160 M. A. Duméril on Venomous Fishes. 
1. The mackerel taken at St. Helena is, according to Quar- 
rier, constantly poisonous if kept for a single night; if pre- 
pared, however, on the same day on which it is caught, it is 
not so. 
2. The inhabitants of the Antilles say that the Bonito should 
be dressed for the table as soon as it is taken from the water*. 
3. The Chinese eat the Tetraodon ocellatus, one of their best 
fishes, as soon as it is capturedt. , 
4. The instances of poisoning belong almost exclusively to 
countries where the temperature is very high, and more espe- 
cially to the great heats of the year—that is to say, when de- 
composition is most rapid. 
5. Finally, it is to a phenomenon of this sort that we must 
attribute the change of colour which takes place on a silver 
spoon plunged into the vessel in which the fish is being cooked, 
black sulphuret of silver being formed as a consequence of the 
hberation of sulphuretted hydrogen, which is a sure indication 
of a decay of tissue. 
VIII. 
In fishes that are thus baneful, it is perhaps sometimes a 
condition of disease which alters the natural qualities. 
IX. 
I pass over in silence the réle attributed to copperas-beds 
in certain marine bottoms. In the already cited memoir by 
M. Moreau de Jonnés (pp. 14-19) there are some remarks of 
sufficient weight, tending to demonstrate the impossibility of 
accepting the hypotheses which have been put forward on this 
subject. 
In conclusion, it is evidently not proper to adopt any one of 
* The necessity of eating this fish without delay has often been remarked; . 
but an instance of the danger incurred by neglecting to do so is given in a 
memoir by M. Morvan de Lannilis (Journ. de Chim. Méd., Pharm., Toxicol., 
rédigé par A. Chevallier, 4° série, t. iii. p. 719, 1857), who relates that 
five persons, having experienced no ill effects after eating, on board the 
corvette ‘Corneline,’ at Teneriffe, some Bonitos freshly caught, suffered 
severely for an hour or two on the following day for having breakfasted on 
some of those reserved over night. M.Guyon witnessed at Martinique, in 
1822, a case of poisoning which, though not mortal, disturbed the health 
of an entire company of soldiers for several hours most fearfully. The 
repast, which took place at 3 o’clock p.m., consisted of Bonitos bought 
in the afternoon of the preceding day, and supposed to have been taken 
in the morning of that day. Thus the thirty hours since the fish were 
first captured sufficed for a most considerable alteration in their condi- 
tion. 
+ According to Forster, this is the fish eaten by the Japanese when they 
wish to commit suicide. 
