OX POISONOUS FISHES AND FISH-POISONS, 303 



may be no auxiliary in respiration, it must yet influence the circulation in 

 some respect, for " it has been ascertained that when a fish that has it, has 

 been deprived of it, the evolution of carbonic acid gas by the gills is 

 nearly reduced to nothing." * (C. & V., Hist. Nat. des Pois., vol. i., liv. ii.) 



We now turn to Cuvier's account of the wholesomeness or unwhole- 

 someness of the flesh of the tunny fish, to which our king-fish is nearly 

 allied, while the bonito is of tbe genus Thynnus or Tunny. 



" It is befitting that we remark," Cuvier says, " how the tunny is as 

 wholesome and agreeable when it is used fresh or salted, as it becomes 

 hurtful when it at all approaches putridity. If the bones and the edges 

 of the fish are reddened, the flesh immediately near this redness takes on a 

 sharp and acrid taste, as if it had been peppered ; and it. causes inflamma- 

 tion 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 in the sea. The freshest 

 tunny ought to be sold within twenty-four hours." (C. & V., Hist. Nat. 

 des Poissons, vol. viii., liv. ix., ch. ii.) 



What occurs with the tunny when decomposition commences on the 

 dead fish, is in reality the representation of the state of the living tissues 

 when the cognate fishes assume 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 respect 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 inversely 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 muscular irritability, great necessity for 

 oxygen, die soon — almost immediately when taken out of the water, and 

 have flesh prone to rapid decomposition. Mackerel, salmon, trout, and 

 herrings are examples. On the contrary, those fish that live near the 

 bottom of the water (' or feed on the ground ') have a low standard of 

 respiration, a high degree of muscular irritability, and less necessity for 

 oxygen, — they sustain life long after they are taken out of water, and 

 their flesh remains good for several days. Carp, tench, eels, the different 



* Cuvier cites the experiments of Humboldt and Provencal for this fact : he 

 says, " On a pense que la vessie natatoire pouvait Stre aussi un auxiliare des organes 

 de la respiration, et il est certain que lorsqv'on en prive un poisson, la production de 

 Vaxide ca/rbonique par ses branchies est presque reduite d Hen." (V. pp. 522, 526, 

 528— Nutrition.) 



