The recipe yield is:
From the Grand Dictionnaire de Cuisine, 1873: via Elizabeth David's ITALIAN FOOD. "Into a saucepan put 4 dozen *vongole* or small clams (cockles or mussels can be used as well). Pour over them three-quarters of a bottle of white wine and let them cook until they have opened. Drain them, setting aside the liquid in which they have cooked, and remove the empty half-shells. -- Chop the white part of a leek with a small onion, add a clove of garlic, and saute this mixture in a saucepan with good oil, add the liquid from the clams, and a quart of fish stock; add a peeled and chopped tomato, a bouquet of marjoram, and a few green leaves of celery. Let this bubble fast for ten minutes, remove the bouquet and the garlic, stir the clams into the soup, and pour it into the tureen. Serve separately small croutons of bread fried in oil."