injured health and depressed spirits, a gloomy, regretful man; it is sad to see the heir so fit for his earthly inheritance taken from it, that it may be possessed by one who deserves it so little; but we are not left to indulge this sadness under the dreary conviction that the triumph of evil over good is the common law and lot of Vanity Fair. Miss Yonge knows better than that. By her skillful treatment of the lighter parts of the story, she prevents the mind from being oppressed by its pathos, and so well works out her hidden meaning, without giving it formal expression, that she makes us feel there is something better than earthly happiness and success, for the sake of which our latent sense of heroism teaches us at last to be content that Guy should die. The same high lesson is brought before us in the wild-dream romance of Zanoni. George Eliot gives us heathen tragedy under a Christian form; Bulwer gives us Christian tragedy under a heathen form, wrapped up in a jargon of art, philosophy, and alchemy. He represents Zanoni, the Pythagorean seer, who has attained the secret of boundless wealth and knowledge, life and youth, constrain ed by his love, and by the pressure of danger and evil on those he loves, to yield his glorious gifts one by one, to be subject to the malignant powers which he had formerly commanded, beaten backward, step by step, from intercourse with bright ethereal spirits to the weakness and sorrow of mortal life, until he has to yield that life itself to save his wife and child; yet, in that last hour of defeat, recognizing the true secret of victory, and asserting his trust and triumph over earth-evils and spirit-foes. "Did he mean all that by shaking his head?" says Sheridan, in The Critic. So our English novelists may say: "Do we mean all this by our amusing stories? Do we inculcate these grand lessons, and do our readers understand us?" That depends-considering that in novels bad lessons are much more often taught than good ones, we should be glad to think that readers in general did not understand them. As a rule, novels are read for mere amusement, all action of the moral judgment being suspended for the time; and in that fact is to be found the greatest evil of a habit of novel-reading. Fiction has two different effects; it is a stim ulant and a sedative. It can stimulate the fancy for good or evil, and it can soothe the mind to forgetfulness of good or evil-to forgetfulness of care or worry, also to forgetfulness of work, of duty, of the claims and responsibilities of real life : and though it is customary to condemn fiction chiefly as a stimulant, we think that, in the present day, its sedative effects are far more pernicious. It is injuring us less by that which it does, than by that which it prevents us from doing. If it raises unhealthy longings in those who, by its aid, mistake fancy for truth, it quiets healthy aspirations by thrusting aside real life, and offering us a make-believe in its stead. It teaches us to take interest in, to feel with, grieve with, rejoice with, that which is not reality, that of which the great charm is, that it does not trouble us with the severe obligations of truth. Many a youth and man who would throw down in disgust the novels which might tend to stimulate his evil passions, wastes over them, without scruple, the time and thought and energy which should be spent in study or in work. Fiction, at present, ministers less to remembrance of evil than to forgetfulness of good; and in this way our swarming serials are doing us a great illservice. Their power as stimulants is much lessened by the month's interval that separates the consecutive scenes of the story; but their power as sedatives, to indispose us for steady thought or hard work, is much increased by their constant recurrence and wide circulation, for thus they catch us at unwary moments, and waste far more time and thought than would ever be deliberately given to novels in a more condensed form. What shall we say to the habitual novel-reader? It is true that God has given us mental stimulants and sedatives to meet the wear and tear of daily life; and that first among those which refresh without after-exhaustion, the pleasures of imagination take their place. In the glory of nature, the graces of art, the charm of poetry, the magic word-painting which we call "fiction," God has supplied us with the means of temporary escape from the pressure of reality, when business, or care, or pain, or sorrow, weighs too heav ily upon us. We do not say that tonics would not often better meet the need; nevertheless, in many cases of earthly weakness, stimulants and sedatives are Each allowed and provided. It would be hard | which inundates us on all sides. It is useless to place around the young restrictions which are not sanctioned by the tone and temper of the age; and we might as well bar our doors against the spring-tide as against the torrent of stories, serials, and green and yellow literature, that age of departing innocence and ad- From Chambers's Journal. COMPARATIVE THE air we breathe, subtile and invisible as it is, contains elements which have the property of separating themselves from each other, and of entering into composition with living creatures, according to the proportion required for the carrying on of their vital functions. Every thing that has life, whether it be vegetable or animal, by the very use of its organs, causes a waste of their substance which requires constant renewal. In an imals, the waste is denoted by an excess of carbon, which must be expelled from the system, and by a diminution of oxygen, a fresh supply of which must be constantly kept up. This is accomplished by means of a law according to which gases of different densities, that are not dispos ed to unite chemically, have a strong tendency to mutual admixture. If a bladder of hydrogen be placed in a vessel of carbonic acid, a certain quantity of hydrogen will pass out of the bladder, and a still larger amount of carbonic acid will enter therein. This interchange of gases through a thin membranous substance goes on the more rapidly as there is a greater difference of density between the gases. All animals are supplied with such a membranous substance in one or more parts of their body, through which carbonic acid may be expelled and oxygen imbibed, for the maintenance of the bal ance of life. Indeed, even in the vegetable world, there is a constant interchange of gases going on; the leaves of plants giving off oxygen in the sun-light, and absorbing carbonic acid from the atmosphere, carbon being an important element of food for the plant. There have been counted as many as seven millions of leaves on an oak tree, each leaf having hundreds of thousands of pores, through which pass the gases for the maintenance of vegetable life. The fresh-water algae in our ponds absorb carbon from the water, and by so doing, purify it from decayed matter; hence fishes are most healthy in those ponds where there are aquatic plants. RESPIRATION. Though all animals require means for parting with carbon, and for obtaining a fresh supply of oxygen, yet the extent of their wants in this respect varies greatly in degree. According to the temperature of the body, and the activity of their habits, will be the generation of carbonic acid requiring expulsion, and the demand for a renewal of oxygen; also, this will be affected by the widely varied habitat of animated creatures, some living in water, and some on land, while some are amphibious, and others have wings for flight. These differences have necessitated an extensive variety in the breathing mechanism, so that, whatever its habits, and wherever its home, every living being may be able to obtain that amount of oxygen which is necessary for its life, and to get rid of the noxious surplus of carbon. Deeply interesting is it to notice the varied structure of the respiratory organs in the different classes of animals, and their marvelous adaptation to the wants of each, exemplifying as they do the skill of the Great Creator, and the beautiful harmony of all his laws. Those creatures which live in the water are cold, and often have no red corpuscles in the blood; especially is this the case with mollusks, which lead so inactive a life; therefore, they do not require a large supply of oxygen to their system, and find a sufficient medium of respiration in the water which surrounds them, and which contains enough oxygen for the purpose. The lowest in the scale of animated beings that has a special provision for aërating the system, is the class to which belong the star-fish, medusa, etc., from the digestive organs of which are communications with the outer disk of the fish, where cilia or small hairs are attached, that convey to the animal a fresh supply of oxygen through the medium of the water. The common sea urchin, and such animals as are covered with a hard shell through which no gases can pass, are provided with a membrane between the shell and the viscera, that contains minute ramifications from the body, and to which water is admitted through openings in the shell for the purpose of respiration. In the ordinary bivalves, as the oyster, muscle, etc., there are, near the mouth of the shell, innumerable ciliæ, on the part commonly called the beard, which are con stantly in motion, and which edge four ribbon-like folds containing the blood to be exposed to the surrounding water; likewise the shells of these mollusks are provided with not less than two apertures, one for drawing in, and the other for expelling the water, while each opening is furnished with a long tube or siphon, through which water may be obtained or ejected when the animal is buried in the sand. In the class containing crabs and lobsters, the mode of respiration is somewhat similar, but confined to one organ, and contained in a separate cavity, where, through two orifices, the water finds in gress and egress, being propelled by a valve which by its movements occasions a constant flow of water over the internal gills. In the crustacea adapted to live on land, the gills require additional care to keep them moist for the purpose of respiration; hence, the orifices of the bronchial cavity are reduced in size, that evaporation may take place slowly; also, the membrane lining the bronchial cavity of land-crabs is folded in such a manner as to contain a large amount of fluid; besides this, land-crabs by instinct always frequent a damp situation. that remain at the bottom of the water, is not necessarily connected with the respiratory organs, excepting in the case of those fresh-water fishes that have a windpipe for the passage of air, and which sometimes come to the surface to breathe. Of insects it may be remarked, that they do not obtain air through the mouth, which is therefore to them no organ of sound, but one for biting and taking food. Their rapid motion requires that their system should be well oxygenized; hence, according to the nature and habits of the insect, air is admitted to the body through several distinct apertures, and carried by a minutely distributed system of tubes, which ramify through even the smallest organs, to all the tissues, whilst at certain parts they dilate into little bags of various degrees of size. In those insects which sustain long flight, as the bee, these airbags are most developed, perhaps to render their bodies lighter, and perhaps to supply them with more air when some of the external apertures are closed. The wings of insects are covered with very minute tubes, which are connected with their system of respiration, and which become very much distended during flight. There is great variety in the breathing mechanism as regards the larva of insects. In the larva of the gnat, the last segment of the abdomen is prolonged into a tube, the mouth of which remains above the water while the body is immersed. Sometimes the air-tube is fringed with bristles, which entangle a bubble of air sufficient to support respiration, while the little creature descends to the very bottom of the water, the large vessels connected with this tube conveying the air over all the body. In spiders, as in scorpions, the breathing-pores do not open into a system of air-tubes, as is generally the case with insects, but into distinct sacs disposed along the sides of the abdomen, and to which the air has immediate access: these sacs, having the rudiments of minute cells, are somewhat like lungs, for the blood of the insect is brought to them, and duly oxygenized. Fishes, again, living as they do wholly in the water, have a different arrangement of the breathing mechanism. Though cold-blooded, and obtaining from the water as much oxygen as they need, yet their rapid movements indicate a fuller aëration of the system than in the species we have already noticed; indeed, so aërated is it, that their blood is furnished with red corpuscles which can convey oxygen and carbonic acid. The gills, connected with the cavity of the mouth, and covered by a bony lid, are disposed in laminae fringed like the plume of a feather, which must be kept moist, or else the transfusion of gases can not go on, The lungs of the several orders of repand hence fishes taken out of the water, tiles are, for the most part, capacious sacs, not being able to breathe, soon die. The which, in those of the class to which the gills being constantly and thoroughly bath- turtle and tortoise belong, have an inciped by the current of water over them, oxy-ient subdivision. In the lung of the frog, gen is taken up into the system, and the the lower part is a mere sac, while at blood purified to the extent required. The the upper part many smaller sacs are air-bladder, which is wanting in those fishes developed, by which arrangement the surface is increased to a great extent. | system renders the body of a bird light in Some reptiles, and among them the frog, proportion to its size, and this is materialhaving no diaphragm, are obliged to fill Îy increased by the heat and rarefaction their lungs by a process which resembles of the air passing through it. Of all aniswallowing, as may be observed from the mals, birds require the most constant renever-ceasing movement of the under part newal of fresh air, and an atmosphere of of its jaw; and thus the most effectual the greatest purity: air which can be mode of suffocating a frog is by holding breathed by inammals is sometimes so its mouth open for a short time, so that it charged with carbonic acid as to be fatal can no longer respire. In serpents, the to birds. breathing apparatus consists of a long cylindrical sac, furnished in part with minute air cells that communicate with each other, and with the general cavity. The capacity of this sac, and the mobility of their ribs, together with their muscu larity, enable them to take in a considera ble quantity of air. The hissing noise by which serpents sometimes alarm their prey, is caused by the long-continued expulsion of air after the lungs have been fully inflated. As regards water-serpents, the large volume of air contained in the body tends to render them buoyant, and also supplies them during their immersion. In the saurian reptiles, the lungs show increasing devolopment, and, as they advance up to the crocodile, become more subdivided into cells; also in these monsters the lungs are confined to the thoracic region, and some indications are to be seen of a diaphragm. Yet alligators and croco diles are feeble in respiration compared to their size, and, being cold-blooded animals, are very sluggish; they do not seem to suffer much inconvenience when their breathing is for a time suspended. The respiring mechanism of birds approaches nearer to that of mammals, though having a great analogy to the organs of winged insects. Their lungs are placed in equal proportions on both sides of the chest, whereby the body is nicely balanced during flight; also, they are much subdivided into small cells, present ing quite a spongy appearance. But besides the lungs in the chest, they have likewise air-sacs connected with them in the neck, the abdomen, and extremities; the bones, too, are hollow, and their cavities communicate with the lungs. The distension of the air-cells tends to keep the wings outstretched, as is shown in dead birds that have been forcibly inflated, and their wings thereby expanded; and thus, in those birds which take long flights, their muscular action is economized by their increased power of respiration. The diffusion of so much air through the Mammals-the class to which we ourselves belong are furnished with a breathing apparatus very complex and extensive, and this on a scale that varies according to the food and habits of the animal. Provision is made for the free removal of carbon, and for the renewal of a large supply of oxygen, without impeding motion or action. The lungs, divided and placed on each side of the chest, are kept in active play by the constant heaving up and down of the diaphragm, by which air is brought into the internal reservoir, and after having served its purpose, is again pumped forth. It is calcu lated that the bulk of air drawn into the human lungs and thrown out again, is about eighteen pints a minute, one thousand pints an hour, and three thousand gallons a day; but as we never entirely empty our lungs by an expiration of the breath, there is always a considerable quantity of air remaining within. Linde nau asserts that, such is the vast area of our lungs, that the amount of surface they present to the blood is not less than twenty-six hundred and forty-two square feet; for, besides that the tubes of the lungs branch into multitudes of vessels fine as hair, there are thousands of vesicles clustered around the extremity of each; and so exceedingly thin is the membrane covering them, that they offer no obstacle to the free interchange of carbon and oxygen. Over the whole of this extensive surface of the lungs is spread a net-work of minute vessels filled with blood, undergoing constant purification; the venous blood, that has gathered up impurity from all parts of the system, yields its carbon to the lungs, and is by them duly oxygenated. After this process, the air, impregnated by carbon, is expelled from the lungs by the effort of breathing, and discharged through the windpipe; it is of course impure, and should not be again inhaled. Health demands a constant supply of fresh atmospheric air, for otherwise the carbon of the system is not properly |