Page images
PDF
EPUB

noise of artillery. The crater incloses | tercourse, and the examination of the sand six mouths-two ejecting smoke, and hy- thrown up by the whirlpool of Charybdis, 'drochloric and sulphurous acid gases- they returned to Sicily, and entered the the third vomiting fiery stones with the harbor of Jardini, having found in the noise of a heavy surf. The other three neighboring bay of Taormine many objects mouths exhibit only intermittent eruptions, of interest. two of them kindling and going out at the same time. The third, which gives fewer eruptions than the rest, is distinguished by the most formidable detonations, and by the highest jets of burning rocks and cinders. When the night had closed in upon them, a magnificent eruption took place. The three mouths played together, reflecting the red brightness of the lava, and revealing again the triple inclosure of the crater. In almost total darkness, they accomplished a dangerous descent; and, on their return to their boat, the sea was kindled into a blaze of light by the phosphorescent luminosity emitted by the crustaceans, annelids, and medusæ, who, at the reproductive season, emit a luminous flash at each muscular contraction. The waves, breaking against the shore, encircled it with a shining border, while every cliff had its wreath of fire. A bucket of the sea-water was like a mass of melted lead when poured into the sea. Professor Ehrenberg supposes that some annelids have a special organ for producing light, like the female glow-worm, which has a luminous apparatus in its abdomen, in order to show to her mate the place where she is to be found. This explanation, however, may be questioned; for MM. Audoin and Milne Edwards saw the phosphorescent fluid of the Pholades flow in a stream along the bottom of a vessel filled with alcohol, and afterwards combine into a luminous stratum without losing any of its brightness.

In their voyage of sixty miles from Stromboli to Messina, our travelers found curious specimens of the Medusidæ, and among others the Vellela, a lovely zoophyte, with its dark blue umbrella, having on its lower surface numerous suckers containing air which ballasts them on the surface of the water, while the wind striking their vertical plates, like so many sails, enables them to float in large numbers on the ocean.

Having had no society during four months, MM. Edwards and Quatrefages had the good fortune to meet at Messina the celebrated traveler Ruppel, M. Tardi, Dr. Cocco, and Dr. Cupari of Pisa; and after some days of pleasant scientific in

Without attempting to give our readers an account of the important researches in Embryology, which M. Edwards began so early as 1833, we shall state merely the general result which he obtained. In his first Memoir on the subject, he showed that the metamorphoses in the form of different crustaceans always tend to impress upon the animal a more special character, and that they follow one another in a determinate order, the most important characters being first manifested. That is, the embryo acquires first the characters of the subdivision to which it belongs, and then in succession those of the class, family, tribe, genus, subgenus, and species. In order to illustrate this, our author follows through all the phases of its existence the large Terebella, (Terebella annulosa,) an animal six or seven inches long, showing successively how the embryo belonged to the great division of the Articulata, then to that subdivision of it in which the body is divided into segments, then that it is a true annelid, and, finally, that it is a tubicolous worm. "Investigate it," he adds, "a little longer, and we shall be able to recognize its genus and its species." This is very much the same as if, being interested in obtaining detailed information respecting any individual, we were first to learn that he was born in the old continent; next, that he was a European; then, that he was a Frenchman; then, a Parisian; that he lived in such a street, in such a number; that he bore such and such a name; and, we may add, that he would be very glad to see M. Quatrefages.

Our author devotes the rest of his fifth chapter to an account of the acquisitions and researches of M. Blanchard. He had collected above 2000 species of insects, represented by at least 8000 individuals. About 500 of these did not exist in the Museum of the Jardin des Plantes, and fully 300 were altogether new to science. In his investigations into the nervous systems of insects, he discovered that they possessed a complete nervous system; and he confirmed the general result obtained by Lyonnet and Strauss-Durckheim, that the nervous organism in in

sects is fully as complicated, if not more so, as in the largest animals, such as the elephant.

In concluding this chapter, our author is led to make the important remark, that the animal kingdom does not present one sole and progressive mode of development. On the contrary, from the very beginning of creation, there must have been simultaneously present the four fundamental groups which at the present hour include the entire mass of created animals; for we find that the Vertebrata, Articulata, Mollusca, and Radiata, are buried side by side in the ancient fossil beds of the earlier world. Even more than this, the three inferior divisions possessed at that remote period representatives of almost all existing classes; and if it is otherwise in respect to the Vetebrata-if reptiles, birds, and mammals are wanting in these primative faunas, a simple explanation of their absence would be furnished by the supposition, that the external conditions were incompatible with their mode

of life.

In their voyage from Jardini to Catania, the sight and sound of Mount Etna, constantly in their view, inclined our naturalists to attempt its ascent. The ascent of Vesuvius is a mere walk-that of Stomboli, a fatiguing excursion-and that of Etna, an arduous journey, not without danger. Catania, which they had now reached, though twenty-five miles distant from the great crater, is the direct product of the volcano. It stands within four beds of lava. Its houses are built, and its streets paved with lava. Its harbors have been filled up with the liquid fire, its gardens consumed, its walls overturned, and whole district buried under the burning

torrent.

Though Mount Etna rises in a pyramidal shape to nearly 11,000 feet, yet, owing to its base measuring from thirty to forty miles in circuit, it appears slightly elevated above the horizon. In the ascent of the mountain, which occupies forty-eight hours, the traveler is twice exposed to a variation of temperature of at least 72°, and a variation of pressure of 7517 pounds.

Leaving Catania at daybreak, they crossed the cultivated zone by a carriageroad, treading upon a bed of volcanic cinders, now pulverized by time, and bearing crops of grain, cherry, orange, and pomegranate orchards, and adorned with lovely

villages and charming country-houses, built of lava and cemented with pozzolane, and sometimes resting on the very verge of an ancient crater. Amid this wealth and beauty we encounter huge black dykes of lava, the witnesses of past and the forecast shadows of future desolation. Behind the houses of Nicolosi, we see rising the double summit of Monti-Rossi, so called from the dark red color of its scoriæ. In 1669, this crater buried under a shower of ashes the neighboring country, and threatened Catania with destruction, though twelve miles distant from it. It consists of two cones close to each other, and nearly 1000 feet high. At Nicolosi the travelers were received by Dr. Mario Gemellaro, one of three brothers who had devoted their lives to the study of Etna. In 1804 they built and furnished a cottage for the reception of travelers. Two years afterwards it was destroyed, but soon replaced; and the new building was, in 1811, thrown down by an earthquake. With a subscription obtained through Lord Forbes, the commander of the English troops, a substantial house, the Casa Inglese, was erected, which the volcano, more merciful than man, has still spared. The herdsmen of Mount Etna, however, more than once stole the furniture; and after it had been replaced, the Austrian officers, garrisoned at Catania, broke open the door in 1820, and burnt the furniture as firewood. After passing through dilapidated forests, and amid herds of cattle, they saw above them, like petrified torrents, the enormous lava beds of the Boccarelle del Fuoco, the twin craters, which in 1766 destroyed more than a million of oaks in the forest. At the Casa del Bocco they rested, and then entered the desert region. At the foot of Montagnuola, one of the largest secondary cones of the volcano, they saw the glaciers of Catania, and on account of the cold, they were obliged to climb on foot to the Casa Inglese, where they slept during the night. At two hours after midnight they resumed the ascent, and, on reaching the crater, stood motionless in the contemplation of the spectacle before them.

Beneath them yawned the great crater a deep and irregular valley bristling with blocks of blue, green, and white lava, and variegated with lines of curling vapor, issuing from a thousand vents, and suffocating the bystanders with their acid emanations. From the highest point,

which they soon reached, the whole of Sicily lay spread out before them-a scene which it is impossible to describe. The rising sun added to its grandeur; the gigantic shadow of Etna reached across the entire island to the remotest horizon, and gradually shortened as the sun rose above the Ionian Sea.

aid of some friendly cavalier, is necessary. The Basques or Spanish women are generally daring swimmers, and would often bring up a handful of gravel from a depth of ten feet.

About a mile from Biarritz is the Chambre d' Amour, a semi-circular hollow in the middle of inaccessible cliffs, to which the tide has sometimes penetrated. It is said to have been the rendezvous of two lovers, to whom it had often served as a trysting place, which the ocean had long respected. One day, however, a violent north-west wind raised the sea above its level; and on the following day, a fisherman, who penetrated into the cave found the bodies of the lovers clasped in each other's arms.

After a parting look of the valley of the crater, the guides took them to the brink of the crater, which, in 1842, threw its lava into the Val deľ Bove. The scene was strange and terrific. Eddies of fiery red smoke issued from a large vent. Deafening and whistling noises followed; and thousands of crossing and re-crossing streams of smoke, whose hydrochloric acid vapors, irritating their bronchial tubes, forced them to a quick retreat. From Having ascertained that there were few the Casa they descended to obtain a view marine animals at Biarritz, our author conof the Val del Bove, a most arduous jour- tented himself with making a large collecney, in which they reached the Torre del tion of fossils, and subsequently went to Filosopho, the supposed habitation of the Basque village of Guettary, six miles Empedocles. From hence they saw the from St. Jean de Luz. At Guettary he magnificent Val del Bove, six miles long found Polyophthalmians and Hermellas and three broad, inclosed by perpendicu- different from those in Sicily. The Herlar walls of lava older than the human mellas, which are tubicolous annelids, live race, and often rising to more than a thou- in little hillocks of sand, pierced by an insand feet from their base. After suffer-finity of minute openings, like a thick ing from a hurricane which raised clouds of sand that stung their faces like needles, they forgot their fatigues at the hospitable and well-furnished table of their host, Signor Abate, who had provided every thing for the ascent.

Having been long desirous of studying the marine animals in the Bay of Biscay, where his friend, Alexander Brogniart, alone had preceded him, M. Quatrefages proceded to Bayonne early in June, 1847, furnished with the diaries and journals of his predecessor. After witnessing a raging storm at the mouth of the Adour, our author visited the village of Biarritz, which he describes as "the very realization of some lovely and picturesque scene in an opera." It is now a fashionable watering-place. The Port Vieux, resembling an artificial basin, is perfectly adapted for bathing, and there the patriarchal customs of the place are still in force. Men and women, in suitable attire, swim and dive in the same pool, carrying on conversations and flirtations with each other, as at a party or on the promenade. It is an object of female ambition to reach the line thrown across the entrance of the harbor: and, in order to accomplish this, a swimming-belt, a pair of gourds, or the

piece of honeycomb. The bodies of these curious creatures, about two inches long, have a bifurcated head bearing a double bright golden-colored crown of strong, sharp, serrated silken threads. These crowns are the two sides of a solid door, or rather a true portcullis, which closes hermetically the entrance of their habitation. On the least alarm, the annelid darts with the rapidity of lightning into its house of sand. From the margin of the opening on its head issue about sixty violet filaments, like minute serpents, with which they seize their prey, and pick up, for the construction of their tubes, the grains of quartz or limestone, which are cemented together by a sort of mucus supplied by the animal. The feet of the Hermellas are bundles of cutting and serrateed lances, issuing from little projections on the sides of their body. Cirrhi, bent like sickles, are placed on the back, and are the branchia, which are distributed over every ring, instead of being united, as in other animals, at the head like the petals of a flower. The interior organization of the Hermellas is equally singular. Through the whole length of its abdomen, the muscles, vessels, and nerves are all double, and the two halves

are only kept together by the skin and a single digestive canal.

In studying the annelids, our author discovered many other phenomena equally remarkable. In this group there is an infinite variability of characters, which in other cases are constant. Their organs of motion and circulation vary remarkably in the different species. The respiratory system is sometimes enormously developed, and in other cases completely wanting. Even the nervous system is singularly variable, in the tubicolous annelids, many intermediate forms existing between the two extremes of develop

ment.

of fleshy cirrhi protect the delicate organ of vision. Grube, Krohn, and Will have detected the same organization in the other genera of the acephalous Molluscs, and in the Spondyli, Tellinæ, Pinnæ, Circæ, Pectunculi, etc.

As in other annelids, the body of the Polyophthalmians is formed of a series of similar rings joined piece by piece. A number may be killed or affected by gangrene without the rest suffering. Each is a complete animal, having a life of its own; so that the entire body is a colony, with the head as its chief. Organs of sensation, therefore, are alone wanting to make each ring a complete animal. This singular independence of the different portions of the same animal, and the diffusion of the faculties of perception through all parts of the nervous system, exists in insects "whose organic complication exceeds in many respects even that of man himself." Hence we see how the study of the lower animals leads us to ideas different from those which can be deduced from the exclusive study of the higher animals.

Among the annelids, the Polyophthalmians exhibit the most Proteus-like metamorphoses. It has long been questioned whether or not distinct organs of sense, more especially eyes, existed in the Mollusca, Articulata, and Radiata. Ehrenberg had found in the Amphicora certain colored points, which he regarded as two eyes, at the end of its tail, like those upon its head.* In the allied animals, M. Quatrefages found these colored points strangely multiplied, and could hardly From St. Jean de Luz our author went believe in such a profusion of eyes. He to St. Sebastian, the capital of Guipiscoa. saw, notwithstanding, the tail going first, It stands at the foot of Mont Orgullo, and exploring the objects without touching forms an irregular square, of less than them, and avoiding obstacles as if seen 120,000 yards in area, and accommodatwith eyes. Still he could not discover ing 9000 inhabitants. Reduced to ashes either a lens or a retina. At length, how- in 1813, the town is almost wholly new, ever, he found both in the Polyophthal- with the exception of its two churches, mians; and here he saw the fable of and a few houses near them. After a Argus realized. When at rest, this is a long history of the Basques, and their yellow, cylindrical, little worm, an inch manners and customs, M. Quatrefages long, with two rows of seta which serve proceeds to give an account of his zooas feet, with which, and the contractions logical researches, which were limited of its body, it moves with incredible ra- chiefly to the Teredo, an acephalous Molpidity, swimming in water by means of lusc of the same class as the Oyster and two large ciliated structures which act Mussel, and yet at first sight without any like paddle-wheels. It has on its head resemblance to them. When removed from three eyes, each of which has two or its tube it is a gray worm, sometimes a three large crystalline lenses; and on foot long, and half an inch in diameter, each side of the rings of its body there with a rounded head and bifurcated tail. is a red point, receiving a nerve, penetrat- The head consists of two immovable small ing a mass of pigment which incloses a valves; the mantle envelops all the viscespherical lens. The same facts have been ra, and then divides into two tubes, which observed in the Pecten, (the Pilgrim's the animal contracts or extends at will. Shell;) and our author has discovered One of the tubes introduces the aerated in the eyes in the mantle of a Mollusc water, and carries the food to its mouth, almost all the parts which are present in while the other, in removing the exhaustthe eyes of a mammal, even the eye- ed water, collects the residue of digestion. lashes and eye-brows, which in the form Notwithstanding its delicate and fragile shell, the Teredo is one of the most formidable enemies of man. In a few weeks it will excavate so completely large open

*By an eye is meant a crystalline lens and a retina.

ings in the thickest planks and piles of oak or pine, as to destroy ships at sea; and early in the last century one half of Holland was nearly engulfed, from the piles which supported her dykes having been destroyed by Teredos.

It has been supposed that wood, steeped in corrosive sublimate, resists the attacks of the Teredo; but as this mode can not be generally applied, our author proceeds to describe a process by which the animal may be destroyed within a given space. The Teredos are of different sexes. The female lays her eggs within the folds of her respiratory organ, and here the young are born, and live for a certain time. When they undergo their last metamorphosis they quit their mother's branchiæ, and fixing themselves upon the nearest piece of wood, they construct their galleries, and are beyond the reach of attack. We must, therefore, destroy them before this period, or rather prevent their birth-an object which may be effected by dissolving a little salt of mercury, lead, or copper, in the water which their mothers respire.

In all animals hitherto examined, the ovæ of the female are fertilized by minute organic particles, moving with extreme rapidity, not living animalcules, but having a certain share of vitality to enable them to move somewhat like the tail of a lizard separated from its body. The males emit this at random; and, existing in the aqueous mass, some of it finds its way into the branchiæ of the females, and vivifies the eggs which are there. Our author has found that a twenty millionth part of a mercurial salt, thrown into the water, would in two hours deprive the fluid of its vivifying power, and the ten millionth part in forty minutes. We have, therefore, only to throw a few handfuls of the poisonous salts into the surrounding water, in order to preserve the submerged wood in our marine docks or wharfs.

In the continuation of his eighth chapter, our author enters upon the great questions which are suggested by the study of Embryology. He inquires whence comes the germ of the new being? what are the laws which preside over its development? what is the probable part played by the two elements which almost always concur in the reproduction of the species? and he tells us that the same laws are applicable to plants and animals. A plant is multiplied by seeds, buds, bul

bils, cuttings, etc.; and animals present to us analogous facts. Cut to pieces a Hydra, and in a few days each piece is a complete individual. This is reproduction by cuttings. The same Hydra will lay eggs with a solid shell-that is, it will produce true animal seeds; while, at another time, it will give off buds that grow into a young Hydra, which adheres like a parasite to its parent, and after seeking food on its own account, and attaining sufficient size, separates itself, and leads an independent existence. In certain plants there is a structure called the bulbil, intermediate between a seed and a bud. Though resembling a bud, it must, like the seed, be separated from the plant before it gives origin to a new individual. On the shell of the Synhydras there are protuberances, kept together by a horny net-work. This is the polypary, or common body, containing the entire colony. From this polypary buds are given off, which become Hydras, without leaving their place of birth, and therefore comport themselves like the branches of a tree. From the same polypary are ejected eggs, which, like the seed, are developed, and propagate the species after they are separated from the parent plant. A certain number of individuals generate deciduous buds, or true bulbils, which, without arms or mouths, only propagate their species, and are fed by their neighbors.

As every living being proceeds from a preexisting germ, it has been a difficult problem to determine the origin, nature, and development of these germs. The doctrine generally received (that of epigenesis or successive formations) is, that buds, bulbils, eggs, or seeds are produced from a preexisting individual-that some have the vital activity necessary for their development, in which case there is neither father nor mother, while others require the special agency of one sex to vivify the mature germ secreted by the other.

Believing that the faunas of different regions correspond to the nature of the geological strata, our author visited La Rochelle, nearly half-way between Nantes and Bordeaux, with the view of confirming this general fact. He had found that limestones are less rich in marine animals than schists and granites; algae and fuci, which can not fix themselves securely to limestone, adhere firmly to granite; and

« PreviousContinue »