tag="{http://www.w3.org/1999/xhtml}a">¹² "though they are accidental formations, and, of course, not always to be found in the shellfish which are known usually to contain them, still they are the products of a regular secretion, applied, however, in an unusual way, either to avert harm or allay irritation. That, in many instances they are formed by the oyster, to protect itself against aggression, is evident; for, with a plug of this nacred and solid material it shuts out worms and other intruders which have perforated the softer shell, and are intent on making prey of the hapless inmate: and it was apparently the knowledge of this fact that suggested to Linnaeus his method of producing pearls at pleasure, by puncturing the shell with a pointed wire. But this explanation accounts only for the origin of such pearls as are attached to the shell; while the best and greatest number, and, indeed, the only ones which can be strung, have no such attachment, and are formed in the body of the animal itself. 'The small and middling pearls,' says Sir Alexander Johnston, 'are formed in the thickest part of the flesh of the oyster, near the union of the two shells; the large pearls almost loose in that part called the beard.' Now, these may be the effect merely of an excess in the supply of calcareous matter, of which the oyster wishes to get rid; or, they may be formed by an effusion of pearl, to cover some irritating and extraneous body." The reality of the latter theory is strengthened, if not proved by the Chinese forcing the swan muscle to make pearls by throwing into its shell, when open, five or six minute mother-of-pearl beads, which, being left for a year, are found covered with a crust perfectly resembling the real pearl. Such is one method of getting artificial pearls. The extraneous body which naturally serves for the nucleus, appears to be very often, or, as Sir E. Home says, always, a blighted ovum or egg. This theory which, however, is here but partly explained, has been fully adopted by Sir E. Home:—"if," says the enthusiastic baronet, "I shall prove that this, the richest jewel in a monarch's crown, which cannot be imitated by any art of man, either in the beauty of its form or the brilliancy and lustre produced by a central illuminated cell, is the abortive egg of an oyster enveloped in its own nacre, of which it receives annually a layer of increase during the life of the animal, who will not be struck with wonder and astonishment?" And, we must add, that the proofs are very much in favour of this conclusion.

ROMAN TOMBS.

"Tombs," observes the clever author of Rome in the Nineteenth Century, "formed a far more prominent feature in ancient communities than in ours. They were not crowded into obscure churchyards, or hidden in invisible vaults, but were sedulously spread abroad in the most conspicuous places, and by the sides of the public ways." Hence we may add, the "Siste Viator" (traveller, stop!) so common upon tombs to this day. But why are not tombs placed by the roadside in our times? "It would seem," says the writer just quoted, "as if these mementos of mortality were not so painful or so saddening to Pagans as to Christians; and, that death, when believed to be final dissolution, was not so awful or revolting as when known to be the passage to immortality. I pretend not to explain the paradox, I only state it; and, certain it is, that every image connected with human dissolution, seems now more fearful to the imagination, and is far more sedulously shunned, than it ever was in times when the light of Christianity had not dawned upon the world."¹³

The high-ways do not, however, appear to have been the earliest sites of tombs. According to Fosbroke, "the veneration with which the ancients viewed their places of sepulture, seems to have formed the foundation upon which they raised their boundless mythology; and, as is supposed, with some probability, introduced the belief in national and tutelary gods, as well as the practice of worshipping them through the medium of statues; for the places where their heroes were interred, when ascertained, were held especially sacred, and frequently a temple erected over their body, hallowed the spot. It was thus that the bodies of their fathers, buried at the entrance of the house, consecrated the vestibule to their memory, and gave birth to a host of local deities, who were supposed to hold that part of the dwelling under their peculiar protection. Removed from the dwelling-houses to the highways, the tombs of the departed were still viewed as objects of the highest veneration."¹⁴

Our readers may remember that the ancient Romans never permitted the dead to be buried within the city,¹⁵ a practice well worthy the imitation of its modern inhabitants. One of the Laws of the Twelve Tables was

Hominem mortuum in urbe ne sepelito, neve urito,

(neither bury nor burn a dead body in the city.) But this law must be understood with this limitation, that the Senate occasionally granted exemption from it, to distinguished individuals, though so rarely, that a tomb within the walls of Rome seems to have been considered a reward of the most pre-eminent virtue.

The tombs of the Romans were characterized by their impressive grandeur. The Roman satirists, Juvenal and Horace, censure the pomp and splendour of the tombs, particularly those on the Via Appia. "On that 'Queen of Ways,' and way to the Queen of Cities, were crowded the proud sepulchres of the most distinguished Romans: and their mouldering remains still attest their ancient grandeur." Again, "those who have traced the long line of the Appian Way, between its ruined and blackening sepulchres, or stood in the Street of Tombs that leads to the Gate of Pompeii, and gazed on the sculptured magnificence of these marble dwellings of the dead, must have felt their solemnity, and admired their splendour."¹⁶

Antiquarian writers have carefully classified the Roman tombs. We have, however, only space to remark generally, that the sepulchres were either square, circular, or pyramidal buildings, and with one entrance only, which was invariably on the side farthest from the public road. They usually consisted of a vault in which the urns and sarcophagi were deposited, and a chamber above, in which the statues or effigies of the dead were placed, and the libations and obsequies performed. These sepulchres were usually places of family interment, but sometimes they were solitary tombs. Of the latter description is the Tomb of Caecilia Metella, which is generally acknowledged to be the most beautiful sepulchral monument in the world. It consists of a round tower formed of immense blocks of Tiburtine stone, fixed together without cement, and adorned with a Doric marble frieze, on which are sculptured rams' heads festooned with garlands of flowers. "That they are rams' heads, must be evident to any one who will take the trouble to examine them, though they are usually denominated the heads of oxen, because the tomb itself is vulgarly called Capo di Bove. But this name is obviously derived from an ox's head, (the arms of the Gaetani family,