Wash and pare each shoot of asparagus, cutting off the tough end, or butt. When you have finished, throw the asparagus into cold water for thirty minutes. Tie in small bundles and put them straight into a kettle of boiling salted water allowing a teaspoonful of salt to each quart of water. Boil for thirty minutes. While the asparagus is boiling, toast four slices of bread, trimming the crusts. Rub together two tablespoonfuls of butter and two tablespoonfuls of flour; add a half pint of the water in which the asparagus was boiled; stir until the sauce boils; add a quarter of a teaspoonful of salt and a half saltspoonful of pepper; add the juice of half a lemon and strain the sauce into a heated sauceboat. Lift and drain the asparagus and arrange it crosswise on the toast on a platter, having the heads all one way. Send at once to the table. Asparagus may be boiled and served with sauce Hollandaise or English drawn butter.