CHAP. 54.—PEARLS; HOW THEY ARE PRODUCED, AND WHERE.

The first rank then, and the very highest position among all valuables, belongs to the pearl. It is the Indian Ocean that principally sends them to us: and thus have they, amid those monsters so frightful and so huge which we have already described,[1] to cross so many seas, and to traverse such lengthened tracts of land, scorched by the ardent rays of a burning sun: and then, too, by the Indians themselves they have to be sought in certain islands, and those but very few in number. The most productive of pearls is the island of Taprobane, and that of Stoidis, as already mentioned[2] in the description of the world; Perimula,[3] also, a promontory of India. But those are most highly valued which are found in the vicinity of Arabia,[4] in the Persian Gulf, which forms a part of the Red Sea.

The origin[5] and production of the shell-fish is not very different from that of the shell of the oyster. When the genial season of the year[6] exercises its influence on the animal, it is said that, yawning, as it were, it opens its shell, and so receives a kind of dew, by means of which it becomes impregnated; and that at length it gives birth, after many struggles, to the burden of its shell, in the shape of pearls, which vary according to the quality of the dew. If this has been in a perfectly pure state when it flowed into the shell, then the pearl produced is white and brilliant, but if it was turbid, then the pearl is of a clouded colour also; if the sky should happen to have been lowering when it was generated, the pearl will be of a pallid colour; from all which it is quite evident that the quality of the pearl depends much more upon a calm state of the heavens than of the sea, and hence it is that it contracts a cloudy hue, or a limpid appearance, according to the degree of serenity of the sky in the morning.

If, again, the fish is satiated in a reasonable time, then the pearl produced increases rapidly in size. If it should happen to lighten at the time, the animal shuts its shell, and the pearl is diminished in size in proportion to the fast that the animal has to endure: but if, in addition to this, it should thun- der[7] as well, then it becomes alarmed, and closing the shell in an instant, produces what is known as a physema,[8] or pearl-bubble, filled with air, and bearing a resemblance to a pearl, but in appearance only, as it is quite empty, and devoid of body; these bubbles are formed by the abortion of the shellfish. Those which are produced in a perfectly healthy state consist of numerous layers, so that they may be looked upon, not inappropriately, as similar in conformation to the callosities on the body of an animal; and they should therefore be cleaned by experienced hands. It is wonderful, however, that they should be influenced thus pleasurably by the state of the heavens, seeing that by the action of the sun the pearls are turned of a red colour, and lose all their whiteness, just like the human body. Hence it is that those which keep their whiteness the best are the pelagie, or main-sea pearls, which lie at too great a depth to be reached by the sun's rays; and yet these even turn yellow with age, grow dull and wrinkled, and it is only in their youth that they possess that brilliancy which is so highly esteemed in them. When old, too, the coat grows thick, and they adhere to the shell,[9] from which they can only be separated with the assistance of a file.[10] Those pearls which have one surface flat and the other spherical, opposite to the plane side, are for that reason called tympania,[11] or tambour-pearls. I have seen pearls still adhering to the shell; for which reason the shells were used as boxes for unguents. In addition to these facts, we may remark that the pearl is soft[12] in the water, but that it grows hard the instant it is taken out.

1. In c. 2 of the present Book.

2. In B. vi. cc. 24 and 28.

3. See B. vi. c. 23. Ælian, Hist. Anim. B. xv. c. 8, says to the same effect, but calls it "Perimuda, a city of India."

4. Ælian, Hist. Anim. B. x. c. 13. It has been already remarked, in the sixth Book, that the ancients looked upon the Persian Gulf as forming part of the Erythræan or Red Sea.

5. The pearl itself, Cuvier says, is nothing else but an extravasation, so to say, of the juices, whose duty it is to line the interior of the shell, to thicken and so amplify it; and consequently, it is produced by a malady. It is possible, he says, for them to be found in all shell-fish; but they have no beauty in them, unless the interior of the shell, the nacre, or, as we call it, the mother of pearl, is lustrous and beautiful itself. Hence it is, that the finest of them come from the east, and are furnished by the kind of bivalve, called by Linnæus, "Mytilus margaritiferus," which has the most beautiful mother of pearl in the interior that is known. The parts of the Indian sea which are mentioned by Pliny, are those in which the pearl oyster is still found in the greatest abundance.

6. All this theory, as Cuvier says, is totally imaginary.

7. Isidorus of Charax, in his description of Parthia, commended by Athenæus, B. iii., says, on the other hand, that the fish are aided in bringing forth, by rain and thunder.

8. From the Greek fush/ma, "air—Bubble."

9. It sometimes happens, Cuvier says, that the secretion which forms the mother-of-pearl makes tubercles in the interior of the shell, which are the pearls adhering to the shell here spoken of.

10. Persius alludes to this in Sat. ii. 1. 66. "Hæc baccam conchæ rasisse;" "to file the pearl away from its shell."

11. From this passage we learn that the "tympana," or hand-drums of the ancients, were often of a semiglobular shape, like the kettle-drums of the present day.

12. Cuvier remarks that this is not the fact: the concretions are perfectly hard before the animal leaves the water.