MTTILOTOXISMVS. 191 



sels. It was formerly believed that the effects were due to the cop- 

 per which the animals obtained from the bottoms of vessels, but as 

 Christison remarks, copper does not produce these symptoms. More- 

 over, Christisou made analysis of the mussels which produced the 

 symptoms observed by Combe, and was unable to detect any copper. 

 Bouchardat found copper in some poisonous mussels, but he does not 

 state the amount of the metal nor the source of the animals. Edwards 

 advanced the theory that the symptoms were wholly due to idiosyn- 

 crasy of the consumer. This certainly is not a tenable hypothesis 

 in such instances as those reported by Combe and Schmidtmann, 

 where a large number or all those who partook of the food were 

 affected. Coldstream stated that the livers of poisonous mussels are 

 larger, darker, and more brittle than normal, and these changes he 

 believes are due to a diseased condition of the animals. Many have 

 supposed that the poisonous effects were due to a peculiar species of 

 medusa upon which the mussels feed, and De Beume found in the 

 vomited matter of one person some medusae and he states that these 

 are most abundant during the summer, when mussels are most fre- 

 quently found to be poisonous. The theory of Burrows that mussels 

 are always poisonous during the period of reproduction at one time 

 received considerable credit ; however, cases of poisoning have oc- 

 curred at different seasons of the year. In 1872, Crumpe suggested 

 that there is a species of mussel which is in and of itself poisonous, 

 and this species is often mixed with the edible variety. It has been 

 stated that the poisonous species has a brighter shell, a swe^t, more 

 penetrating, bouillon-like odor than the non-poisonous ; also that the 

 flesh of the former is yellow and that the water in which they are 

 cooked is bluish. This theory, however, is opposed by the majority 

 of zoologists. Mobius states that the peculiarities of the supposed 

 poisonous variety pointed out by Virchow and Schmidtmann are 

 really due to the conditions under which the animals live, the amount 

 of salt in the water, the temperature of the water, whether it is 

 moving or still water, the nature of the bottom, etc. He also states 

 that the sexual glands, which form the greater part of the mantle, are 

 white in the male and yellow in the female. The theory of a poison- 

 ous species has been abandoned since it has been shown that edible 

 mussels may become poisonous if left in filthy water fourteen days or 

 longer, and, on the other hand, poisonous ones may become fit for 

 food if kept for four weeks in good water. 



Cats and dogs which have eaten voluntarily of poisonous mussels 

 have suffered from symptoms similar to those observed in man ; and 

 rabbits have been poisoned by the administration of the water in 

 which the food has been cooked. A rabbit treated in this manner 

 by Schmidtmann died within one minute. From these mussels 

 Brieger extracted the ptomain mytilotoxin, which will be discussed 

 in a subsequent chapter. Whether or not those mussels which pro- 



