PEARL MUSCLE. 373 



The servant, who put the Marquis upon this stratagem, had pre. 

 viously assured his master that these pearls withstood heat and 

 moisture; that they were not easily scratched, and that their weight 

 was the same with that of real pearls. This anecdote, which is 

 detailed by Professor Beckman, proves that artificial pearls did not 

 become common, even in France, till many years after their first 

 invention. 



The trade of artificial pearl. making is still carried on at Paris by 

 the descendants of Jacquin, the original inventor ; but they are also 

 made in many other parts of Europe, and with several variations as 

 to the colour and kind of the glass, and other minute particulars. 



The mjtiJus margaritiferus of Linnaeus, or great pearl muscle, is 

 not the only shell which produces pearls. A species of the genus 

 called mya, and which is the mya margaritifera of Linnaeus, also 

 produces pearls, though, in general, of a far smaller size, and of 

 inferior quality. This sh 11 is commonly called the European pearl 

 muscle, and much resembles the common river muscle, though of a 

 different genus. It is found in rivers in the north of England, in 

 Scotland, Ireland, and many other parts of Europe. In the seven- 

 teenth century several rich pearls of large size are said to have been 

 obtained from this >hell, in some of the rivers of Ireland. One was 

 valued at upwards of 4/., another at 10/., and a third at no less 

 than 40/. As a species, the European pearl-muscle, or more pro- 

 perly, mya, is distinguished bv having a thick, coarse, blackish shell, 

 jenerall\ barked or decorticated towards the hinge *. 



I have before mentioned, when speaking of the real or Indian 

 pearl-shell, the French art of making artificial pearls. There exists 

 also an art, said to be often practised by the Chinese, and which 

 Li'inaeus attempted to put in practice in Europe, of forcing, as it 

 were, the production of pearls, in the mya margaritifera, or Euro- 

 pean pearl muscle, by piercing the outside of the shell in several 

 places, so as barely not to make complete perforations. In this 

 case, the animal, conscious of the weakness or deficiency of the shell 

 in those spots, soon begins to secure the weakened parts by depo- 

 . , t ' - 



* Pearly concretions are also occasionally formed in all shells, and are of 

 different colours, according to that of the shell in which they are formed. 

 Thus, the animal of the large univalve shell, called the strombus gigas, or great 

 rose-mouthed strombus, sometimes produces pearly concretions of a fine ro*e- 

 colour. 



2B3 



