This section is from the book "Cookery Reformed: Or The Lady's Assistant", by P. Davey and B. Law.
The freshness of fish is generally known by the gills and the eyes. When the gills are of a lively red and have a good smell, you may conclude they are new, especially if the eyes are full and not funk in the head, nor faded; for then they are stale. Another sign is the stiffness of the fish, particularly with regard to mackrel and herring; for if their tails are limber, their eyes faded, funk and wrinkled, they are stale.
A cod should be always thick towards the head, and the flesh white when cut. It is not necessary a large scate should be fresh caught, for it eats better when kept some days. Those turbuts are best that are thick and plump, with a cream-coloured belly. For if it be thin and the belly of a bluish white, it will not eat firm. Soals likewise should be stiff and thick, with their bellies of a cream colour, lour. Flounders and plaice should be stiff, with full eyes: but if they are limber and their eyes are dull and funk, they are bad. The flesh of sturgeon should be of a clear white and not crumble when cut; where any veins and gristles appear they should be blue.
The scales of pickled-Salmon should be stiff and shining; the flesh feel oily and part in flakes, without crumbling or appearing spongy. Pickled herring when opened on the back to the bone should have their flesh white,sleek:,and oily. Red-herrings should be glossy, part readily from the bone and smell well. Dried-ling is best when thick at the poll and the flesh yellow.
Boiled-lobsters should be heavy, without water in the body, with a stiff tail which shuts as if it had a spring. A cock-lobster has a narrow tail; that of a hen-lobster is broad. Prawns, crawfish and shrimps, may be chosen in the same manner as lobsters.
When the fish are to be fry'd, they must, be dry'd very well with a clean cloth, and afterwards flour'd. Then put beef dripping, or hogs-lard into a very clean stew-pan, and let it boil before you put in the fish. Then fry them quick till they are of a fine light brown, but not deeper. Turn them with a fish slice; and when they are enough, take them up, and put them in a dish with a coarse cloth over it "to soak up the fat. When you fry parsley it must be done quick, and taken out of the dish as soon as it is crisp, otherwise the colour will be spoiled. Roach, dace, smelts, and the like, should be fry'd as dry as possible. Then put plain butter in a cup and garnish with lemon.
All the sauce that is required for boiled salmon, is likewise plain butter; garnish with horse-radish and lemon. When you boil any sort of fish, except mackrel, you must put a good deal of salt and horse-radish into the water. When mackrel is to be boiled, put mint, parsley, fennel, and salt into the water, which must be afterwards chopt to mix with the butter. In general, fish must be well boiled, but great care must be taken that they don't break.
When you bake fish, butter the pan and lay a very little water in the dish. Throw salt and flour over them, and lay them in the pan. Then stick bits of butter, or dripping upon them, and put in an onion and a bundle of sweet herbs. Let them be baked of a fine light brown, and when they arc enough, lay them on a dish before the fire. Skim off all the fat from the liquor in the pan, and then strain the latter, which must be mixt either with the fish sauce, or strong soup or catchup.
 
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