ON GREEN CYSTERS. 81 
duce such effects. It also appears that after death a certain 
form of slow decomposition may occur in shellfish which 
develops the same poison in large quantity. It is probable 
that the tissues, either living or dead, develop an alkaloid in 
greater or less abundance which is extremely poisonous to 
man and to which some persons are more sensitive than others.! 
Probably the deadly-poisonous Teleostean fish which are occa- 
sionally eaten by mistake at the Cape and in Japan, owe their 
injurious property to the same or a similar alkaloid. When 
therefore we find reports of persons having been poisoned by 
Oysters or by Mussels which have grown upon or in the vicinity 
of a copper-bottomed ship (as, for instance, in the ‘ Edinburgh 
Med. and Surg. Journal,’ vol. iv, p. 400), we are not justified 
in ascribing the colic and vomiting which such persons have 
suffered to the presence of copper in the Molluscs derived 
from the copper of the ship. It is known that Mussels and 
Oysters may produce these symptoms when grown apart from 
any special source of copper ; and, on the other hand, it is Not 
known that even when growing near or on copper, any Mollusc 
can take up into its system an abnormal amount of copper. 
It is to be noted that there is no observation on record of 
Mussels, Oysters, Barnacles, or other marine organisms, exhib- 
iting a green tint when removed from proximity to the 
copper-bottom of a ship ; and, indeed, there is no evidence that 
any organism can live when sufficiently impregnated with 
copper to assume even a pale green tint. 
Whilst there are so many considerations which explain the 
origin of the notion that copper may be responsible for the 
green colour of the “huitres de Marennes,” although that 
metal has really nothing to do with it, it is extremely remark- 
1 The name “ Ptomiains” has been applied to these substances which are 
only just beginning to be closely studied by chemists. From putrescent fish 
has recently been obtained a definite crystalline body, to which the name 
“Gadinin” has been given ; and what is of extreme interest and importance 
is that its formation is ascribed to the action of Bacteria upon the albumens 
of the fish. It is probable that observers will be able to identify and isolate 
the particular Bacterium which produces each particular Ptomain: See 
Brieger * Ueber Ptomaine,” Berlin, 1885. 
VOL, XXVI.——-NEW SER. Vy 
