HILL — FISH-POISONS. 
23a 
their movements. The presence or the absence of the 
swimming-bladder has however no accordance with con- 
formation, or no relation with it. A species nearly ap- 
proaching the common mackarel, the Scomber pneumato- 
phorus, is provided with this organ, and bears a name from 
having it, as a distinction ; the Tliynnus vulgaris, is with- 
out it, while the Thynnus brachiopterus has it, though small. 
It is wanting in the Pelamys sarda, one of the bonitos, and 
in the Auxis vulgar is, another ; and occurs in the remoter 
scomberoid, the Tricliiurus lepturus , the cutlass-fish. It 
does not exist in the Corypheena dolphin, but is largely 
found in the caranxes or jacks. It is difficult to trace the 
effects of this difference in fishes of the mackerel family. 
Though the air-bladder 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. & Yal. Hist. 
Nat. 
We now turn to Cuvier’s account of the wholesomeness 
or unwholesomeness of the flesh of the Tunny-fish, to which 
our King-fish is nearly allied ; while the bonito is of the 
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 ap- 
proaches putridity. If the bones and the edges of the fish 
* Cuvier cites the experiments of Humboldt and Provencal for this 
fact ; he says : “ On a pense que la vessie natatoire pouvait etre aussi 
un auxiliare des organes de la respiration, et il est certain que lorsqu'on 
en price un poisson la production de Vacide carbonique par ses branchies est 
presque reduite a rien .” — (Hist. Naturel. des Poissons, Art Nutrition* 
pp. 522-528. 
