The literature of oyster-cookery may be passed over in silence. The curious may care to refer to M. S. Lovell’s _Edible British Mollusks_, where no less than thirty-nine different ways of dressing oysters are enumerated. It may, however, be worth while to add a word on the subject of _poisonous_ oysters. Cases have been known where a particular batch of oysters has, for some reason, been fatal to those who have partaken of them. It is possible that this may have been due, in certain instances, to the presence of a superabundance of copper in the oysters, and there is no doubt that the symptoms detailed have often closely resembled those of copper poisoning. Cases of poisoning have occurred at Rochefort through’ the importation of ‘green oysters’ from Falmouth. It would no doubt be dangerous ever to eat oysters which had grown on the copper bottom of a ship. But copper is present, in more or less minute quantities, in very many Mollusca, and it is more probable that a certain form of slow decomposition in some shell-fish develops an alkaloid poison which is more harmful to some people than to others, just as some people can never digest any kind of shell-fish.[230] These alkaloid developments from putrescence are called ptomaines. In confirmation of this view, reference may be made to a case, taken from an Indian Scientific Journal, in which an officer, his wife, and household ate safely of a basket of oysters for three days at almost every meal. The basket then passed out of their hands, not yet exhausted of its contents, and a man who had already eaten of these oysters at the officer’s table was afterwards poisoned by some from the same basketful.