Venetian Sauce

Have ready in a steamer or bain-marie saucepan one pint of veloute sauce (No. 415), and just when about serving add to it one gill of chicken (No. 398) or fish glaze (No. 399), some salt, pepper, and nutmeg, and a teaspoonful of good vinegar; thicken the sauce with egg-yolks and cream, then add two ounces of fresh butter, and a coffeespoonful of fresh parsley, also a pinch of finely shredded tarragon leaves.