Cream of Mushrooms

Wash and peel one quart of fresh mushrooms, put them into a quart of boiling
water, and boil until tender enough to rub through a sieve ; stir them in two quarts of
cream soup, as follows : take two tablespoonfuls each of butter and flour, and mix
until they bubble, then stir in one quart of hot milk and boiling water, a teacupful at
a time. When all the water and milk have been used season with salt and pepper.