Select very fresh milts, and suppress all the sanguineous parts; soak them for one hour, then lay them in a saucepan with some water, salt, vinegar, and parsley. Boil up the liquid, and remove it to the side of the range, and keep it thus for twelve to fifteen minutes in order to have them poached. They are to be served either with a Colbert sauce (No 451), or else milt a la Villeroi (No. 698).
Ranhofer's laitances are soft roe — the milt sacs of male fish, most often shad or herring in an American kitchen of the 1890s. The whole method turns on one thing: the liquid must never boil once the milts are in it.
Charles Ranhofer wrote The Epicurean (1894) out of thirty-odd years at Delmonico's in New York, and the garnishing chapter is essentially a parts catalogue — several hundred numbered components that cross-reference into the main dishes. Soft roe earned a place in it because nineteenth-century French kitchens treated laitance as a delicacy in its own right: rich, faintly sweet, and firm enough after poaching to be crumbed and fried, wrapped in pastry, or laid over a fillet as a garnish. Shad, running up the Hudson and Delaware every spring, gave American cooks a cheap and abundant source, and shad roe and milt were a seasonal fixture on New York menus for many decades. Milt has largely dropped out of Western cooking since, though it remains standard in Japan as shirako and in parts of Eastern Europe, where it is fried or served in soups.