On the Economical Uses of some species of Testacea. 69 
neglected, increased in price greatly beyond their value, and superior 
often to the price of oriental ones when bought in the east.* At 
present we are not aware that they are sought for, except as curi- 
osities. 
Natural history.—This shell is common to most of the rivers of 
Europe, but is chiefly found in those which are violent and rapid, 
and in the temperate or colder climates. In Norway and Sweden 
they abound, and they are found plentiful in the streams of West- 
ern Siberia.t In Great Britain they are common in the English, 
Welsh, and Scotch, and some of the Irish rivers ; in al] which the 
fisheries were formerly prosecuted. The same opinion as to the 
formation of the pearls in these was held, as with respect to the 
last species; and the supposition, that they were formed of dew, or 
of eggs which had not been evacuated, was supported by scientific 
writers as late as the seventeenth century. 
In 1761 Linneus informed the King and council of Sweden that 
he had discovered an art by which muscles might be made to pro- 
duce pearls, and he offered to disclose the method for the benefit of 
the kingdom. This however was not done, but he disposed of the 
secret for about five hundred ducats toa German. At the death of 
this man it was offered for sale, sealed up to the highest bidder, but 
what became of it is not known. Linneus once showed Beekman a 
small box filled with pearls, and said, ‘ Hos uniones confect artificio 
meo, sunt tantum quingue annorum, et tamen tam magni ;” and he 
declared that he could succeed in the same manner with all kinds of 
muscles.{ They lie in the mud, generally sticking up in a horizon- 
tal position by one e 
Fisheries. —Lying generally j in shallow water, little exertion or 
skill is necessary in procuring them, and the business was probably 
never sufficiently extended or valuable to cause either their cultiva- 
tion-or particular protection. The manner practised in procuring them 
in the north of Ireland in 1660, is described in the Philosophical Trans- 
actions, and exhibits neither art, nor much intelligence. Inthe warm 
months before the harvest, while the rivers were low and clear, the 
poor people waded into the water, and some with their toes, some 
with wooden tongs, and others with a sharpened stick, thrust into 
the open shell, brought them to the surface ; and although by com- 
* Macpherson, III. 419. Bruce, VII. 321. 
+ Cochrane’s Pedestrian Tour. + Beekman, II. 5—11. 
