of the Fishery Board for Scotland. 



393 



contains an account of the poisonous properties of mussels. It appears 

 that the consumption of oysters did not cause more frequent accidents 

 at the period of spawning than away from the time of reproduction, 

 poisoning arising only from those which have undergone a chemical 

 change, or have lived in waters made filthy by organic matters in course 

 of decomposition. The more frequent poisoning by mussels has been 

 attributed to a variety of causes, (1) to a small crab (Pinnotheres pisum) 

 which often lives within the mussel shell ; (2) the presence of the spawn 

 of starfishes j (3) the presence of copper, Bouchardat having shown that 

 mussels taken from copper-bottomed ships contained this metal : (4) to an 

 idiosyncrasy of the individual poisoned. The first two explanations have 

 been shown to be unfounded ; and although copper is often present in 

 mussels growing on old hulks, &c, it has been shown experimentally 

 that mussels living in water containing copper in solution die before they 

 accumulate sufficient of the metal to make them poisonous. 



On 17th October 1885, the workmen of the Arsenal of Wilhelms- 

 haven ate mussels attached to the wooden keel of two vessels sunk 

 in the port. Xineteen of them were attacked seriously, and four 

 died in some hours. The swallowing of 5 or 6 mussels was sufficient 

 to cause grave symptoms of poisoning. Animals which had eaten 

 equally of these mussels succumbed like the men, very quickly. 

 These mussels were eaten quite fresh from the water, but they 

 exhaled a nauseous smell. MM. Brieger and Schmidtmann analysed 

 them, and obtained from them a very active alcoholic extract, which 

 would be a ptomaine developed under the influence of a special microbe. 

 According to M. Wolff, the principal poison would be seated exclusively 

 in the liver. M. Salkowski has discovered that the alcoholic extract 

 became inactive when treated with carbonate of soda ; in the same way 

 mussels cooked for ten minutes with carbonate of soda had lost their 

 intoxicating property ! Professor Virchow also made an interesting 

 experiment with these mussels ; he kept some alive during two months 

 in an aquarium, and proved that they had ceased to be dangerous. 

 According to MM. Lohmayer and Kobelt, the poisonous mussel of 

 Wilhelmshaven belongs to a variety introduced from England, probably by 

 ships that carried it fixed to their keels : this would be Mytilus edulis, 

 var. pellucidus. However this may be, M. Schmidtmann has shown that 

 the same mussel taken in the outer port was non-injurious, but that it 

 became poisonous after a sojourn of a fortnight in the docks ; it is the 

 same with the star-fishes, which, according to M. Wolff, become poisonous 

 and produce the same symptoms as the mussels, when they live in 

 stagnant waters. In England sailors will not eat mussels from non- 

 flowing waters and those polluted by docks and ports. Recently M. 

 Lustij has studied, comparatively from the point of view of 

 their action on the animal economy, mussels taken in the open sea at 

 Trieste and Genoa, and those taken from stagnant waters of the canals 

 and ports. In the first he has not found any microbe ; from the second 

 he has obtained by cultivation two microbes, the one inoffensive, the 

 other pathogenic ; this last, introduced into the digestive tube of 

 animals, causes death in one or two days. 



It appears then that the poisonous property of mussels is due to the 

 presence principally in the liver of a volatile organic alkaloid (Mytilo- 

 toxine of Brieger) developed under the influence of a particular microbe. 

 Almost all authors agree in acknowledging that poisonous mussels are 

 only found in stagnant waters or the filthy waters of ports, docks or 

 canals, and that the accidents caused by eating these shell-fish can be 

 noted at all seasons outside the period of reproduction, as the case of 



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