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turned by Desaguliers, could lift 800 pounds. He rolled up a strong pewter dish with his fingers. He lifted with his teeth and knees a table six feet long, with a half hundred weight at the end. He bent a poker, three inches in circumference, to a right angle, by striking it upon his left forearm; another he bent and unbent about his neck, and snapped a hempen rope two inches in circumference. A few years ago there was a person at Oxford who could hold his arm extended for half a minute, with half a hundred weight hanging on his little finger."* We are also told by Desaguliers of a man who, by bending his body into an arch, and having a harness fitted to his hips, was capable of sustaining a cannon weighing two or three thousand pounds. And not many winters ago, the celebrated Belzoni, when first entering on public life, exhibited himself to the theatres of this metropolis, and by a similar kind of harnessing was capable of supporting, even in an upright position, a pyramid of ten or twelve men surmounted by two or three children, whose aggregate weight could not be much less than 2000 pounds; with which weight he walked repeatedly towards the front of the stage.

The prodigious powers thus exerted by human muscles will lead us to be:hold with less surprise the proofs of far superior powers exerted by the muscles of other animals, though it will by no means lead us to the means of accounting for such facts.

The elephant, which may be contemplated as a huge concentration of animal excellencies, is capable of carrying with ease a burden of between three and four thousand pounds. With its stupendous trunk (which has been calculated by Cuvier to consist of upwards of thirty thousand distinct muscles) it snaps off the stoutest branches from the stoutest trees, and tears up the trees themselves with its tusks. How accumulated the power that is lodged in the muscles of the lion! With a single stroke of his paw he breaks the backbone of a horse, and runs off with a buffalo in his jaws at full speed: he crushes the bones between his teeth, and swallows them as a part of his food.

Nor is it necessary, in the mystery of the animal economy, that the muscles should always have the benefit of a bony lever. The tail of the whale is merely muscular and ligamentous; and yet this is the instrument of its chief and most powerful attack; and, possessed of this instrument, to adopt the language of an old and accurate observer,t " a long-boat he valueth no more than dust, for he can beat it all in shatters at a blow." The skeleton of the shark is entirely cartilaginous, and totally destitute of proper bone; yet is it the most dreadful tyrant of the ocean: it devours with its cartilaginous jaws whatever falls in its way; and in one of its species, the squalus carchariat, or white shark, which is often found thirty feet long, and of not less than four thousand pounds weight, has been known to swallow a man whole at a mouthful.

The sepia octopodia, or eight-armed cuttlefish—the polypus of Aristotle —is found occasionally of an enormous size in the Mediterranean and Indian seas, its arms being at times nine fathoms in length, and so prodigious in their muscular power, that when lashed round a man, or even a Newfoundland dog, there is great difficulty in extricating themselves; and hence the Indians never venture out without hatchets in their boats, to cut off the animal's holders, should he attempt to fasten on them, and drag them under water.

But this subject would require a large volume, instead of occupying the close of a single lecture. Let us turn from the great to the diminutive. How confounding to the skill of man is the muscular arrangement of the insect class! Minute as is their form, there are innumerable tribes that unite in themselves all the powers of motion that characterize the whole of the other classes; and are able, as their own will directs, to walk, run, leap, swim, or fly, with as much facility as quadrupeds, birds, and fishes exercise these faculties separately. But such a combination of functions demands a more complicated combination of motive powers; and what

• Yonng-i Uct. on Nat. PSU. LU8. t Frederiek Mareena. See Shaw, n. II. 4»

it demands it receives. In the mere larve or caterpillar of a cossns, or insect approaching to the butterfly, Lyonet has detected not less than four thousand and sixty-one distinct muscles, which is about ten times the number that belong to the whole human body; and yet it is probable that these do not constitute any thing like the number that appertain to the same insect in its perfect state. The elator noctilucus, or phosphorescent springer, is a winged insect; but it has also a set of elastic muscles, which enable it, when laid on its back, to spring up nearly half a foot at a bound, in order to recover its position. This insect is also entitled to notice inconsequence of its secreting a light, which is so much beyond that of our own glow-worm, that a person may see to read the smallest print by it at midnight. The cicada spumaricL, or spumous grasshopper, is in like manner endowed with a double power of motion; and when attempted to be caught will either fly completely off, at its option, or bound away at the distance of two or three yards at every leap. This insect is indigenous to our own country, and is one of those which in their larve and pupe states discharge, from the numerous pores about the tail, that frothy material upon plants which is commonly known by the name of cuckow-spit.

Crabs and spiders have a strong muscular power of throwing off an entire limb whenever seized by it, in order to extricate themselves from confinement; and most of them throw off also, once a year, their skin or crustaceous covering, and secrete a new one. The muscular elasticity of the young spider gives it, moreover, the power of wings; whence it is often seen, in the autumn, ascending to a considerable elevation, wafted about by the breeze, and filling the atmosphere with its fine threads. The land-crab (cancer ruricola) inhabits the woods and mountains of a country; but its muscular structure enables it to travel once a year to the seacoast to wash off its spawn in the waters. The spawn or eggs thus deposited sink into the sands at the bottom of the sea, and are soon hatched; after which millions of little crabs are seen quitting their native element for a new and untried one, and roving instinctively towards the woodlands.

The hinge of the common oyster is a single muscle; and it is no more than a single muscle in thechama gigas, or great clamp-fish, an animal of the oyster form, but the largest testaceous worm we are acquainted with. It has been taken in the Indian Ocean of a weight not less than 532 pounds; the fish, or inhabitant, being large enough to furnish 120 men with a meal, and strong enough to lop off a hand with ease, and to cut asunder the cable of a large ship.

Nor is the muscular power allotted to the worm tribes less wonderful than that of insects, or its variety less striking and appropriate. The leech and other sucker-worms are as well acquainted with the nature of a vacuum as Torricelli; and move from place to place by alternately converting the muscular disks of their head and tail into air-pumps.

The sucker of the cyclopterus, a genus of fishes denominated suckers from their wonderfully adhesive property, is perhaps the most powerful, for the size of the fish, of any we are acquainted with; and is formed at will, by merely uniting the peculiar muscles of its ventral fins into an oval concavity. In this state, if pulled by the tail, it will raise a pailful of water rather than resign its hold.

The teredo navalis, or ship-worm, is seldom six inches in length, but the muscles and armour with which its head is provided enables it to penetrate readily into the stoutest oak planks of a vessel, committing dreadful havoc among her timbers, and chiefly producing the necessity for her being copperbottomed. This animal is a native of India; it is gregarious, and always commences its attack in innumerable multitudes; every worm, in labouring, confining itself to its own cell, which is divided from that of the next by a partition not thicker than a piece of writing-paper. The seaman, as he beholds the ruin before him, vents his spleen against the little tribes that have produced it, and denounces them as the most mischievous vermin in the ocean. But a tornado arises—the strength of the whirlwind is abroad—the clouds pour down a deluge over the mountains—and whole forests fall prostrate before its fury. Down rolls the gathering wreck towards the deep, and blocks up the mouth of that very creek the seaman has entered, and where he now finds himself in a state of captivity. How shall he extricate himself from his imprisonment ?—an imprisonment as rigid as that of the Baltic in the winter season. But the hosts of the teredo are in motion:—thousands of little augurs are applied to the floating barrier, and attack it in every direction. It is perforated, it is lightened, it becomes weak; it is dispersed, or precipitated to the bottom; and what man could not effect, is the work of a worm. Thus it is that nothing is made in vain; and that in physics, as well as in morals, although evil is intermingled with good, the good ever maintains a predominancy.

LECTURE XI.

OK THE BONES, CARTILAGES, TEETH, ARTICULATION, INTEGUMENTATION, HAIR, WOOL, SILK, FEATHERS, AND OTHER HARD OR SOLID PARTS OF THE ANIMAL FRAME.

In a former lecture we took a general survey of the characteristic features that distinguish the unorganized from the organized world, and the vegetable kingdom from the animal: we examined into the nice structure of plants, and the resemblances which they bear to the animated form. In our last lecture we proceeded to an inquiry into the nature of the living principle, took a glance at a few of the theories that have been invented to explain its essence and mode of operation, and contemplated the origin and powers of the muscular fibre, which may be denominated its grand executive organ.

The muscles of an animal, however, are not the only instruments of animal motion; the bones, cartilages, and ligaments contribute very largely to the action, and the skin is not unfrequently a substitute forthe muscle itself. These, therefore, as well as a variety of other bodies minutely connected with them, or evincing a similarity of construction,—as the teeth, hair, nails, horns, shells, and membranes,—are now to pass under our review, and are entitled to our closest attention; and I may add, that their diversity of uses and operations, and the curious phenomena to which they give rise, are calculated to afford not less amusement than instruction.

I had occasion to remark lately,* that lime is a substance absolutely necessary to the growth of man. It is, in truth, absolutely necessary to the growth of almost all animals; even soft-bodied or molluscous worms, except in a few instances, are not free from it; nay, even infusory animals, so minute as to be only discerned by the microscope, still afford a trace of it in the calcareous speck which constitutes their snout; but it is in the bones and shells of animals that lime is chiefly to be found; and hence those animals possess most of it in whom these organs are most abundant.

Bone, shell, cartilage, and membrane, however, in their nascent state, are all the same substance, and originate from a viscid fluid, usually supposed to be the coagulable lymph, or more liquid part of the blood; which, secreted in one manner, constitutes jelly, or gelatine, a material characterized by its solubility in warm water, heated to about half the boiling point; and secreted in another manner, forms albumen, or the material of the white of the egg, characterized by itii coagulating instead of dissolving in about the same heat: the difference, however, between the two, consisting merely, perhaps, in the different proportion of oxygen they contain. Membrane, is gelatin, with a small proportion of albumen to give it a certain degree of solidity; cartilage

• Serin i. Lect. Ti. On Geology, p. 73, and paralm; and Lect. TilL On Organlied Dodiea, and tba Structure of Plants compared to that of Animal*, p. 81.

is membrane, with a larger proportion of albumen to give it a still greater degree of solidity; and bone and shell are mere cartilage, hardened by the insertion of lime into their interior, the lime being secreted for this purpose by a particular set of vessels, and absorbed by the bony or shelly rudiments in their soft state. And hence any substances which, like the mineral acids, for example, have a power of dissolving the earthy matter of the two last, and of leaving the cartilage untouched, may be readily employed as reagents, to reduce them to their primary softness: and it was by this means that Cleopatra, as we are told by Pliny, dissolved one of the costly pair of pearls that formed her earrings, each of which was valued at upwards of eighty thousand pounds (ccntiet seslertium), at a feast given to Mark Antony, and then presented it to him in a goblet, with an equal mixture of wine.*

In the adult state, however, as well as in the embryo state, it is necessary that the bones, like every other substance of the animal frame, should be punctually supplied with the elementary matter, or the means of forming the elementary matter, of which it essentially consists, the old matter of every kind being worn out by use, and carried away by a distinct set of vessels, called lymphatics or absorbents. It is the office of the digestive organs to receive such supply from without, and to prepare it for the general use. And hence, if we could conceive it possible for these organs, or any organs dependent upon them, to be so peculiarly diseased as to be incapable of preparing or conveying to the bones a sufficient quantity of lime (of which some portion is contained in almost every kind of food) to supply the place of that which is perpetually passing off, the necessary consequence would be, that the bones would progressively lose their hardness,and become cartilaginous and pliable. Now we sometimes do meet with the digestive or the secretory organs affected by such a kind of disease, and that both in children and adults. In children it is more common, and is called Rickets; in grown persons it is simply called a Softness or The Bones, or Mollities Ossicm. In the former case, the softened spine becomes bent from the weight of the head, and other extremities, which it is now no longer able to sustain, while the chest and most of the limbs partake of the general distortion. In the latter case many of the bones are sometimes reduced to imperfect cartilages, and can be bent and unbent in any direction.

Lime, however, is never found in the animal system in its pure state, and is certainly never introduced into it in such a state. It is usually combined with some acid, either the phosphoric, in which case the compound is called phosphate of lime; or carbonic acid gas, when it is called carbonate of lime, or common chalk.

It is of no small importance to attend to the nature of these two acids; for it is the difference between them that chiefly constitutes the difference between bones and shells; bones uniformly consisting of a larger proportion of phosphate of lime, or lime and phosphoric acid, and a less proportion of carbonate; and shells of a larger proportion of carbonate of lime, and a less proportion of phosphate. There are a few other ingredients that enter into the composition of both these substances, and which are chiefly obtained from the materials of common salt, as sulphuric acid and soda; but the proportions are too small to render it necessary to dwell upon them in a course of popular study. Bones, shells, cartilages, and membranes may therefore be regarded as substances of the same kind, differing only in degree of solidity from the different proportions that they possess of albumen and salts of lime.

Teeth, horn, coral, tortoise-shell, fish-scales, and the crustaceous integuments of crabs, millepedes, and beetles, are all compounds of the same elements combined in different proportions, and rendered harder or softer as they possess a larger or smaller quantity of calcareous salts; ivory and the

* This was on a trial who could give the most sumptuous banquet. Munacf ui Ptancua was the arbiter. The expense of Mark Antony'r, elready bestowed, had been valued at just the price of this single peart. Cleopatra was proceeding to diwulve its fellow, when she was suddenly stopped by the umpire, who de. elated the victory to be hers. l'im. Hist- Nat lib li. 33.

enamel of teeth possessing the largest quantity, and consisting almost exclusively of phosphate of lime, with a small proportion of animal matter.

The gelatin and albumen are unquestionably generated in the animal system itself from the different substances it receives under the form of food; and it is curious to observe the facility and rapidity with which some animals are capable of producing them. The gastrobranchus cacus, or hag-fish, a small lamprey-like animal of not more than eight inches long, will convert a large vessel of water in a short period of time into size or mucilage, of such a thickness that it may be drawn out in threads. The form and habits of this little animal are singular: Linnaeus regarded it as a worm; but Bloch has removed it, and with apparent propriety, into the class of fishes. It is a cunning attendant upon the hooks of the fisherman; and as soon as it perceives a larger fish to be taken, and by its captivity rendered incapable of resistance, it darts into its mouth, preys voraciously, like the fabled vultures of Prometheus, on its inside, and works its way out through the fish's skin.

But though gelatin and albumen are unquestionably animal productions, the one a secretion from the blood, and the other a constituent principle of it, there is a doubt whether lime ought ever to be regarded in the same character. A very large portion is perpetually introduced into the stomach from without. In our lecture on the analogy between the structure of plants and of animals,* I had occasion to observe, that it forms an ingredient in common salt; not, indeed, necessarily so, but from the difficulty of separating the other ingredients from their combination with it: yet it enters not more freely into common salt than into almost every other article, whether animal, vegetable, or mineral of which our diet is usually composed. And upon this common fact it is more generally conceived, at present, to be a substance communicated to the animal frame, than generated by it.

This opinion, however, is by no means established; and there are many circumstances that may lead us to a contrary conclusion. Though almost every kind of food contains some portion of lime, it by no means contains an equal portion; and yet we find that a healthy young animal, whatever be the sort of food on which it is fed, will still provide lime enough from some quarter or other to satisfy the demand of its growing bones, and to maintain them in a due degree of solidity and hardness.

Again, the soil of some countries, as the mountains of Spain, for example, consists almost entirely of gypsum or some other species of limestone; while in other countries these are substances very rarely to be met with. It is a curious fact, that in that vast part of the globe which has been latest discovered, and to which modern geographers have given the name of Australia, comprising New-Holland and the islands with which its shores are studded, not a single bed or stratum of limestone has hitherto been detected, and the builders are obliged to make use of burnt shells for their mortar, for which I have lately advised them to substitute burnt coral.f Now, it would be natural to suppose that the animals and vegetables of such a country would partake of the deficiency of its soil, and that the shells and bones which it produces would be less compact in their texture than those of other countries; yet this supposition is not verified by fact: nature is still adequate to her own work; the bones of animals are as indurated and perfect in these regions as in any parts of the old world; while the shells are not only as perfect, but far more numerous; and the frequent reefs of coral, altogether an animal production, that shoot forth from the shores in bold and massy projections, prove clearly that a coral rock, largely as it consists of lime, forms the basis of almost every island.

The prodigious quantity of lime, moreover, that is secreted by some animals at stated periods, beyond what they secrete at other times, seems to indicate a power of generating this earth in their own bodies. The stag, elk, and several other species of the deer-tribe, cast their antlers annually, and

• Series i. Lect. viii.

t II is understood that some beds of chalk have since been discovered on the farther side of the Blue Mountains, but none is still to be traced on the tnth< r si* in any of the •etllements of the colonv.

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