connexion with these void spaces, extremely minute and additional passages (the canaliculi of Muller), of a diameter varying from the 1-12000th to the 1-2000th of an inch. Lastly, lying in the interstices of all these excavations, that is to say, of the Haversian canals, the lacunæ and the canaliculi, is the true solid bony matter, consisting of very fine grains of 1-10000th inch diameter.

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Such being the true character of the apparently solid bone, the question immediately suggests itself, What is the use of this remarkably complex arrangement? If we were to rest content with the account given by physiological writers, we should say that the Haversian canals are for the purpose of carrying the blood-vessels into the interior, (for the bones are very vascular organs); or, at most, that they have the additional office of tying together the minute osseous plates, like so many rods or pins; and that the lacunæ and canaliculi are merely subservient to the support of the bone by conveying nutricious fluids. mitting that the passages described are connected with nourishment, we regard that as their secondary office; their essential object being, although hitherto not so described, mechanical. The interpretation of this complex structure we hold to be as follows: The Haversian canals are a series of hollow cylinders, each being a repetition of the central hollow seen in the long bones of the limbs, whilst each of the lacunæ is, on a minute scale, the type of the large spaces seen with the naked eye in the cancellated texture; so that we have here carried out, to the ultimate structure, the great principle displayed in the whole osseous system-the combination of strength and lightness.

We have only space for a few remarks relative to the chemical composition of bone. It is obvious, that organs supporting the superincumbent weight of the body, and resisting like so many levers the enormous force of the muscles, must be momentarily exposed to shocks and concussions in the varied occupations of life, which, if not checked by a high degree of elasticity, would constantly endanger the occurrence of fracture. To prevent mischief like this, bone is elastic-nay, a much harder substance, ivory or dental substance, is remarkably resilient-and, in each