to read it.

7. Are you right to buy a velvet coat? 8. I am right to buy one. 9. Does your little girl want to sleep? 10. Yes, Sir, she wants to sleep, she is tired. 11. Are you afraid of falling? 12. I am not afraid of falling. 13. Has the gardener time to work in the fields? 14. He has no wish to work in the fields. 15. Are your fields as large as mine? 16. They are larger than yours. 17. Are you ashamed to walk? 18. I am not ashamed to walk, but I am ashamed to dance. 19. How old is your son? 20. He is sixteen. 21. Is it the second of March or the fifth of June? 22. It is the 28th of July. 23. Is it noon? 21. No, Sir, it is not yet twelve, it is only half-past eleven. 25. It is early yet.

RECREATIVE NATURAL HISTORY.
THE SWALLOW.

In our present paper on the swallow we must limit our remarks to the four British species: the Chimney Swallow, House Martin, Sand Martin, and Swift. The Alpine, or white-breasted swift, the spine-tailed swallow, and the purple martin, cannot be considered British birds, though they may have been seen in our island. Scientifically speaking, the swifts and swallows are included in a group to which the name Hirundonida has been given, from the Latin hirundo, a swallow. This group is subdivided into two lesser groups, under one of which all the swifts are classed, while all the various kinds of swallows and martins are placed in the other. Swifts are distinguished from swallows by the extreme length of the first two primary feathers of the wing.

The Chimney Swallow is one of the earliest arrivals, coming from Africa over the English Channel about the middle of April. Of course the birds do not travel direct from Africa in one journey. Italy, Spain, and France become so many stages on the road, where food is picked up, and some rest obtained. There appears to be a little self-will or caprice about some of the birds, a few having been known to show themselves in January, and others waiting till May.

Every one seems glad when the first swallow flits across the village green, but we sober English have never kept a "swallow holiday" on the 15th of April, which is, in some parts of Europe, called "swallow day." In ancient Greece the children might well clap their tiny hands when the birds of spring appeared; a holiday being then given to little boys and girls. They danced in the market-places, wove garlands of the early flowers, and shouted in the luxury of childish joy. That was a capital plan for making children love the birds.

Why do we call it chimney swallow ? Simply from its tendency to build in hollow places, such as old mine-shafts, disused wells, or chimneys. Some of these birds show very odd tastes in selecting a family home. A table drawer had been left open in a room seldom occupied, and, a window-pane being broken, a pair of these swallows appropriated one corner of the drawer for their nest. When the human owner wished to use the table, most emphatic were the remonstrances of the birds. Depart they would not; the hen fluttered her wings, screamed angrily, and plainly intimated that the corner had become her property by right of occupation. This bird logic prevailed; the little family was brought up in safety, and all parties were satisfied.

The chimney swallow is easily known by its deeply forked tail, the ruddy hue on its throat, and its lightish tinted breast. The rapid movements of the bird-its sudden darts and turns, now up, now down, over the observer's head, and then skimming the ground in long, arrow-like flights-present a specimen of a living machine in beautiful and perfect action. But, notwithstanding this power of flight, the birds are sometimes completely exhausted by their journeys across the sea. They can battle for a long time with the mere force of a tempest, but when the blast is both cold and strong, the winged voyagers are almost paralysed. A whole army of swallows will then crowd the rigging of some lonely ship, clinging for hours to ropes and spars, until recovered strength again enables them to obey the "forward" impulse. No wonder if these beings of summer climes sometimes marvel at the rough treatment received in our ruder latitudes. A cutting "north-easter" is no smiling reception for a creature which has been basking for months in the sun of Egypt. The result may amaze the swallows, but human philosophy can explain it all. They perish by thousands in such years. On one bitter spring day, a gentleman

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picked up in the course of his morning's walk ninety-two chimney swallows, not dead, but benumbed by the cold. Being placed in a warm hamper, they all recovered, and flew off the next day. On another occasion numbers were found on the window-sills of a country house, heaped on each other five or six deep. Instinct had clearly led them to seek aid from man. Some may naturally ask, why do the swallows so eagerly rush from the warm regions of the south to battle with the storms of the north? We cannot answer the question; guessing might, of course, be carried to a great extent, but guessing on such subjects is trifling. That there is some wise purpose in the habit we may be sure, or it would not exist. Another remarkable feature about chimney swallows is their courage. Look at these birds fighting with a hawk, and then say whether they are cowards. Of course they suffer for their daring? Not in the least; the hawk gets the worst of it, and retreats in a fury from the inglorious contest. What can the hawk do? He is a brave fellow, but the swallows are too quick for him, darting down on his back, and up again with a speed which baffles the clutch of his talons. He resembles a heavy seventy-four man-of-war surrounded by a fleet of steam gun. boats; strength is beaten by speed.

The chimney swallow does not come to the British Isles for a holiday, that is certain, but for downright hard work. The building of a house, and the bringing up of two families in one short season, are enough to tax the energies of the most enterprising bird. The parents are so hard pushed for time that the first family often receives warning to quit before its education is quite complete. But the little things soon manage to provide their own food without the aid of the mother bird. The second family sometimes fares the worst, being forced to join in the great autumnal migration as soon as they are able to fly. The assembling of these birds is a well-known sight. How closely they crowd on the house-tops, trees, and railway wires. How silently they sit for awhile, as if reflecting on past errors, or speculating on future mishaps. Then what a sudden burst of chattering is there, as if every bird were determined to force his own particular hobby on his neighbour.

Some naturalists have suggested that a few of these birds remain here in a sleeping state during the winter, and reappear, lean and hungry, in the spring. Others laugh at this notion as "absurd," and pooh-pooh the opinion altogether. We venture, however, to agree with those who refuse to believe in the swallow's winter sleep. If some of the birds remain behind, they probably perish from want of insect food, except in those rare winters when frost is almost unknown.

The House Martin is easily distinguished by its snowy breast, and noted for the trusting confidence in which it builds its nest above our doors and against our houses. It arrives here somewhat later than the chimney swallow, and is a surer prophet of sunny skies. In this light the ancient poets regarded the martin, singing its praises as the loved herald of flowery meads and laughing hours. Have swallows a good memory? Do the martins really find their way back to the parent nest over African deserts, ocean waves, and Spanish mountains by memory? If so, the organ of locality must be large in their little brains. But then we are cautioned against applying phrenology to the heads of birds, and we therefore pause in the midst of a tempting speculation. The same nest is often used year after year by surviving members of a family, and sometimes a little bird village of nests is formed by the labours of several generations. How do the little builders make the materials of the nest so adhesive that the work adheres not only to a brick wall but to a smooth window-pane? Here, again, the answer comes, "we know not." See, too, how careful the birds are to build up little by little, allowing each day's work to harden before a fresh layer is added. All this looks very much like the skill of Devonshire workmen when building the "cob-wall"-a composition of mud and chopped straw, used for the upper part of the walls of barns, and even cottages, in some parts of that county. We call this instinct in the birds, but we really know nothing of the matter.

Our pretty martin is not always very honest in its notions, even taking possession of a neighbour's house, and then fighting desperately in defence of the wrong. "Just like human beings," some satirists will, perhaps, say. Honesty, however, is found in the long run to be the best policy, even among martins; a series of battles, the loss of pretty

COMPARATIVE ANATOMY.-VII.

HELMINTHOZOA.

ALL the animals of which we have hitherto treated have been inhabitants of the water. Those which form the subject of the present lesson have a very strange habitat. They, for the most part, take up their abode in the interior of other animals, being found in the alimentary canal when they have become completely developed, but occupying all the several soft structures of the bodies of the higher animals when in an immature condition. Some writers have been disposed to treat of them not as a division or class in the animal kingdom, but as a peculiar fauna or assemblage of animals occupying a peculiar locality. Just as we might describe the animals of Europe, dividing that continent into natural districts, and stating what kinds of animals are confined to the Alpine region, what kinds are

enigmas. Those who believe that animals were introduced to the globe, created, or derived from one another in the order of their development or position in the scale of Nature-the simplest animals coming first in time-are at a loss to account for the appearance of these animals. Standing next above the Echinodermata, they should precede all the higher grades of animals, and yet their very existence and history implies the presence of animals of a higher grade, who act towards them as hosts. Again, these animals offer strange exceptions to the harmony of Nature. It is true that all animated Nature is a battle-field, in which species carry on their unrelenting hostilities towards one another; but this very strife results in an admirable harmony, there being a place for each species, while each is held in check by the others. The sickly and wretched make way for the robust, and strong, and joyous. On the other hand, that an otherwise strong and robust animal should

partial to the plains, etc.: so would these authors consider the | bodies of the higher animals as the continents in which these strange creatures have their range; and state how some are prone to take up their abode in the liver, some are lodged in the brain, and others find their home in the muscles. This, however, is certainly not a scientific view of the subject, and the facts of the case do not compel us to adopt it. For though there is doubtless much diversity in the structure of these animals, and they show relationships to two if not more classes, yet those included under the class we name Helminthozoa are so far distinguished as to make up a definite class, which, however, does not quite run parallel with the class Entozoa, inasmuch as it includes some animals which never take up their abode in the interior of others. The class Entozoa was never a good designation, as many of these animals that are the most typical of their class, as intestinal worms, pass some of their stages of existence in water, etc., outside the bodies of animals. These creatures offer to the speculative faculties many

become the prey of internal parasites, which do not strike it down and put it at once out of its misery, but cause emaciation and slow and painful death, seems strange, when we consider that the whole of creation was fashioned to one design by a supreme and benevolent Being. These remarks are, of course, only offered to show how impossible it is for us to understand or account for all the works of the Infinite.

One of the best known and most typical forms of the lowest sub-class of Helminthozoa, is the common tapeworm, called Tania solium. The name Tania means a band, and is given because of the long, flat, strap-shaped character of the animal's body. The specific or trivial name, solium, meaning solitary, was given because it was at first imagined that only one of these animals were ever found in one person at once. This, however, has been proved to be a mistake.

This disgusting creature is found in the alimentary canal of It is often many feet or even yards in length. Its head is armed with two kinds of organs for effecting its adhesion to the

man.

sides of the intestines. It has a proboscis, and around this are two rows of hooks, which point backward, so that when the animal plunges its proboscis into the soft mucous coat it cannot be pulled away, and hence holds its position, notwithstanding the continued transmission of food and the constant motion of the alimentary canal by which it passes forward its contents. Besides these, four suckers are situated below the hooklets on the rounded head. An attenuated neck gradually enlarges as it proceeds downwards, and, at a little distance from the head, closely set and fine constrictions are observed, which become larger and more especially longer as we trace them downwards towards the tail-end. These constrictions become also more and more definite and deeper, dividing the animal into segments, which, being longer than wide and very flat, look like a series of oblong cards.

In each of these segments a complete set of reproductive organs, both male and female, are found, and each in course of time produces an immense brood of eggs. When this condition has been arrived at, the segment drops off and crawls about, making its escape from its host, and finally bursting from the increased growth of the contained eggs, it scatters an immense multitude of germs. At a first consideration, one would have thought that these germs, cast forth into the world, and dependent for development upon their admission to other hosts, would have but little chance of complete life; and this is no doubt true with regard to each single germ. In this case, however, Nature makes up by multitude for efficiency. If we consider that each tapeworm has many hundred segments or joints when found in the interior of man, and that these joints are continually renewed from above as they fall away, and that each segment contains thousands of ova which are cast into various situations-into garbage, water, etc.-it is not wonderful that some are taken into the interior of some suitable animal.

These animals, being constantly provided with digested food which has been elaborated by their hosts, do not need any food canal of their own to digest aliment, but absorb it when already dissolved through the walls of the body. In fact, their stomachs, so to speak, are external, and correspond to the skin of other animals. Running along each side of the animal is a narrow duct. Cross-branches unite the two ducts, one to each segment, and run across at the part farthest from the head. These two lateral canals were long considered as the alimentary system of the animal; but it was found that it had no opening forwardthat is, it was without a mouth-and although there is an opening at the other end of the body, yet it is now considered to be the atrial system corresponding to the water-vascular or ambulacral system which we have described in the Echinodermata.

The egg with its contained embryo being swallowed by some animal, the latter does not remain in the food canal and become developed into a tapeworm, as might have been supposed, but immediately that the coatings of the egg are dissolved away, the embryo, which is armed with six boring-hooks, makes its way through the walls of the alimentary canal, and traverses the body in any direction until it reaches some structure suited to it, and there it rests and becomes more fully developed. The development is commenced by the formation of a bladder which is proper to the animal, while the soft organ in which the parasite is lodged forms a self-defensive cyst around this of common (areolar) tissue. Thus the creature is snugly ensconced in a cavity, through the walls of which the liquids penetrate, and are absorbed by the bladder-like animal. By the aid of this nutriment fresh changes occur with the growth of the larva. Thus on one side of the interior of the bladder a round body grows and so projects into the cavity, and in this the head and neck of the future perfect worm are formed. On this head the circles of hooks and the suckers are developed, so that the examination of the larval form when at an advanced stage will enable the examiner to determine to which species the creature belongs. When this process is completed, the larva has reached a stage beyond which it cannot become more developed unless it changes its position, and this change of position is not an active but a passive one. Hence multitudes of these creatures probably die and become disintegrated without ever attaining the perfect form. Those, however, whose life-circuit becomes complete, are transferred to the stomach of a carnivorous animal by the flesh in which they are lodged being devoured. Thus the animal has two different hosts, one of which entertains it in the immature condition, and the other when it becomes perfect and sexually

capable of reproducing its species. Most of these cystoid animals, when in the cystoid or bladder-like state, inhabit the soft structure of herbivorous or grain-feeding animals, while when they arrive at the cestoid or tape-worm condition they are found in the carnivorous animals which feed upon their former hosts. It has been shown that the Cysticercus fasciolaris of the liver of a mouse becomes the Tania crassicollis (the thick-necked tapeworm) of the intestines of the cat, and the Cysticercus pisi formis (the pea-shaped bladder-tail) of the rabbit becomes the Taenia serrata (notched tapeworm) of the dog. In the case of the species we have been describing, the host of the larva is usually the pig, and the host of the adult worm is man. As might be expected, it is found that the Tania solium infects those most who are especially fond of ill-cooked sausages. In Germany this unfortunate taste for nearly raw pork has produced the most harmful results, not only by introducing this worm, but also another called Trichina spiralis, a worm of much higher organism, and belonging to an order to be referred to hereafter. When the flesh containing the encysted entozoa is being digested by the animal who has been unfortunate enough to swallow it, the digesting operation goes on not only so far as to liberate the creature, but also to dissolve away the bladder which encloses the head. Then the creature, like the liberated genius in the "Arabian Nights," begins to take revenge on its liberator for its long imprisonment. It fixes itself by its hooks and its suckers to the walls of the intestines, and its tail grows and becomes segmented as before described. As compared to the immense length and size of the chain of segments, the head is ridiculously small; and thus the simile of the genius, who, when liberated from his bottle, assumed such vast and formidable dimensions, is not inappropriate to the rapid development which follows the liberation of this worm from its cyst.

The effect upon the human system occasioned by a tapeworm is extremely distressing. The patient suffers not only from loss of appetite, emaciation, and lassitude, but the sympathetic nervous system is affected so as to produce convulsions and epilepsy. Distressing, however, as these effects are, they are not so fatal as are those produced by the presence of the immature form, because the adult worm is confined to the intestines, and is thus, so to speak, in a situation external to the body, while the larvae, as we have seen, penetrates into all parts of the body, and their presence is more or less injurious as they take up their abode in the more or less vital organs. If they find their way to a position under the skin or in the muscles, they are compara tively harmless; but if they penetrate the eye or the brain, they occasion pain and sometimes death.

In tracing the circle of life of the Tania, we find it runs through all the forms named, in the following order :1. The egg.

2. The embryo, actively travelling by a six-hooked boring apparatus.

3. The resting larva, consisting of a head enveloped in a terminal bladder.

4. Immature tapeworm liberated from its bladder. 5. Segmented and sexually mature tapeworm.

6. Free segment, called a proglottis, from its likeness to the tip of the tongue.

This creature belongs to the sub-class Anenterelmintha, which is distinguished from the sub-classes to which the other animals of the class belong, by having no alimentary canal of any kind. This animal, in common with all belonging to this sub-class, is entirely nourished by absorption, and for this reason we have taken the tapeworm as the type of an entozoon.

The animals of the sub-class Sterelmintha differ from these in having an alimentary canal channelled out in the substance of an otherwise solid body. Our best English writer on the Entozoa, Cobbold (whose books should be read by those who wish for a more intimate acquaintance with the class), takes the Distoma con junctum, which he found in the intestines of the American red fox, as a type of the sub-class. The animal belonging to this sub-class, with which we are unfortunately best acquainted, is the liver-fluke, which occasions the disease called the rod in sheep. This creature is found abundantly in the liver of sheep so affected. Sometimes as many as a thousand have been found in a single liver. The animal is of considerable size, measuring from to 1 inch in length, and about inch in breadth. It is flat, and shaped like a little sole. Its anterior extremity is extended into a nipple-shaped projection, at the end of which is the