MARSHALL: ADDITIONS TO "BRITISH CONCHOLOGY." I25 



L. subovata Jeff, has been dredged in the Atlantic off Ireland in 

 i366f., and off the Butt of Lewis in 542f., by the 'Porcupine' ; also 

 in the Shetland-Faroe Channel, in 57of., by the 'Triton.' 



Mytilus edulis L. — In 1901, when the lightship at Boston, in 

 Lincolnshire, was put on the gridiron for overhauling, no less than six 

 tons of mussels were taken from her keel and sides. The propensity 

 of Mytihis to attach itself to the sheathing of ships is a fruitful cause 

 of food poisoning, though the latter may also arise from the practice 

 of taking mussels from the open sea and placing them in contaminated 

 waters to fatten or as a preserve for bait. There are many forms of 

 ptomaine or food poisoning in all preserved or stale provisions, but 

 that inherent in Mytilus is a perfect example of true ptomaine 

 poisoning, being caused by a ptomaine known as " mytilotoxin," 

 which has its source in stagnant waters and is generated in the 

 unusually large liver of the animal. Gwyn Jeffreys wrote that "the 

 ' faculty ' seems completely at fault as to the nature of this poison,"^ 

 but it is now known that mytilotoxin is a specific micro-organism, 

 highly dangerous, and may be acquired from eating either cooked or 

 uncooked mussels — so dangerous, indeed, that in acute cases fatal 

 results may ensue within two or three hours of their consumption. It 

 has been found fatal to animals if given by the mouth, although quite 

 innocuous if injected into the circulation. 



Grown under careful supervision and with proper care, however, 

 mussels are an excellent food. Those in most repute come from the 

 beds of St. Valery-sur-Somme, and especially from the bay of 

 L'Aiguillon, where it is said that mussels have flourished for more 

 than 800 years, and their consumption in Paris alone is estimated to 

 be worth nearly 10,000,000 francs per annum. They are palatable 

 and nutritious even in the wild state, but on the mud flats of St. 

 Valery, which comprise hundred of acres, mussel culture has been 

 brought to such a state of perfection that the artificial breeding, rearing 

 and fattening of the mussels, on the same principles which obtain in 

 ostreaculture, has brought them to a high degree of perfection. 



The rate of production is enormous, and is estimated at 300-fold 

 per annum. The brood mussels are brought from the sea bed and 

 laid down on prepared grounds, which are set with interlaced rows 

 of stakes ; in due season they spawn plentifully, and the spat, 

 finding a congenial environment, with an admixture from the sweet 

 waters of the Somme, grow rapidly, and at the end of a year the germ 

 can be brought to those points of size, colour and flesh which enable 

 it to be sent to market, developing in that interval into full-grown 

 mussels sin. in length by half that width, free from disease or blemish 



I Brit. Conch., vol. ii., p. ic 



