76 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
As to the cause of the poisoning, we have* not perfectly 
satisfactory knowledge. In general, it appears to be due to 
the exposure of the Mussels to impure waters. Some years 
ago a case of violent poisoning in Wilhelmshaven, in North 
Germany, which resulted in the death of several persons, led 
to a careful investigation. It was shown that the fatal Mussels 
had been taken from the harbor of the town, in which the 
water, though salt, is quite stagnant, clear water entering in 
small quantities at high tide only. Fish could not live in it, 
and even the all-enduring eel became weak and helpless, 
Experiments proved that all the Mussels of the still water 
were poisonous, but that upon being removed to clear water 
they quickly became harmless; on the other hand, perfectly 
good Mussels, placed in the harbor, were soon very poisonous.. 
Prof. Virchow found that only the liver contains the poison, 
and that it can be rendered harmless by cooking the animal 
in a solution of soda. The best antidote is said to be a 
quantity of milk. The safest way, according to this investi- 
gator, is to remove the liver from every specimen to be eaten. 
It is a large yellowish-brown soft body enclosing the stomach 
on the upper side, and involved in numerous loops of the 
intestine. The conclusion to be drawn from these facts is, 
that Mussels from stagnant or impure waters should always 
be avoided, and everybody ought, before eating them, to know 
whence they came. It is thought, too, that they may be 
injurious when taken from docks in which copper-bottomed 
ships are moored, or from harbors in which there are mineral 
lodes exposed to the action of the water. Several writers have 
thought that the striped variety { var . pellucidus) is poisonous. 
As mentioned above, however, these cases of poisoning are very 
rare, and should prove no impediment to their free use, proper 
precautions being taken to bring the supply from pure waters. 
(c) Its Use as a Fertilizer. 
When a great bed of Mussels is exposed on a flat in an 
estuary, it is constantly catching the fine silt which the fresh 
water deposits when it meets the salt. The animals live their 
short lives, die, and are buried beneath their progeny. The 
