At Tenby, they call Mytilus modiolus the poisonous mussel, and affirm that no one ever ventures to eat it.
Pearls are occasionally found in the common mussel, and also in the oyster, scallop, cockle, periwinkle, and pinna; but they are generally inferior in size and quality to those of the freshwater pearl-mussel, Unio margaritiferus; and Mr. Beckman, in his 'History of Inventions,' states that real pearls are found under the shield of the sea-hare (Aplysia), as has been observed by Bohadsch, in his book 'De Animalibus Marinis' (Dresdae, 1761). Our Scotch pearl-fishery has, within the last few years, been revived, and in 1860 Mr. Moritz Unger, a foreigner, on making a tour through the districts where the pearl-mussel abounds, found that the pearl-fishing was not altogether forgotten, many of the people having pearls in their possession, of which they did not know the value. He purchased all he could obtain; consequently, in the following year, many persons devoted their spare time to pearl-fishing, and during the summer months made as much as £8 to £10 weekly. The summer of 1862 was most favourable for fishing, owing to the dryness of the season, and the average price was from £2 6s. to 10s.; £5 being a high price. They now fetch prices varying from £5 to £20. The Queen purchased one Scotch pearl for 40 guineas; others at high prices have been bought by the Empress of the French and the Duchess of Hamilton, and Mr. Unger had a necklace of these pearls valued at £350.* In 1867, at the September meeting of the 'Perthshire Society of Natural Science,' attention was called to the probability of the ultimate extinction of the pearl-mussel Unio margaritiferus in the rivers near Perth, owing to the quantities destroyed in search of pearls, thousands of shells being left on the banks of the rivers where the pearl-fishers had pursued their searches.* These mussels are found in Lochs Earn, Tay, Rannoch, and Lubnaig, and in the Don, the Leith, and in many of the other Scotch streams; also in some of the Welsh rivers, from whence I have received fine specimens; in Ireland, near Enniskillen, and in the river Bann, which is noted for its fine pearls.
* 'Cruise of the Alert,' p. 48.
† Forbes and Hanley, 'Brit. Mollusca,' vol. ii. p. 185, ‡ 'Life and Adventures of John James Audubon,' edited by R. Buchanan, p. 246, chap. xiii.
* The 'Times,' December 24, 1863.
Sir Robert Redding, in a letter dated Dublin, October 13th, 1688, - as quoted by Dr. Boate in his 'Natural History of Ireland,' - says "that there are four rivers in the county of Tyrone abounding with pearl-mussels, all emptying themselves into Lough Foyle, whereon stands the town of Derry. There are also other rivers in the county of Dunnagall, a river near Dundalk, the Shure, running to Waterford . . . . And no doubt there may be many more that I do not know; all these places are at the feet of very great mountains. The manner of pearl-fishing is not extraordinary, the poor people, in the warm months, before harvest is ripe, whilst the rivers are low and clear, go into the water, some with their toes, some with wooden tongs, and some by putting a sharpened stick into the opening of the shell, take them up; and although by common estimate not above one shell in a hundred may have a pearl, and of those pearls not above one in a hundred be tolerably clear, yet a vast number of fair merchantable pearls, and too good for the apothecary, are offered for sale by those people every summer assize. Some gentlemen of the country make good advantage thereof, and myself, whilst there, saw one pearl bought for 50s., that weighed 36 carats, and valued at £40".
* 'Naturalist's Circular,' No. 17, October, 1867.
The pearl-mussels are collected in the same manner now, viz., by wading for them in shallow pools, or by thrusting a long stick between the valves when the shell is open. When a number have been collected they are left to decompose, when the pearls drop out.* They may also be found in Kerry, in the Moy, near Foxford, and in many of the other Irish rivers; and Mr. Buckland stated in the 'Field/ December 10th, 1864, that they abound near Oughterard, and that a man called "Jemmy the Pearl-catcher" told him he knew when a mussel had a pearl in it, without requiring to open it first, because "she (the mussel) sits upright with her mouth in the mud, and her back is crooked," that is, it is corrugated like a cow's horn. Bruce, in his 'Travels,' observes that the pearl-fishers of Bahrein informed him that they had no expectation of finding a pearl when the shell was smooth and perfect, but were sure to find some when the shell was distorted, and deformed; and he adds that this applies equally to the Scotch pearl-mussels. In France they also collect pearls from the pearl-mussels, and they generally sell them as foreign pearls. At Omagh, in the north of Ireland, there was formerly a pearl-fishery, and Gilbert, Bishop of Limerick, about 1094, sent a present of Irish pearls to Anselm, Archbishop of Canterbury. Pearls were much used in Irish religious ornaments in the fifteenth and sixteenth centuries. Scotch pearls were in demand abroad as early as the twelfth century. In the fourteenth century (1355) Scotch pearls are referred to in a statute of the Parisian goldsmiths, by which it was enacted that no worker in gold or silver should set them with oriental pearls, except in large ornaments or jewels for churches. In the reign of Charles I., the Scotch pearl trade was considered of sufficient importance to be worthy of the attention of Parliament.*
* 'Tour in Ulster'.
John Spruel in 'An Accompt Current betwixt Scotland and England,' Edinburgh, 1705, says, "If a Scotch pearl be of a fine transparent colour, and perfectly round, and of any great bigness, it may be worth 15, 20, 30, 40 to 50 rix-dollars, yea, I have given 100 rix-dollars (£16 9s. 2d). for one, but that is rarely to get such......I have dealt in pearl these forty years and more, and yet to this day 1 could never sell a necklace of fine Scots pearl in Scotland; nor yet fine pendants, the generality seeking for oriental pearls, because further fetcht. At this very day I can show some of our own Scots pearl, as fine, more hard and transparent than any oriental. It is true that the oriental can be easier matcht because they are all of a yellow water; yet foreigners covet Scots pearl". Suetonius says that the great motive of Caesar's coming to Britain was to obtain its pearls, and states that they were so large that he used to try the weight of them by his hand, and dedicated a breastplate made of them to Venus Genetrix.†