The Pearl, its story, its charm, and its value

by Wallis Richard Cattelle

The best pearls and the largest number are found usually in mature shells which are distorted; it has been stated as a possibility, that in the future some of the new rays will be used in fisheries where the pearl is the main object of the fisher, to ascertain if the oyster contains any before destroying it. M. Dubois of Lyons has experimented with Roentgen rays for that purpose.

As the fish is enormously prolific it is more probable however that effort will be directed instead toward the preservation of the mollusk from the enemies and accidents which are occasionally greater than its productiveness.

One of the greatest dangers in Indian waters to a bed of young oysters is a little mollusk known locally in Ceylon as suran (Modiola). These cluster in masses on the sea bottom and spreading over the surface of the coral, crowd out the delicate young of oysters recently deposited.

The Japanese fisheries suffer from the occasional infection of the waters by a weed, dinoflagellata gonyaulax. It accumulates in immense quantities, causing a wide discoloration of the sea water and is very destructive to an oyster-bed. It is called the red current or red tide. So far no preventive or remedy has been found.

Hitherto the most general and fatal danger to oyster-beds has been the ungoverned extravagance of irresponsible fishers who seek to harvest in the present regardless of the future, but these are gradually being made amenable to restrictive laws as authorities awake to the value of the industry. A greater danger which threatens the unio of American streams, is the pollution of the water by the discharge of the refuse of factories and the sewage of cities into them. A mussel bed will recover in time when denuded by fishers, but sewage and poison kills it out entirely.

Although fresh-water pearl-bearing mussels are found in the streams of many countries, only in the United States are they taken in sufficient quantities to make the fishings important as an industry. They are to be found throughout the Mississippi drainage area and in part of that of the St. Lawrence. Few exist on the Pacific coast and those of the Atlantic coast are generally inferior as pearl-mussels. There are many varieties of the unio which yield pearls. Latin names are given by different writers to distinguish them, but as scientists differ in their classifications, the names are not always uniform and are not sufficiently well established to be useful, descriptively, to the general reader. In treating of the various kinds of pearl-bearing unios of the United States therefore in these pages, the common names by which they are known will as a rule be used with the scientific names appended, as revised by the department of mollusks of the United States National Museum.

From the times of Roman colonization until now, pearls have been taken from the mussels of British streams. There are three varieties of pearl-bearing mussels in Great Britain: Painter's mussel (U. pictorum), the Swollen River mussel (U. tumidus) and the Pearl mussel (U. margaritifera).

The first two occur only in the streams and ponds of England and Wales and the pearls found in them are of inferior quality. The latter inhabits the streams of Scotland and the northern counties of England and to some extent are found in Ireland and Wales also. The shell is oblong, rather flat and heavy and about five and one-half inches long. The exterior surface is rough, and blackish-brown; the pearly interior has a tint of flesh color mottled by stains of dull green. It was from this variety the Perthshire Tay pearls were taken, which gained so much notoriety in the middle of the eighteenth century when some fifty thousand dollars worth were sent to London from this stream in three years.

Scotch pearl-fishing was revived in 1860 and some fine ones were sold to Queen Victoria, the Empress of the French, the Duchess of Hamilton and others. Pearl-mussels have been found in Lochs Rannoch, Tay, Lubnaig and Earn, also in the Don, the Leith and other streams. Some are found in the Welsh streams, and the river Bann in Ireland was noted for the fine pearls found in it. Many years ago there was a pearl fishery at Omagh in the north of Ireland. An old writer claims that Cæsar obtained pearls of such bigness in Britain that he tried the weight of them by his hand.

The fishers wade for them in shallow pools, or thrust sticks between the open valves, or drag branches over them, for as soon as anything enters between the two shells they close upon it at once. The mussels are found generally set up in the sand of the river-bed with the open side, if the current is very strong, turned away from it. The custom of the peasantry is to fish for them in the autumn after harvest.