As the air-bladders of cod are thick and of a gelatinous nature, the Icelanders frequently make _isinglass_ of them, similar to that which we usually import from Russia. By the Newfoundland fishermen the air-bladders are generally salted and packed in barrels under the name of _sounds_; and these, when good, are considered a great delicacy for the table. The _tongues_ are prepared in the same manner and for the same purpose. From the _livers_, after they have become in a certain degree putrid, a kind of oil is obtained which is considered superior to whale oil (118), because it preserves leather longer flexible, and, when clarified, yields less vapour in burning than that. The _roes_ are collected by the Icelanders, salted, packed in barrels, and sold to the Dutch, French, and Spaniards, as bait for anchovies and other fish. Before the commencement of the French revolution from 20,000 to 30,000 barrels of these roes were annually exported from Bergen. The inhabitants of some parts of Norway, when forage is scarce, dry the _heads_ of cod, and, mixing them with some species of sea-weeds, give them as food to their cattle. The London markets are abundantly supplied with fresh cod from the fishing banks adjacent to our own country. These fish are in season from the beginning of December till about the end of April; and are brought alive to the Thames in well-boats, the air-bladders being previously perforated with a pointed instrument, to prevent the fish from rising in the water. Cod should be chosen for the table of middling size, plump about the shoulder and near the tail, the hollow behind the head deep, and with a regular undulated appearance on the sides, as if they were ribbed. The gills should be very red, the eyes fresh, and the flesh white and firm. It is generally considered that the shoals of cod confine themselves between the latitudes 66° and 50° north. Those which are caught to the north or south of these degrees are both few in quantity and bad in quality. 206. _The HADDOCK_ (Gadus aglefinus) _is a fish of the cod tribe, which has three fins tip on its back, a small fleshy beard on the under jaw, the upper jaw the longer, and the tail somewhat forked. There is a dark oval spot on each side of the body a little below the gills._ _These fish seldom exceed the weight of seven or eight pounds._ Our markets are principally supplied with haddocks from the coast of Yorkshire and other eastern parts of England. They are best in season betwixt the months of July and January, after which they deposit their eggs or roe, and, for many weeks, are scarcely eatable; but those which have not begun to breed may be admitted to the table after this period. Their flesh, which in a degree resembles that of the common cod, is white, firm, well-tasted, and easy of digestion. Those that are best for the table do not usually exceed the weight of two or three pounds.