FOOD POISONING. 49 



the edible kind, and that the flesh of the poisonous mussel is yellow; 

 the water in which they are boiled becomes bluish. 



However, this belief in a poisonous species is now admitted to 

 l)e erroneous. At one time it was suggested that mussels became 

 hurtful by absorbing the copper from the bottoms of vessels, but 

 Christison made an analysis of the mussels that poisoned the men 

 mentioned by Combe, with negative results, and also pointed out 

 the fact that the symptoms were not those of poisoning with cop- 

 per. Some have held that the ill effects were due wholly to 

 idiosyncrasies in the consumers, but cats and dogs are affected 

 in the same way as men are. It has also been believed that 

 all mussels are poisonous during the period of reproduction. This 

 theory is the basis of the popular superstition that shellfish 

 should not be eaten during the months in the name of which 

 the letter " r " does not occur. At one time this popular idea 

 took the form of a legal enactment in France forbidding the sale 

 of shellfish from May 1st to September 1st. This widespread 

 idea has a grain of truth in it, inasmuch as decomposition is 

 more likely to alter food injuriously during the summer months. 

 How^ever, poisoning with mussels may occur at any time of 

 the year. 



It has been pretty well demonstrated that the first two forms 

 of mussel poisoning mentioned above are due to putrefactive pro- 

 cesses, while the paralytic manifestations seen in other cases are 

 due to a poison isolated a few years ago by Brieger, and named 

 by him mytilotoxin. Any mussel may acquire this poison when it 

 lives in filthy water. Indeed, it has been shown experimentally 

 that edible mussels may become harmful when left for fourteen 

 days or longer in filthy water; while, on the other hand, poisonous 

 mussels may become harmless if kept four weeks or longer in clear 

 water. This is true not only of mussels, but of oysters as well. 

 Some years ago, many cases of poisoning from oysters were re- 

 ported at Havre. The oysters had been taken from a bed near 

 the outlet of a (Irain from a public water closet. Both oysters and 

 mussels may harbor the typhoid bacillus, and may act as carriers 

 of this germ to man. 



There should be most stringent police regulations against the 

 sale of all kinds of mollusks, and all fish as well, taken from filthy 

 waters. Certainly one should avoid shellfish from impure waters, 

 and it is not too much to insist that those offered for food should 

 be washed in clean water. All forms of clam and oyster broth 

 should be avoided when it has stood even for a few hours at sum- 

 mer heat. These preparations very quickly become infected with 

 bacteria, which develop most potent poisons. 



