for it is not constructed for the temporary purpose of rearing and concealing the young, but for the permanent abode of individuals of all ages.

Of mammalia that build social habitations the beaver is the most conspicuous; and, although many exaggerated accounts have been written of the operations of these animals, the fact remains that they are most skilful engineers. Mr. Wood describes the manner in which the beaver forms a dam.

'When the animal has fixed upon a tree which it believes to be suitable for its purpose, it begins by sitting upright, and with its chisel-like teeth cutting a bold groove completely round the trunk. It then widens the groove, and always makes it wide in exact proportion to its depth, so that when the tree is nearly cut through it looks something like the contracted portion of an hour-glass. When this stage has been reached, the beaver looks anxiously at the tree, and views it on every side, as if desirous of measuring the direction in which it is to fall. Having settled this question, it goes to the opposite side of the tree, and with two or three powerful bites cuts away the wood so that the tree becomes overbalanced, and falls to the ground. This point having been reached, the animal proceeds to cut up the fallen trunk into lengths, usually a yard or so in length, employing a similar method of severing the wood. In consequence of this mode of gnawing the timber, both ends of the logs are rounded and rather pointed.'

The next part of the task is to make these logs into a dam, so as to keep the water to the proper level. The logs are placed horizontally, and formed into a mass with earth and stones, so as to be sufficiently strong to resist the force of the stream. Instances of dams measuring two or three hundred yards in length, and ten or twelve feet in thickness are not uncommon. It is curious to observe that if the water rises with a strong current the dam is made in a convex shape, so as the better to resist the force of the water; but if the stream runs slowly, the dam is carried straight across the river.

'In places,' says Hearne, who has given an excellent account of the habits of this animal, which have been long frequented by beavers undisturbed, their dams, by frequent repairing, become a solid bank, capable of resisting a great force, both of water and ice; and as the willow, poplar, and birch generally take root and shoot up, they by degrees form a kind of regular planted hedge, which I have seen in some places so tall that birds have built their nests among the branches.'

The dome-shaped beaver-houses are built of the same materials as the dams, being proportioned in size to the number of inhabitants, there being generally four old ones, and six or seven young

ones.

ones.

Sometimes there are several divisions or apartments in a beaver-house, but they are not, as a rule, connected with each other except by water. Hearne says he once saw a large beaverhouse built in a small island that had near a dozen apartments under one roof, but with two or three exceptions, they had not communication with each other except by water. As there were beavers enough to inhabit each apartment, it is more than probable that each family knew their own, and always entered at their own doors, without any further connection with their neighbours than a friendly intercourse, or to join their united labours in erecting their separate habitations, and to help in adding to the dam when requisite.

The old story about the beaver using its broad flat tail as a trowel to smooth over the mud of its house, it is hardly necessary to add is a fiction. When it originated we are unable to say; the ancient natural history writers, Aristotle and Pliny, do not allude to it. The error no doubt arose from the habit of the animal constantly slapping its tail as it moves along.

In his chapters on Social Insects, Mr. Wood gives us, amongst other interesting matter, an account of one of the most terrible insects in existence; this is the Driver Ant (Anomma arcens) of Western Africa. Like many species of ants, this insect is remarkable for its sagacity and skill. We shall conclude our sketch of the architecture of animals with a notice of the habits of this insect. It is a curious fact that though found in immense numbers, it has never yet been discovered in the winged condition, and the male and female are unknown.

'The workers are uniform in colour, but exceedingly variable in size. Their hue is deep brownish black, and their length varies from half an inch to one line, so that the largest workers nearly equal the common earwig, while the smallest are no larger than the familiar red ant of our gardens. They are called driver-ants because they drive before them every living creature. There is not an animal that can withstand the driver-ants. In their march they carry destruction before them, and every beast knows instinctively that it must not cross their track. They have been known to destroy even the agile monkey when their swarming host had once made a lodgment on its body, and when they enter a pigstye they soon kill the imprisoned animals, whose tough hides cannot protect them from the teeth of the driver-ants. Fowls they destroy in numbers, killing in a single night all the inhabitants of the hen-roost, and having destroyed them have a curious way of devouring them.'

It appears according to the experiments of the Rev. Dr. Savage, that the ants begin at the base of the beak, and pull out the

feathers

feathers one by one, until they have stripped the fowl regularly backwards, working over the head, along the neck, and so on to the body. Not having sufficient strength to pull the feathers out by main force, they grub them out by the roots, then pull the bird to pieces and devour it. So completely, we are told, is the dread of the driver ant in every living creature, that on their approach whole villages are deserted.

Their sallies are made in cloudy days and in the night, chiefly in the latter. This is owing to the uncongenial influence of the sun, an exposure to the direct rays of which, especially when the power is increased by reflection, is almost instantaneously fatal. If they should be detained abroad till late in the morning of a sunny day by the quantity of their prey, they will construct arches over their path, of dirt agglutinated by a fluid secreted from their mouth. If their way should run under thick grass, sticks, &c., affording sufficient shelter, the arch is dispensed with; if not, so much dirt is added as is necessary to eke out the arch in connection with them. In the rainy season, or in a succession of cloudy days, the arch is seldom visible.'

When the rain descends in such torrents as to flood whole tracts of country, and the habitations of the driver ants are deluged, the insects adopt the following means of escaping destruction:

'As soon as the water encroaches upon their premises they run together and agglomerate themselves into balls, the weakest (or "the women and children," as the natives call them) being in the middle, and the large and powerful insects on the outside. These balls are

much lighter than water, and consequently float on the surface until the floods retire, and the insects can resume their place on dry land. The size of the ant balls is various, but they are, on an average, as large as a full-sized cricket-ball. One of these curious balls was cleverly caught in a handkerchief, put in a vessel, and sent to Mr. F. Smith, of the British Museum.'

Their manner of crossing streams is equally curious, though shared by other species of ants.

Crawling to the end of a bough which overhangs the water, they form themselves into a living chain, and add to its length until the lowermost reaches the water. The long wide-spread limbs of the insect can sustain it upon the water, especially when aided by its hold on the suspended comrade above. Ant after ant pushes forward, and the floating portion of the chain is thus lengthened until the free end is swept by the stream against the opposite bank. The ant which forms the extremity of the chain then clings to a stick, stone, or root, and grasps it so firmly that the chain is held tightly, and the ants can pass over their companions as over a suspension bridge.'

We must end this sketch of a very attractive subject, and

refer

refer those who take an interest in natural history to the works at the head of this article. Mr. Rennie's book has long and deservedly been considered a standard book on the architecture of insects, and we have much pleasure in cordially recommending Mr. Wood's recent work on the architecture of animals generally. The author is a careful observer of nature, and writes in a pleasant and attractive manner. The illustrations for the most part are executed with great spirit, and we have no doubt that Homes without Hands' will increase in popularity as it becomes more widely known.

ART. IV.-1. Das Leben Jesu für das Deutsche Volk, &c., By D. F. Strauss. Leipzig, 1864.

2. Das Leben Jesu. By D. F. Strauss.

3. Dus Charakterbild Jesu. By Daniel Schenkel. Wiesbaden, 1864.

4. Das Bild Christi. By J. F. von Oosterzee.

1864.

Hamburg,

5. Der Geschichtliche Christus. By Theodor Keim. Zurich, 1865.

6. Jesus Christ, son Temps, sa Vie, son Euvre. By E. de Pressense. Paris, 1866.

7. Untersuchungen über die Evangelische Geschichte, u. s. w. By C. Weizsäcker. Gotha, 1864.

8. Wann wurden unsere Evangelien verfasst? By Constantin Tischendorf. Leipzig, 1865.

9. Der Ursprung unseren Evangelien, u. s. w. By Dr. Gustav Volkmar. Zurich, 1866.

THI

HIRTY years ago the 'Life of Jesus' of Strauss startled the world like a clap of thunder out of a calm sky. Theology has never since ceased to feel that shock. No German writer, of whatever school, has been able to banish the recollection of it from his pages. It was a book that marked an epoch; not, indeed, in the same sense as the 'Summa' of Aquinas, or the 'Organon' of Bacon, for these constructed, whilst that strove only to destroy. These were positive, and succeeding thinkers were obliged to take them up and carry on the thoughts they presented. The work of Strauss was negative: no wish to retain anything weakened the arm that wielded the destroying hammer; no mistrust as to what the world might be without Christianity, prevented him from doing his very utmost towards its destruction. In the name of criticism he declared that the Gospels were almost valueless as historical materials; in the name of science he pro

nounced

nounced that miracles were impossible; in the name of the highest philosophy he professed to show the process by which the idea of such a character as that of Jesus Christ might be evolved out of the minds of a people, if but a few historical elements were given them.

The Life of Jesus,' considered as a mine sprung under the ancient theology for the purpose of destroying it utterly, is a most remarkable production. But it claims a different rank from this. It is a work of science and philosophy. Christianity and the character of its author are facts; and this earnest disciple (ardent we must not apply to one whose thoughts are hard, clear, chilling, and crushing as the iceberg) of the new school of Hegel, having demolished the grounds on which these facts used to rest, will show us in the name of science the new grounds on which they are henceforth to repose.

What reasoning, what fierce denunciation, what wild wailing this book drew forth from astonished Christendom need not now be recalled,

The man who, after playing bowls with spectres in the Catskill mountains, fell asleep, and awoke in the next generation, found, according to Irving's charming story, a state of matters in his native village not very flattering to his pride, or comforting to his affections. Dr. Strauss has just performed a similar feat, after thirty years of slumber; and in his case, too, the results are not adequate to his wishes. His scientific principles, whatever they are, ought by this time to have produced settled results. This is the property, and therefore the test, of all true science, that whatever difficulties it may contend with at first, it conquers them by its power of grouping facts already known, of explaining new ones that occur, and of ordering and arranging ideas. Aristotle was right when he said that all science must be capable of being taught. After thirty years then, there should be, if the principles are true, something like a concord of testimony from all the facts since examined, something like an agreement among theologians upon some settled principles, if not those of Strauss, then those to which subsequent verification has brought his principles down. This, however, is by no means what the irrefragable Doctor finds; and the new 'Life of Jesus' surveys the state of things with no great approbation. On this head we will allow the author to speak for himself, compressing his critical survey a good deal, and paraphrasing it, but allowing him to distribute his praise and blame.

The work we published thirty years ago, comparable in its way to "Kant's Critique of Pure Reason," was intended to demolish all old prejudices of theology, and to substitute pure science for the same.

And