From 1922:
Cut up one pound of gravy beef and simmer it for three hours in half a pint of water, with a little celery, carrot, thyme or other herbs. When it has simmered sufficiently, add three sheets of leaf gelatine, pepper and salt. Strain through a hair sieve. Take fillets of cold fish, arrange in a mould, or in little individual cups, pour over the broth, and stand in a cold place until set. A few cooked, green peas, chopped carrots, or lettuce can be placed first in the mould or cup, adding a little jelly before putting in the fish. Turn out when cold, and serve surrounded with lettuce.