234 PROCEEDINGS OF THE SCIENTIFIC ASSOCIATION* 
are reddened, the flesh immediately near the redness takes 
on a sharp and acrid iaste, as if it had been peppered ; 
and it causes imflammation in the throat, pains in the 
stomach, — diarrhoea, and even death, if one has eaten 
much of it. The police of Venice examine carefully the 
boats that bring in the fish, especially when the sirocco 
has delayed their arrival— and if ever so little touched they 
throw it into the sea. The freshest tunny ought to be sold 
within twenty-four hours.” — (C. & V. Hist. Nat. des Pois- 
sons, vol. viii., liv. ix.) 
What occurs with the tunny when decomposition com- 
mences, on the dead fish, is in reality the representation of 
the state of the living tissues when the cognate fishes as- 
sume the poisonous character. We say nothing of the oily 
fishes, such as the salmon, herring, &c., which are known 
when kept too long to give rise to symptoms of irritant 
poison. 
I think that the facts and inferences set out in this paper 
are a much nearer solution of the mystery of fish-poison 
than the crude guesses we see published as explanations. 
I do not know how far the following vital economy in res- 
pect of the keeping quality of fishes may be applied to the 
subject we have been endeavouring to illustrate, but I give 
it as making some weight in the tendency of fish-flesh to 
become prejudicial as food. “Physiologists have shown 
that the quantity of respiration is invariably as the degree 
of muscular irritability. It may be considered as a law, 
that those fish which swim near the surface of the water 
have a high standard of respiration,— a low degree of mus- 
cular irritability, — great necessity for oxygen, — -die soon,— 
almost immediately when taken out of the water, and have 
