80 PROFESSOR RAY LANKESTER. 
demonstrated in a court of law that the Oysters seized in the 
market of Rochefort contained copper in poisonous doses. An 
ingenious defence was set up. It was admitted that these 
Oysters were coloured green by copper, but it was asserted that 
they were naturally so impregnated, and that they did not 
come from Marennes or the coast of France at all. The 
French green Oysters were declared to be free from copper and 
harmless, but (it was stated) these poisonous coppery green 
Oysters had been bought in ignorance by the fishmonger from 
Cornish fishermen and came from Falmouth. ‘“ Now,” it was 
argued, “it is well known that Cornwall abounds in copper, 
and what more natural than that a Cornish Oyster should 
become impregnated with that metal?” Without any evidence 
to prove either that there was any excess of copper in the sea- 
water whence these Oysters came, or that an Oyster can tolerate 
the presence of more copper in solution in seawater than the 
minute trace which is normally present, or that an Oyster or 
any other mollusc can take up such copper if present in suffi- 
cient quantity to colour it, the ingenious defence was admitted 
by the court, and the persons accused of selling poisonous 
Oysters were exculpated. 
It would perhaps be worth while to meet the assertions of 
those who persist in ascribing to Oysters and Mussels a peculiar 
power of assimilating copper, by direct experiment. Oysters 
should be kept in an aquarium into the water of which a 
certain amount of copper-salt should be introduced, or a plate 
of copper inserted. 
One fact which has served to strengthen the popular belief 
in a connection between copper and Molluscs, is the similarity 
of the symptoms produced by copper poisoning and by poison- 
ous Molluscs and shellfish. Occasionally Mussels, and more 
rarely Oysters, and not unfrequently Lobsters and Crayfish, 
have produced colic, vomiting, and even death, without being 
green or having any history which tends to connect them with 
copper. The condition of the shellfish in these cases appears 
to be an exaggeration of a normal condition, for there are 
some persons upon whom Molluscs and shellfish always pro- 
