HILL“ — FISH-POISONS. 
231 
existence among them. It is absent in many genera, and 
it is then substituted by a peculiar economy of efferent 
tubes. The compensatory energy of the liver in this class 
of organic beings must render it vastly congestive. We 
know that fish-liver contains an enormous quantity of oil— 
that fish-oil is an important article of commerce, and fish- 
liver oil is a valuable medicine ; but we knew besides, that 
these oils in a corrupt state are active poisons. Hence we 
may infer that the liver is a great operator in the injury 
done by deleterious fishes ; and if we but knew all the 
genera in which the gall-bladder is wanting, we might 
arrive at some rule for estimating the possible development 
of those prejudicial fluids that mingle from the liver with 
fish-flesh in cooking. 
Before adverting to the circumstances under which tunny 
fish, when becoming unwholesome, is condemned by the 
police in the market of Venice, it is necessary to remark 
some peculiarities in the organisation of the mackerel tribe, 
the family of fishes to which the tunny belongs. We have 
©numerated some instances of scomberoid fishes that are 
pernicious. We have mentioned the bonito, and nam- 
ing some of the caranxes and jacks, we have included the 
eoryphsena dolphin, the king-fish, and the Spanish mac- 
kerel among them. 
Everyone has remarked the lateral line that extends 
along the scaling of fishes from the gills to the tail, either 
interrupting or dividing the dermal imbrication. This 
line has a relation with the mucus that lubricates the skin, 
— “quelque appareil secretoire qui ©n suit la longueur.’* 
This lateral line is especially destinct in the tunny fish* 
Along it there occurs a peculiar reddening of the flesh. 
